Is Air Conditioning Contributing to Coronavirus Spread?

Reposted from The Cliff Mass Weather Blog

Monday, July 13, 2020

The headlines are screaming about recent increases in coronavirus cases, with some suggesting that the essential problem is the loosening of the lockdowns and restrictions.  A number of media sources note that many of the problematic locations are “red” states with Republican leadership. 

It is not surprising that moving out of lockdown resulted in more COVID-19 cases.  In addition, the increasing number of tests undoubtedly increases the number of known infected.

But could there be something else going on?

Could increased use of air conditioning, particularly in the southern tier of states, be a significant driver of increasing number of COVID-19 cases?

This blog will attempt to help answer this question.

So where is the virus really spreading?   A good way to see the problem locations is to view the percentage of positive tests.  A worsening epidemic is signaled by a higher percentage of positives, assuming there is widespread testing.  Positive percentage is far better than number of positive tests, which, of course, varies by the amount of testing.

Here is a plot of the positive percentage on July 7th.  The big problem states were Arizona, followed Mississippi, Florida, South Carolina, Texas, Georgia, Alabama, Nevada, and finally Idaho.

Below is a different type of plot that shows the same thing, but provides the actual numerical values.  The bottom line:  the situation is far worse for states along the southern tier of the U.S.  Arizona is the worst, with Mississippi and Florida right behind.  These are states with very different demographics.

But what do these states have in common?  Some media outlets are pushing the fact that most of these states are dominated by the Republican party and have been quicker to open up.  But they have something else in common:  these states have had high temperatures with a lot of air conditioning use.  (And no, there is no reason to think that heat turns people into Republicans).
If we look at the high temperatures in June (shown below, NOAA division dataset), southern Arizona (including Tucson) is the nation’s hot spot–and yes, it is the hot spot for COVID-19 as well.    Mississippi, South Caroline, Florida, Texas are all very hot.  And according to U.S. Census data nearly all homes and most restaurants in these states have AC.

And an independent graphic, showing the high temperatures averaged over the 30 days ending July 7th (Climate Prediction Center), has a similar pattern.  Arizona has the highest temperatures.

So let us consider a hypothesis: the rapid warming in late spring led to greatly increased use of air conditioning in homes, stores and restaurants in the warm, southern tier states.   More people are thrust into interior spaces with recycled, recirculating air that increases COVID-19 spread, something described in several research papers.  And the cooler, drier conditions associated with air conditioned spaces are favorable for COVID-19, and the blowing air spreading COVID-19 containing droplets and aerosols.
Now is this hypothesis consistent with observations?     We can begin by looking at the total tests and percent of positive tests in Arizona (see below).   Tests went up substantially in May and June, but so did the percentage of positive tests, which has progressively risen since mid-May (the largest increase was in mid-June)

So what happened in Tucson, located in southern Arizona during June?    Temperatures exceeded 100F on many days and over half of the month was above normal (green shows the normal range).   Some days were way above normal.  June is the worst month in southern Arizona–very, very hot without the relief of the southwest monsoon in July.  Air conditioning was a necessity and this miserable period is exactly when the virus surged.

Florida had a similar story.  Positive percentages surged in middle and late June.

And this is exactly when temperatures surged to way  above normal in southern Florida (see below). And Florida has terrible humidity as well.  Folks were forced to flock to air conditioned spaces.

You want something more rigorous?  No problem.

If I was writing a paper on this topic, I would present a scatter diagram plotting the temperatures against positive percentages of COVID-10.  And I have done exactly that below.  Specifically, I found the June average maximum temperature for every state in the continental U.S. and its corresponding positive percentage for COVID-19 (Y-axis percentage, X-axis is average high temperature).  Each state is shown by a blue dot.  I only plotted states with max temperatures in June of 75F or more, which excluded a handful of states that are very cool and have very few air conditioners (e.g., WA, OR, and Montana).

I also plotted a best-fit line (red).   There DOES appear to be a relationship between COVID-19 infection rates and temperature.  The correlation coefficient is .69, which suggests this relationship explains about 48% of the variability.   That is quite a bit.  The point in the upper right corner?–Arizona.

Now certainly there are a number of factors that help explain the variability of COVID-19 infection rates around the U.S.     But I do think the above results are very, very suggestive that very warm temperatures result in increasing infection rate.  Not because the virus likes warm temperatures (it does not, as shown by a number of studies), but because warm temperatures push people indoors into air conditioned spaces in which spread is greatly enhanced.  Restaurants and bars are probably key here.

In warmer climates, summer is the time when folks huddle together in confined spaces and thus the greatest potential for COVID spread.  The implication of all this is that the situation might be expected to worsen over the southern tier states and into the warm/humid areas of the southeast over the next month or so, but improve during the fall.  Clearly, there is reason to avoid air conditioned interior spaces during a COVID epidemic, and dining should mainly limited to outdoor spaces, which should be quite safe.

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Ian W
July 14, 2020 2:43 am

It is not so much that people huddle together, the design of air conditioning is that cold air is blown into the room usually from the ceiling or wall vents across the people in the room. The result (as was shown in a Chinese paper) is that anyone downstream of an infected person, say for the duration of a meal, regardless of social distancing is being bathed in droplets and viral particles being blown across the room. Many air conditioning filters are cheap and coarse and will not trap viral particles so the recirculated air is pumped to all spaces in the building served by the air conditioner.

If you were to design a system to spread a viral respiratory disease you would create a system to blow dehumidified cool air across a group of otherwise socially distanced people; precisely the design of the easy to build air conditioners.

A better system would be to pump the cool air at the desired room temperature into the room at floor level and extract warmer air at ceiling level. The extracted air to be passed through a heat exchanger to cool and extract the heat, then HEPA filters perhaps even UV lights to disinfect the air, before being returned at floor level to the room.

Reply to  Ian W
July 14, 2020 4:02 am

New construction results in well sealed buildings that require ventilation. That, in turn, requires a heat exchanger. You bring in fresh air and exhaust stale air and you don’t lose a lot of heat in the process.

Your comment about air flowing past infected people and toward others makes me think about fume hood design. The trick is to arrange the airflow so that fumes aren’t sucked past people’s faces. Similarly, from now on, restaurant and bar air flow has to be vertical. Patrons shouldn’t be exposed to the pathogens of other people.

Just as air conditioning used to be a selling point for theaters, etc., proper airflow could become a selling point for restaurants and bars. The down side is that the work required is horrendously expensive.

Reply to  Ian W
July 14, 2020 7:00 am

A/C is precisely the reason I have my windows open and am not using the A/C in my house. It needed recharging this year, but I decided to let it go. Fresh air is better for you.
Yes, I know: the CV19 virus can fly right in through the living room windows. Well, so can flies and bees if I don’t have screens on the windows. But then, the people in my neighborhood are staying indoors and not blowing viruses around, so that’s a moot point.

Reply to  Ian W
July 14, 2020 11:09 am

cut the crap…..”Florida had a similar story. Positive percentages surged in middle and late June.”

Florida doubled and tripled the amount of tests they were doing…look something up with it’s that obvious

Reply to  Latitude
July 14, 2020 1:04 pm

Okay, say it with me, nice and slow — P E R C E N T A G E S. Percentages don’t care how many tests you do, they measure the RATE, not the quantity!

Rhoda R
Reply to  Steve
July 14, 2020 3:42 pm

Steve – there are labs in Florida reporting 100% positive test results from all this increased corona testing. There are enough labs that the Florida MEDIA is pointing this out. Take Florida’s test results with a huge salt-like sized grain of salt.

Reply to  Rhoda R
July 14, 2020 7:54 pm

Just read these reports. Also have 3rd party reports of people sighing up for testing, doing the paper work, but leaving before the test (time issues). Get positive results in the mail.

Reply to  Steve
July 14, 2020 10:45 pm

As far as I know, the people getting testing are those who come to the attention of the medical industry. Either they have CV symptoms, or they are admitted to a hospital for another reason. I’m not aware of any place in the US that is testing a random sample of the population with the PCR test. The population of people being tested is very biased.

Given that, please explain the significance of the percentage of positive tests.

Reply to  pls
July 15, 2020 5:48 am

on the test topic;
Health authorities in Australia and across the world have been using the test and trace method in the battle against the deadly disease, but there are fears a disturbing number of cases are being missed.

Research from Johns Hopkins University in the US found people with the virus rarely returned a positive result during the first three days of their infection.

Instead, researchers found testing was more accurate between day six and eight of being infected, but even then it’s missed in one in five cases.

and would aircon be an issue
think cruise ships, then think about Legionella
hmm gee
how many stores homes clubs or pubs clean their filters weekly let alone more than once a day?
1 victorian went to nsw
an office and then they went to a pub to celebrate
theres 30+cases from the direct pub link within 3 ?days and rising daily with community spread.
quite likely they were using the reverse cycle aircon/heating system so it got well shared very fast

Steven F
Reply to  Latitude
July 14, 2020 5:14 pm

Most people going to hospitals are not their because they had a positive test result. Most People go to the hospital because they are so sick they think they are going to die. When they get their they get emergency car and doctors test for Covid 19. Today most of the time the test comes back for positive for Covid 19.

Farmer Ch E retired
Reply to  Steven F
July 16, 2020 2:45 pm

Did anybody notice that the US daily deaths began to increase 18 days after the FDA revoked the HCQ Emergency Use Authorization? The data is unmistakable when plotted as a 7-day moving average. The FDA action was June 15 and the declining deaths began to steadily increase on July 3. Hummm . . .

George T
Reply to  Ian W
July 14, 2020 1:53 pm

Drawing the air downward (Down draft hood concept) toward the floor (away from the breathing zone) would be a better than general dilution which is what is seen in restaurants, bars etc…

July 14, 2020 2:44 am

Bingo! Not opening up, not rioting, but the human refusal to acclimate to ambient temps when AC is available. Open the windows, buy a few big fans, resolve yourself to a little discomfort, and avoid Wuflu. At the very least, turn off the AC after sundown and open up one’s home to the wafting zephyrs of virus-free air.

Reply to  Pameldragon
July 14, 2020 3:32 am

Covid19 is spreading relentlessly in Brazil and India, a/c not making much difference there.

Patrick MJD
Reply to  Loydo
July 14, 2020 3:37 am

Not many deaths in India though. Why is that? Heck, more people commit suicide on the rail lines than have died from COVID-19.

Reply to  Patrick MJD
July 14, 2020 4:06 am

“Not many deaths in India though.”

I don’t think you’ll be saying that in a couple of years.

Ian W
Reply to  Loydo
July 14, 2020 4:57 am

India – 101,261 cases, 3,164 deaths 2.0 deaths per million
USA – 1,550,294 cases, 91,981 deaths 278.0 deaths per million

India uses HCQ early and prophylactically

Patrick MJD
Reply to  Loydo
July 14, 2020 4:58 am

“Loydo July 14, 2020 at 4:06 am

I don’t think you’ll be saying that in a couple of years.”

A prediction that won’t stand the test of time.

Tom in Florida
Reply to  Loydo
July 14, 2020 5:51 am

Your stats for the U.S. are wrong. So why should I believe your stats for India?

Reply to  Loydo
July 14, 2020 7:17 am

Hi, Loydo. On the wrong end of every argument, again.

Joel Snider
Reply to  Loydo
July 14, 2020 7:52 am

He’s really hoping for disaster.

Reply to  Joel Snider
July 14, 2020 3:34 pm

Leftards love death, as long as it is not THEIR death. Mao, Lenin, Stalin, Adolf, Tito,Castro, Pol Pot, Chavez, they all loved death as long as they were the ones handing it out.

Reply to  Patrick MJD
July 14, 2020 4:15 am

@Patrick MJD
Ever heard of underreporting?

Most numbers from developing countries about the virus are not reliable at all. No resources to do an accurate job. Damn, look just at France how bad reporting was for a long time and you get an idea.

Patrick MJD
Reply to  Ron
July 14, 2020 4:56 am

Ever heard of countries prone to malaria (Africa/India etc) and treated for such are not experiencing the same COVID-19 outbreaks? Of course, they are underreporting.

Robert W. Turner
Reply to  Ron
July 14, 2020 7:10 am

Covid deaths in a place like Africa are a mere blip when you consider the diseases they deal with – tuberculosis and malaria.

Reply to  Ron
July 14, 2020 11:05 am

Africa is really not known for an epidemic representation of the fatal co-morbidities in COVID-19: hypertension, diabetes, obesity

Might explain it better than any malaria drugs people cannot afford anyway. The malaria drug number one there is called mosquito net.

Krudd Gillard of the Commondebt of Australia
Reply to  Ron
July 14, 2020 5:15 pm

C’mon man, our governments give $$$billions each year to UN bodies for do their work in Africa etc. They would be all over it if there were significant numbers of deaths from COVID-19.

Fact is, it would seem COVID-19 is a problem only in developed countries.

Reply to  Patrick MJD
July 15, 2020 5:51 am

they use HQ for malaria..and possibly the artemisin as well?
may also have Ivermectin use
and NEEM hmm its very very widely used for multiple purposes I wonder if anyones looked at itfor virus control?

Reply to  Pameldragon
July 14, 2020 8:05 am

Where do you live?

Reply to  MarkW
July 14, 2020 9:57 am

I live in Vila do Conde, northern Portugal. Yesterday it was 32C but today is 26C with a very brisk onshore breeze. We don’t even have AC except in the car. I realize my experiences are not typical, but none of my friends or neighbors have sickened or died. I have friends in their 80s as well as younger. We aren’t missing anyone.

Oh, just an aside on testing. I was tested last week because of a nasty attack of food poisoning, also didn’t kill me. Test was negative with results within an hour. My husband was tested in Doha, two types of test, Q-tip jammed up the nose and another down his throat. His results are still a mystery. A young friend in eastern Pennsylvania was tested two weeks ago and STILL has not gotten her results. She was told to stay home until such time. She is the sole support of her small family of four.

It doesn’t matter if you test negative, that result is only valid for the time up to the time of the test. You can easily walk out of the hospital and straight into the arms of WuFlu-Mary. Tests are essentially worthless but they apparently provide a bit of relief from fear for some.

IMO, it is the death count, they actual, verified, not padded or hyped to get more money from Medicare, death count. Eventually all the dirty little secrets will slither out, the truth tends to do this, and we can only hope the Global Economy can be rescued.

Reply to  Pameldragon
July 14, 2020 11:00 am

Around here the highs have been ranging from 34C to 37C for the last 2 weeks and will stay that way for most of the next month. Humidity has been been ranging from around 65% to 75%.
Most of the time there is little to no breeze. As you go south from here, both temperature and humidity go up.

Mark A Luhman
Reply to  MarkW
July 14, 2020 2:22 pm

I in Arizona it presently 41 C later today it will be around 43 C it looks to remain that way the rest of the week. 43 C in the wind you feel the heat in your eyes at first, takes them a while to adjust. Of course on the pavement my in vehicle thermometer registers above 47 C late afternoon. I expect I will mow a small patch of grass this in those temps this evening. We quit eating outside about three weeks ago when it started to be over 39 C . Phoenix hit 46.6 C on Friday. My air condition went out in my vehicle in June we drove to Phoenix and back in 43 C temps. One would hope not to do that again anytime soon. We are somewhat dry dew points are in the 11 C range, that twice of what June was. 26 C is where my AC is set at at my house.

Steven F
Reply to  Pameldragon
July 14, 2020 5:35 pm

You really don’t know what hot is until you experience it. In Pheonix Arizona the average summer temperature is always above 37C for every day for 3 to 4 months of the year. And often it is over 40C. And occasionally the nigh time low is 37C. Furthermore during the summer there is often no wind and ocean to moderate the heat. So in pheonix you don’t get a break from the heat at night.

In texas the temperature is a little lower but the humidity is vastly higher. Same for the states east of texas.

Reply to  Steven F
July 14, 2020 10:40 pm

You can tell the original post author doesn’t live in Arizona or he wouldn’t be referring to the monsoon as “a relief”. I don’t mind 38 to 40 C in June when it’s dry. 40 C during the monsoon is pretty bad.

I’ve seen plenty of report of bad CV data recently. NY, NJ and a few other states rolled antibody tests in with the viral PCR tests and reported all the antibody tests as new cases in the same week. It’s reported that AZ has taken presumed CV cases from Feb, Mar, and Apr and is reported them as new cases starting in mid June. Part of the problem is reporting with the date added rather than date of diagnosis.

I don’t know how many CV cases we really have. It is my firm belief that the data is so bad that nobody else knows either.

Reply to  MarkW
July 14, 2020 11:01 am

I might add, that when it does get down to 26C most of the people around here don’t use the AC either.

The Dark Lord
July 14, 2020 2:46 am

safe ? that assumes catching covid is unsafe … which is a myth for 95% of the population …

Reply to  The Dark Lord
July 14, 2020 3:05 am

So infecting just 16 million with a nasty, often fatal, disease is OK with you?

Patrick MJD
Reply to  steveta_uk
July 14, 2020 3:36 am

“steveta_uk July 14, 2020 at 3:05 am

So infecting just 16 million with a nasty, often fatal, disease is OK with you?”

192 deaths in Australia when predictions of 150,000+ were what was used to bring the country to it’s knees. 90% over the age of 65 with comorbidity issues. That’s about as safe as crossing the road or risking a dodgy takeaway.

Aidan Donnelly
Reply to  Patrick MJD
July 14, 2020 4:22 am

“192 deaths in Australia ” – actually 104 – all elderly with serious pre-existing conditions.
West Oz has not even had one positive test in over 2 months.

Patrick MJD
Reply to  Aidan Donnelly
July 14, 2020 4:59 am

Last figure I saw was 192. I guess we can’t trust the media. Either way, no justification for the panic.

Robert W. Turner
Reply to  Aidan Donnelly
July 14, 2020 7:30 am

Can’t trust the media? You don’t say? Have you seen the latest fake news circulating the propaganda networks about the covid parties and nameless 30 somethings confessing on their death?

Reply to  steveta_uk
July 14, 2020 4:00 am

What a laugh. Being on a ventilator is often fatal.

Reply to  steveta_uk
July 14, 2020 6:07 am

The latest from WorldOMeters (July 14, 2020 12:56 GMT):

4,954,838 Currently Infected Patients
4,895,576 (99%) in Mild Condition
59,262 ( 1%) Serious or Critical

I regret the almost 60,000 in serious or critical condition, but I like those odds.

Robert W. Turner
Reply to  PaulH
July 14, 2020 7:08 am

Doesn’t even count the 50% with no symptoms at all and likely aren’t tested. Random antibody testing is confirming that the virus is far more widespread than previously presumed.

Death counts in the US are also counting as Covid death in patients with pneumonia or influenza and influenza deaths since February are at least half if not more under what should be expected. They are also putting the Covid code on death certificates when no test was actually done to confirm it, they are presumed Covid deaths.

A quick look at excess deaths and comparing to deaths with only covid suggests that the actual number of deaths so far from Covid in the US is actually between 55,000-65,000. Half of which were likely caused by just a few Democrat governors forcing SARS-2 into their nursing homes.

Greatgranny Jan
Reply to  Robert W. Turner
July 14, 2020 8:14 am

In Washington state, the state had to remove 3 homicides and 2 suicides from the COVID death count

Reply to  Robert W. Turner
July 14, 2020 3:58 pm

Why Everyone was wrong

The author, Beda M Stadler is the former director of the Institute for Immunology at the University of Bern, a biologist and professor emeritus:

Firstly, it was wrong to claim that this virus was novel.

Secondly, It was even more wrong to claim that the population would not already have some immunity against this virus.

Thirdly, it was the crowning of stupidity to claim that someone could have Covid-19 without any symptoms at all or even to pass the disease along without showing any symptoms whatsoever.

Reply to  Robert W. Turner
July 14, 2020 10:42 pm

Don’t forget that George Floyd in Minneapolis was counted as a coronavirus death.

Mark A Luhman
Reply to  steveta_uk
July 14, 2020 2:32 pm

Steve, ho do you prevent that enlighten me! Shutdowns don’t work only slow it down, does not stop it. As with all virus this on will follow Farr’s law how long it take to get to have an R below one is all dependent on how long it takes to infect enough people so the R can drop below one. Nothing we can do at this time will change that, we do this give HCQ prophylactically to everyone or a large enough of the population. That leaves a vaccine and like most viruses this one may very well die out before we get clinical trials done. I also will not believe we have save lives, other than those that did not die on the highway due to auto accidents, we certainly cause increased mortality in cancer, heart disease and drug overdose.

Reply to  Mark A Luhman
July 14, 2020 6:42 pm

Nope. didnt follow Farrs law in Korea or HK or Singapore or many us states
that why it not a LAW.

Its a non mechanistic data fit that sometimes works and sometime fails

If you Aggregate data spatially then it will kinda work, But for LOCAL areas and your personal


Reply to  The Dark Lord
July 14, 2020 3:26 am

Does Covid have a 5% mortality rate?

Are deaths declining or rising?

Robert W. Turner
Reply to  Derg
July 14, 2020 6:12 am

Less than 1% overall but close to 0% for healthy people under the age of 65.

Reply to  The Dark Lord
July 14, 2020 8:07 am

There is growing evidence the ChiCom-19 leaves long lasting coronary and psychological impacts on people with even mild cases.

Bob boder
Reply to  MarkW
July 14, 2020 8:42 am

Mark W

Have not yet seen that, can you site a few sources?

Reply to  MarkW
July 14, 2020 10:15 am

They need to factor in damage done by ventilation. Sedatives used for ventilation damage the nervous system, and rhythmic air pressure not only damages lung tissue via barotrauma, but also damages distal organs (e.g., heart, kidneys, liver) via biotrauma, i.e. endothelial release of cytokines via mechanotransduction that cause systemic inflammation.

Our data implicate that MV [mechanical ventilation] causes endothelial activation and inflammation in mice without pre-existing pulmonary injury, both in the lung and distal organs.

Reply to  MarkW
July 14, 2020 11:04 am

Why do you assume that any, much less all of the people being referenced were ventilated?

Can I assume that your evidence that ventilators kill people is on the same order, as your evidence that vaccinations on’t work?

Reply to  MarkW
July 14, 2020 12:03 pm

I didn’t assume all were ventilated. What makes you think none were? Since it was the standard primary treatment, and still is in numerous places, it’s logical to assume that some number of those with lingering health issues were intubated. I suspect that number is very high because all of ill effects described are documented, known side effects of intubation, and I have seen no evidence that they are caused by the virus.

Reply to  MarkW
July 14, 2020 1:25 pm

It’s not a standard treatment. It’s only for the worst cases.

Reply to  MarkW
July 14, 2020 2:37 pm

As usual you make a statement trying to sound like an authority when you really know little to nothing about the matter.

Reply to  MarkW
July 14, 2020 3:03 pm

Here’s an example that shows you have absolutely no idea what you’re talking about. You’re regurgitating a talking point you’ve read somewhere. The current obsolete paradigm would mandate that this patient with a sat of 64% be intubated immediately. Your worse case patient… who would likely be dead if intubated. But he wasn’t because he had a competent doctor, and he lived.

To our friends in Arizona and Texas. He walk in, sat of 64%. Was talking, alert. Place on
@Vapotherm At 40l/100% with a face mask, taught awake pronation…#covid+ PaO2/Fio2 85. Sent home today! 8 days in hospital. Please do not intubate too early!

Reply to  MarkW
July 14, 2020 5:33 pm

Mental status changes are par for the course in septic elderly patients, regardless of etiology, in fact, many times it is the predominant , or only sign which triggers family members to seek medical care. All the articles allude to the elderly being the group most affected .No age specific rates are sited, and these findings are known to occur in the elderly population infected with other agents , so these findings may be to some degree , the product of extensive investigating . I wonder whether the number of autopsies, particularly a thorough search for the extent and type of tissue damage ,has ,in 2020, been much more common than in past years. In past years , tens of thousands of Americans have died of, or with respiratory infections , without identification of the infecting agent

Reply to  Bob boder
July 14, 2020 9:24 am

What I’ve seen so far is hearsay and speculation that ignores the residual damage done by toxic treatments.

Reply to  icisil
July 14, 2020 11:02 am

Everything bad is caused by doctors. Gotcha

Reply to  icisil
July 14, 2020 12:04 pm

Everything bad is caused by the virus. Gotcha

Reply to  icisil
July 14, 2020 1:26 pm

It really is sad when paranoia causes the last few brain cells to stop working.
Your belief that all doctors are quacks and that the medical profession is only after your money is really a shame.

Reply to  icisil
July 14, 2020 1:35 pm

It shouldn’t be necessary to point this out, pointing out that Covid19 is not the minor bug that you are so desperate to believe it is, is not the same thing as saying everything bad is caused by it.

Reply to  icisil
July 14, 2020 2:40 pm

You really should be ashamed of yourself for mischaracterizing me that way, but you won’t because that’s just you.

Reply to  icisil
July 14, 2020 2:46 pm

The data show that covid is not a generally dangerous illness. Most people aren’t bothered by it. Most who get sick survive. Most of those who die are people at the end of their life in nursing homes, people who are already really sick and people who are put on ventilators as a matter of policy and ignorance rather than their physiology. Ventilation k!11s healthy people as well as sick ones. If you don’t understand that, you don’t understand anything.

steven F
Reply to  Bob boder
July 14, 2020 5:44 pm

recently the news reported one 20 year old and one 37 year old that needed and got a double lung transplant. And there are many that suffered brain damage from a Covid 19 caused stroke. And others are left with permanent damage to hearth kidneys and other organs.

Reply to  The Dark Lord
July 14, 2020 9:43 am

Russian Roulette is safe, too, for 5 out of 6 players.

Reply to  mcswell
July 14, 2020 9:58 am

Are you implying Covid has a 5/6 survival rate?

Reply to  Derg
July 14, 2020 7:48 pm

No, but I had to scroll a L O N G ways up to remember what I *was* replying to. It was this, by someone calling himself “the Dark Lord”: “that assumes catching covid is unsafe … which is a myth for 95% of the population”. I realize that 5/6 is different than 19/20, but I wouldn’t play Russian Roulette even if it were safe for 95% of the players. The point I was trying to make was that his comment was irrational.

Reply to  The Dark Lord
July 15, 2020 5:55 am

might be a bit optimistic
followups are showing even milder cases are showing heart damage and lung issues ongoing

its a gift that keeps on giving;-(

July 14, 2020 3:04 am

Viruses (including this coronavirus) survive the longest in cold and dry air. Guess what comes out of an AC.

This is, in my opinion, another reason (next to reasons above), that ACs are causing some corona infections.

Reply to  Peter
July 14, 2020 4:31 am

“Viruses (including this coronavirus) survive the longest in cold and dry air. Guess what comes out of an AC.”

Haha! Not here in Florida! All we get is cool, wet air 🙂

Reply to  NavarreAggie
July 14, 2020 9:47 am

That’s not AC; that’s a swamp cooler.

Reply to  jorgekafkazar
July 14, 2020 10:45 am

Oh, no, it’s definitely air conditioning utilizing a refrigeration cycle. 70% humidity feels dry when it’s nearly 100% ambient humidity all the time! LOL

Reply to  jorgekafkazar
July 14, 2020 12:06 pm

Swamp coolers don’t work in humid places like FL.

Reply to  icisil
July 14, 2020 8:02 pm

Those that think a swap cooler will work in Florida, should go live in a swamp for a week in South Florida.

Lee Alison
Reply to  jorgekafkazar
July 14, 2020 1:10 pm

Arizona heat = convection oven.
Florida heat with swamp cooler = steam cooker.

July 14, 2020 3:07 am

Restaurants should have a UV filter where all the air passes through before entering the room.

Reply to  Robertvd
July 14, 2020 3:33 am

+1 – blast the air with UVC.

Patrick MJD
Reply to  Eric Worrall
July 14, 2020 4:25 am

There is very little natural UV-C at ground level. More UV-B.

Bob boder
Reply to  Patrick MJD
July 14, 2020 8:25 am

the problem would be having enough time under the light. Also using copper filters would help as well. ultimately this is the answer though finding a way to make the AC units kill viruses would help with every illness. maybe back to electro static?

Reply to  Robertvd
July 14, 2020 4:24 am

My church is proud that they installed UVC in the HVAC ducts. Probably worthless. Not enough contacts time.
Study of UVC in HVAC indicates it’s only effective for killing biotics on the coils if located to shine directly on them, and has no effect on particles sailing past at 20 fps.
I recommended UVC in elevators 3 months ago.

Michael S. Kelly
Reply to  Enginer01
July 14, 2020 9:37 am

Hospitals use UVC in the HVAC ducting. They’re called germicidal lamps, and consist of a quartz mercury vapor plasma tube (or bulb) inside a filter that cuts off the UV above about 265 nm (to avoid producing ozone). Fairly recently, UVC diodes have been developed that peak at 265 nm, and are much more efficient than the mercury vapor lamps. I’m not sure of their availability, but mercury germicidals are available in a huge variety of shapes and sizes.

A favorite restaurant of ours in Georgetown, Filomena, recently reopened having implemented a number of prevention steps. One of them is to expose as much surface as possible to UVC after hours. It doesn’t seem like a difficult thing to me. In fact, I’ve used them myself.

Reply to  Michael S. Kelly
July 15, 2020 4:15 am

You are preaching to the choir, brother. Most people who read and comment here already know about this tech.

Reply to  Enginer01
July 14, 2020 3:38 pm

You are absolutely right! Don’t try at all, THAT will advance the Human Race.

Ian W
Reply to  Robertvd
July 14, 2020 5:15 am

The problem is after the air enters the room. It is cool low humidity air and blows the infected person’s plume of viral particles and breathed droplets and carries them to other diners in the draft from the air conditioning.
The design is cheap but almost purpose built to spread respiratory diseases.

Robert W. Turner
Reply to  Robertvd
July 14, 2020 7:12 am

Using a tanning bed will probably decrease your chances of contracting covid down to 0.1% but tanning salons will certainly be kept closed by all the Chicken Littles in charge.

Reply to  Robertvd
July 14, 2020 11:27 pm

There is a point there. Anti-smoking laws contribute to CV-19 spread.

Reason? When smoking was generally allowed, most bars and restaurants had smoke filters that circulated the air through either a HEPA filter or an electrostatic precipitator. Anything that will remove smoke-sized particles should also remove respiratory droplets just fine.

Now, with anti-smoking laws, you almost never see the air filtering machines.

Roger Knights
Reply to  pls
July 15, 2020 1:44 am

I read a comment recently that smokers are less at risk of catching Covid-19. (Hopefully this will apply to vapers too.)

Reply to  Roger Knights
July 15, 2020 5:59 am

yup quite a few documented studies
the anti smoker/anti everything were all over itlike a rash
duno re vaping if its the nicotine doing the protecting then yes
if its the other 4kchem i n real baccy smoke doing it?
no ones sure
the french were slapping nic patches on patients
havent heard what results if any

William G.
July 14, 2020 3:24 am

Good post! And in the winter most of the cases were in the northern states, everyone was locked in with low humidity and warm atmosphere.

Stephen W
July 14, 2020 3:28 am

I live in Queensland, Australia.
In southern states where daily maximums are around 15degrees celcius there has been a rise in cases recently. There are now thousands of active cases in the state of Victoria.

In my state, warm sunny Queensland, winter time means we can be outdoors, no aircon or heating required in bars, restaurants or homes. It really is a wonderful time of year.
Current active cases in my state.. four! With next to nil restrictions.

Anecdotally, every flu I have ever gotten I have gotten in the warmer months. October-Feb. This year in fact I got a particularly nasty flu in February. Fever, body aches, breathing difficulties, cough, runny nose.

Reply to  Stephen W
July 14, 2020 3:38 am

Is Covid a flu?

Reply to  Derg
July 14, 2020 7:19 am

No, a cold.

Reply to  Chaswarnertoo
July 14, 2020 3:22 pm

Which is a variation on flu.

Craig from Oz
Reply to  Stephen W
July 15, 2020 1:31 am

1931 active cases in Victoria. Calling that thousands is stretching it a bit.

Of more interesting is the claim from the chart WAAAAAY back in the original article that suggests that WHO recommend not re-opening an area unless the cases to test percentage is under 5.

Victoria at the moment is testing about 26,000 a day and finding about 200.

If my fingers and toes are correct that is less than 1%

Seems to me that Victoria needs to stop being a vassal of China and harden up.

Bob boder
Reply to  Stephen W
July 15, 2020 7:12 am

Maybe you had covid

Patrick MJD
July 14, 2020 3:40 am

Legionnaires disease how is that most commonly spread? Confined spaces with recirculating air?

Reply to  Patrick MJD
July 14, 2020 5:14 pm

When I saw this, I immediately thought about Legionnaires disease in Phila:

I thought that it would be mentioned in the article !


Chris Wright
July 14, 2020 3:56 am

There’s a well known saying: correlation does not prove causation.
I think that air conditioning could help the spread of the virus, but I would like to see stronger evidence that it has caused the apparent increase in the southern, hotter states. It could easily be a coincidence that cases have been increasing at a time when temperatures are naturally rising.

I’m pretty sure that the case numbers around the world are very misleading. Obviously, as testing increases there will be more positives. The tests themselves may have changed over time and become more accurate, resulting in more genuine positives.

Although far from perfect, I think the data for deaths is far more reliable, though it will lag cases by around four weeks. Look at the WHO global data:
Daily cases have been rising since mid-May and have roughly doubled. There should be a corresponding rise in deaths after several weeks. But there is no sign of that. Daily deaths have been remarkable flat since the beginning of May.
It’s the same story for the US: daily cases doubled since the end of May, but no increase in deaths. In many countries, including the UK, both cases and deaths have declined with no sign of a second wave.

Ironically, an apparent increase in cases due to more testing is good news. It confirms that most people who get infected don’t even get ill. For the others, the great majority suffer symptoms similar to common flu. It also means the death rate is much lower, almost certainly well below 1%.
President Trump has stated that cases are increasing because tests are increasing. Although there are almost certainly other factors such as reductions in lockdowns, I think he’s probably basically right.
Unfortunately, the combination of more cases due to more testing and media hysteria is a perfect storm leading to far more human and economic destruction.

Reply to  Chris Wright
July 14, 2020 4:27 am

If the number of cases is equally distributed among the tested people increasing the number of tests does increase the number of cases but not the percentage of tests coming back positive.

If not only the number of cases is increasing over time but the percentage of tests coming back positive as well the pandemic is spreading. That is what is happening. It is also explained already in the article.

Bob boder
Reply to  Ron
July 14, 2020 8:33 am

Except that is not what is happening the number of positive tests coming back is shrinking not growing. positive test coming back are in the 7% range they were as high as 20% at one point. we are testing about 800,000 people a day and getting about 50,000 positives. when we were testing 100,000 a day back in may we were getting 20 to 30,000 positive.

Reply to  Bob boder
July 14, 2020 10:44 am

You have to look by state. This pandemic is organised locally. Texas e.g. has gone from 4% up to 16% from May to now. The test number has only doubled in that time.

Bob boder
Reply to  Ron
July 14, 2020 12:01 pm

None sense, if that’s the case then just compare NY in April and May to Texas now, NY death rate 10 to 15 times Texas now, infection rate for NY totally unkown because testing couldn’t keep up but clearly sever case much higher, likely mild cases 10 times Texas rate, with 2/3 the populations. NY and NJ still have almost as many deaths per day as Florida and Texas. There are going to be surge areas in the country that’s definite but over all the high rate of positives now compared to April/May is all about testing.

Reply to  Ron
July 14, 2020 12:13 pm

Perhaps what is going on in TX and elsewhere is the same as what’s going on in FL.

FOX 35 INVESTIGATES: Florida Department of Health says some labs have not reported negative COVID-19 results

Reply to  Ron
July 14, 2020 1:34 pm

Per the above link

FOX 35 News went on to speak with the Florida Department of Health on Tuesday. They confirmed that although private and public laboratories are required to report positive and negative results to the state immediately, some have not. Specifically, they said that some smaller, private labs were not reporting negative test result data to the state.

Why? Is there some hanky panky going on? Incentives to withhold data to inflate infection rate?

Reply to  Ron
July 14, 2020 3:12 pm

…but over all the high rate of positives now compared to April/May is all about testing.

You seem to not understand why percentage and total number of test are not directly correlated.

If number of tests and number of positive cases increase but percentage of positives stays the same the pandemic is stable.

If number of tests and number of positive cases increase but percentage of positives goes down then the pandemic is going down.

If number of tests and number of positive cases increase but percentage of positives goes up the same the pandemic is accelerating.

Specifically, they said that some smaller, private labs were not reporting negative test result data to the state.

Irrevalent if the number of not reported negative cases is not 3/4 of all negative cases. Otherwise you cannot explain the increase from 4% to 16%.

For Florida half of all negative cases need to be not reported to explain the increase of the positivity rate from 5% to 10%. It’s not plausible that smaller, private labs could have that impact.

Data for Florida:

Reply to  Ron
July 14, 2020 3:18 pm

“If number of tests and number of positive cases increase but percentage of positives stays the same the pandemic is stable.”

I have to add here that it means its development is stable. It can of course be an explosive exponential growth if the positivity rate is high.

Reply to  Ron
July 14, 2020 4:20 pm

This report says it was over 50 labs that reported percentages near 100%. No mention of size, but size really doesn’t matter; the cumulative total they do does.

Florida Labs Acknowledge “Major Errors” After Reporting Positivity Rates Of 100%

Reply to  Ron
July 14, 2020 5:59 pm

Number of people tested matters. Even if 50 labs reported falsely positives if each tested 5 people it doesn’t matter. If each tested 100 it matters but only for daily cases.
As a one time event it still wouldn’t matter for the increase from 60k active cases from mid June to 250k active cases now. Just negligible. You would need constant false positive reporting at a significant rate to matter.

At the moment there is no evidence that this is happening. In fact, daily deaths are increasing now, 3-4 weeks after cases increased as would be expected.

Until daily cases will plateau or start decreasing that trend will continue. Too many examples worldwide now that show this pattern. There is no reason to believe it would be different this time.

Bob boder
Reply to  Ron
July 14, 2020 4:09 pm


You don’t seem to understand, for the country the percentages are going down, the deaths are going down, the number of positives are going up. It’s not getting worse period. In Texas and Florida it is worse but no where near as bad as NY and NJ 2 months ago, son it still better then it was. No matter what BS you try to spin it with.

Reply to  Bob boder
July 14, 2020 5:34 pm

Deaths are already going up. Don’t let yourself be blinded by the reporting lag time of the CDC. Cumulative number from states already show the trend.

If you look at deaths/pop NY and NJ are nearly twice as bad as Belgium which is by far the worst performing country worldwide. Don’t fool yourself just bc the pandemic has not reached every corner of the US yet.

The more you test the closer you get to the IFR meaning your CFR is decreasing steadily so it’s easy to predict it will never be “as bad” as in NY cause at that time there was hugh undertesting. Though the serological study suggests an IFR of over 1%.

Steven F
Reply to  Bob boder
July 14, 2020 6:13 pm

In the last 15 day texas and florida have reported 1000 deaths each. During that same period new york reported about 100 deaths. Death rates are increasing in most states. Testing rates in all states it pu but very few states are showing declines in deaths. The state that has reported the most deaths in a single day is Florida. Yexas is close behind. More deaths than New York has ever seen in a single day.

Reply to  Steven F
July 15, 2020 3:24 am

@Steven F

More deaths than New York has ever seen in a single day.
NY had 1000 deaths per days at peak times. No other state is there yet.

What is troubling is that NY had also 10k new cases per day at peak times when their testing finally caught up and they got the positivity rate going down but which nonetheless translated later still into couple of 1000s deaths per day.

It might be less than in NY this time (demographics of infected one factor), also bc the treatment got better (anti-coagulants, dexamethasone, remdesivir, proning etc.) but there is just no way a very huge number will not translate into a huge number even with a small percentage.

Reply to  Steven F
July 15, 2020 3:24 am

Ups Blockquote gone wrong…

Bob boder
Reply to  Steven F
July 15, 2020 7:19 am


I have no idea where you got that from.
NY was recording almost a 1000 deaths per day at one point, they have over 34,000 dead total, Texas has 10 % of that.

Reply to  Chris Wright
July 14, 2020 5:32 am

Studies have related normal flu dropoff in warm weather to humidity. Interestingly enough, it is Absolute Humidity, not Relative Humidity that provides the best statistical fit, > .9 R^2
Makes sense, if the transmission vector is aerosol, as the particles would tend to pick up moisture, become heavier, and settle out of the air streams.
Same mechanism “could” apply to SARS-CoV2. Where is the science! As a practicing professional engineer, I am horrified at the lack of simple experiments that would show N95 “good,” fabric masks only good for sneezes or coughs.

Carbon Bigfoot
Reply to  Enginer01
July 14, 2020 6:42 am

Definition of Relative Humidity:
The sweat you develop on your balls while screwing your sister-in-law.

Reply to  Carbon Bigfoot
July 14, 2020 9:54 am

Waka. Waka.

Reply to  Chris Wright
July 14, 2020 7:12 am

Deaths is a confounded variable now. Treatment regimes from antivirals to anticoagulants, prone positioning of patients with moderate respiratory failure, and marked change in ventilator settings away from typical ARDS treatment have all improved survival in severe cases.

Just like with the ever-changing chaotic climate, doing science on an evolving process like covid requires respect for uncertainty.

That being said, the air conditioning factor in the recent spike in cases makes sense.

July 14, 2020 3:58 am

These people are as simple-minded as climate alarmists. Oh that’s right, it’s the same people.

Reply to  richard
July 14, 2020 11:27 am

Good article, but do others find white text on black background painful on the eyes?

Reply to  Scissor
July 14, 2020 6:51 pm


July 14, 2020 4:10 am

For a climate blog I would like to add that one should emphasise recirculating air is probably the culprit next to confined spaces.

This lowers energy consumption but increases viral load over time if no effective viral filter/sterilization system is installed (wich is definitively not always the case).

So again, the pandemic clashes with the green agenda. Will be interesting to see how this turns out.

July 14, 2020 4:17 am

I could pull up my several posts here (WUWT) and numerous posts on, or my eMail to Gov. DeSantis, but let me repeat:
1) Aerosol transmission by formation of Brownian Motion sized droplets is plausible, if not prove [[[Where’s the science? It should be here by now!]]]
2) high velocities thru the larnyx (singing, yelling at sports fields) are the greatest risk (Fits some data)
3) ASHRAE addresses some of these issues. Not enough replacement air. HEPA filters in hospitals.
4) Beaches and parks should have never have been shut down, but to-friendly activities should have been advised against. Can you understand the extreme (???) 0f Florida not cancelling spring break?
5. Siting in a restaurant with recirculated air blowing in your face is like Russian Roulette.
6. Satellite photos show extreme hospital activity in China in !SEPTEMBER!! 2019
I could go on, pushing hydroxychloroquine+Zinc+Zpak as soon as symptoms show, or before…but this group has heard it all

Tom in Florida
Reply to  Enginer01
July 14, 2020 6:00 am

Funny how they did not report any tracking of the spring breakers who were supposed to spread the disease all over the Country. Perhaps there was none?

Carbon Bigfoot
July 14, 2020 4:28 am

As some have noted most residences that utilize window units recycle room air with little or no fresh air exchange as that is all that most people can afford. Necessary make-up (fresh) air was virtually eliminated by ASHRE,, in the oil embargo days in view of the cost of energy particularly in commercial applications.
Never been a fan of ceiling diffused air in either a heat or cool application, but the common method for most commercial/industrial applications was a roof top HVAC with self contained compressor condenser for cooling and if available propane or natural gas burner for heating and standard fiberglass filters or roll filtration system. A plenum with under roof ductwork for distribution of diffused conditioned air was the cheapest alternative and avoided more sophisticated water systems with boilers, chillers and distribution piping and controls such as installed in hospitals, chip manufacturing and incorporated HEPA filtration.
Restaurants are problems unto themselves with enormous cooking ventilation issues, latent heat design loads which consumes much electricity adding advanced filtration would close many eateries because of the costs and the regulations that would ensue.
I view this Scamdemic as a contrived experiment. I wonder if the first wave of soldiers to hit OMAHA BEACH knowing that most expected to die would view you panty-waste cowards afraid to dine in a restaurant to avoid catching the flu to be worth their sacrifice.

Russell Klier
July 14, 2020 5:00 am

Remember Legionnaires disease…. It was affiliated with ventilation systems too I think.

Carbon Bigfoot
Reply to  Russell Klier
July 14, 2020 6:40 am

Good point Russell. That issue was the direct result of a lack of maintenance of a Cooling Tower in a Philadelphia Hotel. Many older high rise buildings were built with complicated HVAC systems as alluded to in my previous comment. Unfortunately Owners of buildings are not fastidious in appropriate maintenance and either hire incompetent permanent maintenance or subcontractors because it is too expensive to hire competent people. Regulations of these HVAC systems are either non-existent or are not enforced, as it is cheaper to face lawsuits for injury or death than to do routine maintenance The 70s energy crisis and buildings constructed in a too ” air-tight” design led to what was termed in the business as ‘SICK BUILDING SYNDROME”. Air-to-Air Exchangers solved most issues.

Reply to  Russell Klier
July 14, 2020 6:46 am

This should be something that can be easily teated and experimented with, actually doing hard science analyzing the colder, dehumidified air output of all different types of A/C for virus and bacteria spread. I sometimes use a swamp cooler, whereby I put I chunk of ice/cold water into a tank and a fan just blows a bit cooler air through it. These are are probably safer, just due to blowing local humid air, which provides some evaporative cooling for some comfort. I suppose if there are any virus’ available floating around temporarily in the air, the fan also does some air mixing and spreads everything available around.

The HVAC business is about to get an upgrade in engineering and safer operation, which is good. I have always thought (and seemed to get sick more often when in an A/C environment) that just suffering a bit more in the heat is better than than enjoying the cooler drier air. A dehumidifier might be a better use, to not suffer the mugginess of a hot climate which is what makes me feel so uncomfortable.

Reply to  Earthling2
July 14, 2020 10:28 am

My guess is it’s the drier air drying out the sinuses that makes one more prone to infection.

Reply to  icisil
July 14, 2020 6:27 pm

bingo. finally someone gets it.

Reply to  Russell Klier
July 15, 2020 7:11 pm

The first Legionella outbreak was bred in an AC evaporative cooling tower. This is where hot water from the AC condensers was sprayed into airflow so that evporation would cool the water. The water mist from this process carried the bacteria to where it could be inhaled.

Jeff Id
July 14, 2020 5:19 am

I’ve been spamming threads with this for months. I now think it must be behavioral. Before the disease was very prominently up north:

I thought sunlight would help a lot, then cases boomed in the south but North looks pretty good. Now the north is starting to get worse. I now think it is because we are going indoors due to weather. Too cold or too hot, we do the same thing and transmission risks increase. Remember during the height of this, when NY reported that 66% of new cases were from quarantined people.

July 14, 2020 5:25 am

OK, late to the party, two people already brought up Legionnaires. Large air circulation systems which are not frequently and thoroughly cleaned are a problem, not just germs/viruses, mold and allergens build up in these systems, along with just plain dirt. Cleaning these systems is a huge pain in the a$$ and very difficult and the majority of them only have fiber/cloth filters which are changed far less often than they should be. Just because it has the words “hepa filter” on does not mean you can leave it in twice as long.

Is all this helping spread Chinese Disease? Very likely, it damned well does not help to be recirculating dirty air, whether it is warmed or cooled. A change in prioritizing maintenance of indoor air systems is definitely needed, Legionnaires showed us that a long time ago.

Tom in Florida
July 14, 2020 5:49 am

As with masks, air filters have a range of effectiveness. MERV 13 or FPR 9 will trap particles that carry virus, anything less is a waste of money. As with masks, most people are clueless about this and go for the cheapest product still thinking it will work.
Also, why are stats always given by states’ boundaries? Because it is easier? Large states, such as Florida, have concentrated areas of COVID. The 3 SE counties, Palm Beach, Broward and Dade account for almost half the cases. Add in Hillsborough (Tampa) and Orange (Orlando) and you get close to 70%. The rest of the State is doing OK.
Unlike California, New York and Michigan, Florida’s Governor is not issuing a one size fits all order, he is allowing local government to make these decisions depending on their situation.

July 14, 2020 5:50 am

If it comes out of the marxmedia/dopacraps, you can bet it’s a total fabrication.

July 14, 2020 5:56 am

Covid launched in the Australian summer and it was then touted as one of the reasons the virus was less severe there. Aussies are no less addicted to aircon than Americans.

Just Jenn
July 14, 2020 6:05 am

This is all conjecture until we have a reliable antibody test.

All I read are “positive cases are up”, “highest 1 day spike”, “virus cases up”. Testing positive is not a death sentence–no matter how many anecdotal stories are being told.

I want the truth for once. Just once. Non varnished/slanted truth. I can do basic math and get a percentage, hell I could pull all the data into scatter plots, I could analyze that data—numbers aren’t the problem here…the actual DATA is the problem here. It tells us nothing except that increased testing means finding more positives. But positives in which stage of the virus? Do the people even have symptoms? Do they develop into something more than just carrying around the virus…or are the tests picking up antibodies? Are they? Nobody has said. How are these tests set up? What viral load are they testing for? Because in the realm of virology, viral load is the key component to developing a disease that could be fatal.

These are real questions that are not answered, are glossed over, are slanted to being either conservative/liberal/right/left…no they aren’t. They are real questions that need to start being ASKED. And asked properly of anyone spouting “expertise”.

The virus is not a superbug ok? Its a coronavirus–one of millions I’m sure (although that number IS pure speculation) that we’ve identified so far. But to what real danger does this virus do? We have evidence, we’ve seen what it can do in a trapped population and it did very little actually to what it could have done if it were as fatal or as infectious/fast moving as hell even a nonsuperbug can be. Take norovirus for example–1 person can infect 8-12 people, damn high communication rate..and it makes you sick to your stomach…well what happens if you don’t treat the symptoms? You could expire of dehydration due to vomiting and diarrhea a very real possibility. Tuberculosis is another one–extremely contagious and chronic disease that can k&11 you and we don’t really even test for it anymore except when it is required. Tuberculosis ck*lls hundreds of thousands of people a year. A YEAR and we have a vaccine for it but funny how it’s not scary because we know about it.

We need to collectively calm the f&ck down, take a step back, take a deep breath, lock the door, tell the Karens’ to go home and re-analyze what is really going on here. And then collectively analyze what we know from past experiences with coronaviruses and viruses in general that are in that realm of communicability and fatality within that type of viral group. Stop comparing apples to oranges. Coronavirus is not the flu–because it’s fatality is not affecting young children who are susceptible to the flu. It’s attacking the older generation and those with comorbidities. THIS we know. We have number for it. Let’s leave off the older generation for now and look at those younger with comorbidities–why is it fatal to them? At what threshold? And which ones at what extremes? If you have slightly higher blood sugar is that a risk if you get coronovirus? If so, how high exactly? What about those that suffer chronically with other comorbidities–where are they on the scale?

And finally–prevention. Prevention of the spreading—is this even possible in our world today? We know it spreads through droplets from sneezing and coughing. BUT is all the massive sterilization going on actually hindering a natural defender of the virus? Are we decimating the good bacteria and fungi with the bad and do some of those actually act as protective barriers to catching the virus and dispatching it before we even touch it in the verve to be sterile? What does temperature/humidity do to the virus? We know this already– anything above 75 degrees F and about 50% humidity. Sunlight destroys it. So….open a window and turn the A/C up (conversely, turn up the heater and get a humidifier). How freaking hard is that anyway? Leave a door open in an office building and turn the AC up to 76. We don’t need to live in 72 degrees F or lower (grocery stores, I’m looking at you!). Bug screens a problem? Well you don’t need to retrofit a business door–go get a Magic Mesh or something like it…great little invention, works well if you can put it up that is. If not, you can do the same thing with screening and magnets. What about those going into Winter? Same–turn up the heat and get some humidity into the building.

Someone upthread said something about people not used to being uncomfortable–well yea. They aren’t. But it’s not going to hurt anyone to be uncomfortable…..we already know this, so now it’s time for real action and not more fear mongering. Take a step back, analyze the real data and act accordingly. Stop with the anectodal evidence and get to the real problem here–we have a virus in the population that for a majority of that population isn’t fatal. So isolate those that are susceptible and let the others go to develop an immunity and in so doing destroy that viruses ability to spread. Stop the spread is about letting people get exposed….those that have reduced risk of getting out of their taxes.

Reply to  Just Jenn
July 14, 2020 6:51 am

“How are these tests set up? What viral load are they testing for? Because in the realm of virology, viral load is the key component to developing a disease that could be fatal.”

Every manufacturer sets their own upper limit number, which varies from about 30-45, so there is no consistency and, consequently, no accuracy; you could test positive on one manufacturer’s test and negative on another’s (not to mention the same can happen with the same test from the same manufacturer). The upper limit is the number of iterations required to detect the targeted RNA sequence. Around 35 is generally considered to be the upper limit, but some manufacturers go as high as 40-45. It’s anything but scientific.

Viral load cannot be determined from PCR tests. It’s simply a manufacturing technology to amplify a very small signal, so to speak.

Reply to  icisil
July 14, 2020 10:58 am

The upper limit is the number of iterations required to detect the targeted RNA sequence. Around 35 is generally considered to be the upper limit, but some manufacturers go as high as 40-45. It’s anything but scientific.

Wrong. That is not how that works. The threshold is set by a calibration curve of known template concentrations and negative controls. 35, 40 or 45 has nothing to do with it.

Because in the realm of virology, viral load is the key component to developing a disease that could be fatal.

That is too over-simplistic.

Viral load is important for the initial infection, yes. If the exposure is below a certain threshold you will not conduct the disease. Even true for HIV. Then there are viruses where the viral load further determines how bad the disease will be. But then there are viruses where that doesn’t matter at all. Once above the threshold and infected it doesn’t matter how much above threshold it was.

Dodgy Geezer
July 14, 2020 6:14 am

“A worsening epidemic is signaled (sic) by a higher percentage of positives, assuming there is widespread testing…”

As Willis says – first UNDERSTAND the data. That means:

1 – confirming that there is widespread testing
2 – confirming that no other variable which might be responsible for increased percentages was altered over the timespan being considered.

Given that all sorts of things are being changed on a daily basis as a response to this virus, I cannot see how you can be sure of 2) above – let alone correct for it…

Interesting hypothesis, though. ideally, we would take two sample restaurants and compare with and without A/C…

Robert W. Turner
July 14, 2020 6:18 am

Spreading the virus during the summer is a good thing. Herd immunity will be reached faster and more cases during the winter months equals higher CFR. If I don’t catch this newest cold virus winter, I will be eating salmon, shrimp, cod, mushrooms, and eggs far more often than normal.

Reply to  Robert W. Turner
July 14, 2020 11:09 am

I’ve seen two reports in the past week that indicate anti-bodies for Covid19 only last a couple of months after the infection goes away.

Ian W
Reply to  MarkW
July 15, 2020 12:28 pm

True they do.
The adaptive immune system doesn’t carry on generating antibodies for every disease it has ever encountered. But once the body is reinfected the adaptive immune system is no longer naive to that infection and will rapidly generate antibodies against it.

July 14, 2020 6:22 am

Another possible factor, as discussed elsewhere, is the wildly increased testing. I’ve heard the number of tests is approaching 1 million/day in the US. (That seems like a lot, I’d have to confirm.) This will find plenty of “asymptomatic” cases, past cases, or even remnants of other coronavirus issues like the common cold. Deaths are dropping, which is the data-point worth watching.

Reply to  PaulH
July 14, 2020 9:47 am

In many states (including the hotspots), the positive rate is going up at the same time as testing is increasing. If the only cause of more cases were increased testing, then the positive test rate would be flat or going down. So no, this is a real increase in the population’s infection rate.

Reply to  mcswell
July 14, 2020 10:11 am

Are death rates increasing? If so, where?

Reply to  Derg
July 14, 2020 11:11 am

Deaths are a lagging indicator. First it takes awhile to go from sick to dead, then reporting is often delayed by days to over a week.

Reply to  MarkW
July 14, 2020 2:33 pm

Are death rates increasing?

If yes, where?

July 14, 2020 6:56 am

I agree with the premise of more A|C as one of the major causes of increased spread especially in the Southern hot States.

However, one big potential cause not often discussed is the an migrant worker influx that is estimated at 3 million. Florida, Texas, California are all big destinations for migrant worker. In my home State of Washington, the major outbreak here is in Yakima, Benton, and Franklin Counties, all lower population farming communities. Add in the cramped quarters and you have a recipe for Covid spread.

You only have to view Worldometer COVID-19Tracker to see Mexico, Central and South America have a major Covid outbreak. Hence my theory that migrant workers brought it North and A/C helped it’s spread. Add in reopening, protests for weeks with massive crowds and combined these all result a massive increase in Covid-19.

July 14, 2020 7:05 am

Flagstaff, in northern Arizona, is at a higher altitude than most other populated areas of AZ, and therefore cooler:
(or look at recent weather reports for Flagstaff). If the spread is due to the use of A/C, then cases should be lower there. As you can see here, that’s not true:
I conclude that it’s not A/C, it’s the stupid people who run around in public without masks.

If for some reason that URL for Arizona cases by zip code doesn’t work, then use this one:
and click on “zip code”. It’ll open in a new browser tab.

Mark A Luhman
Reply to  mcswell
July 14, 2020 2:44 pm

IF you think a mask will protect you and prevent the spread, do you want to by a bridge in Brooklyn? Show me the science.

Reply to  Mark A Luhman
July 14, 2020 7:53 pm

GIYF, but since you’re too lazy, try this:

(and note that the study was done long before anyone heard of covid-19)

If you want more science, I suggest you do a web search.

BTW, wearing a mask may not protect me much, but it does help prevent the spread.

Steven F
Reply to  mcswell
July 14, 2020 6:27 pm

You are forgetting that most people in Phoenix go north in on the weekends and holiday and vacation to get away from the heat in Phoenix. And with these people comes covid 19 .Right now the virus is spreading from city to city due to road travel. In february the virus was mainly spreading due to air travel. But today very few people are traveling by air.

Archibald Tuttle
July 14, 2020 7:14 am

Certainly a plausible hypothesis and makes a lot of sense, but on the moving from correlation to causation point, this study from 2006 found no live virus on HVAC filters. Is it conceivable that live virus particles were passing through the filters and never deposited or that once deposited they break down quickly but live virust that passes the filters is still being ciruclated? And of course this doesn’t account for what circulated air is doing regarding moving droplets/aerosols around in the space by the force of its discharge from outlets.

Bacteria different story in this study, and see legionella, albeit it was hardly praticle to shut down all the HVAC in the US for the very occasional outbreak.

Indeed, my greatest awareness of work on legionella from within the HVA industry where I sit is the flushing of domestic hot water systems in institutional settings, usually with very hot water. Pretty crazy expense going into this at the moment and i’m not sure what success. Over the long hall it favors forward located hot water systems that make it on demand close to the outlet where it will be used. Although the research on legionella has found that lukewarm closed water systems are good breeding grounds, it hasn’t confirmed a spread mechanism. Research on showering in hospitals for instance came up empty in this regard. Unlike corona virus, legionella is just everywhere but its pathogenic qualities emergence on amplification in numbers and spread mechanism (ironically this greatly implicated outdoor air conditioner condensors with open water cooling and building air intakes that pulled in aersolized legionella from those sources IIRC, and moving intakes and treating the water were low hanging fruit).

Norman Blanton
July 14, 2020 7:51 am

It’s hot, the mask is uncomfortable and the heat makes it worse….

I have to wonder if the condensation on the cooling coil might wash the virus out of the air. though there is a large bypass factor…

need to make sure we are talking about large buildings with A/C, I would doubt that home A/C is a factor, you are already infected or someone in your family, a lot of ways other that airborne to spread the virus.

July 14, 2020 8:12 am

The connection between the spread of Wuhan and indoor a/c was suggested by one of our AK outdoors reporters (Craig Medred) a month ago.

There is a possible solution – UVC is used to sterilize both surfaces and volumes of air (medical settings, aircraft interiors, subway interiors). Might be time to look at installing UVC in ceilings of high rooms, pointing the lights sideways and using a ceiling fan to blow air thru the light. Also possible to install the lights in a duct not unlike we do with humidifiers.

Too much hand-wringing these days and not enough creative thinking. Fun part about installing UVC is that it will work against airborne transmission of any other virus or bacteria.

Only thing I don’t understand are costs. Medical grade units are in the thousands of $ (US). Commercial units are in the tens of $ (US). Cheers –

Ian W
Reply to  agimarc
July 15, 2020 12:35 pm

The Chinese study of a restaurant with air conditioning showed that it was the flow of air from the air conditioning blower – over an infected person that carried on over two more tables where most diners became infected. A table with diners that was out of the flow of air from the infected no-one was infected.

You would probably get a similar effect from overhead fans except that the air conditioned air is cold and dry which is more likely to spread the virus than blown room temperature/humidity air. Also a ceiling fan is blowing down and not across diners.

M__ S__
July 14, 2020 8:41 am

Isn’t humidity the key driver of water droplet borne illness?

Wouldn’t the relative humidity change by AC be responsible?

Maybe just turn the AC down to raise the humidity

Bob boder
July 14, 2020 8:47 am

NY and NJ are still having almost as many deaths per day as Texas and Florida. Texas has about a 50% higher population than NY and about 10% the number of deaths that NY does. Maybe that will change but i don’t think by that much.

Janet L. Chennault
July 14, 2020 9:34 am

If I wanted to test this hypothesis, I would not make a graph. I would set up an experiment and test the AC filters for virus particles.


Reply to  Janet L. Chennault
July 14, 2020 10:31 am

The filters most likely would show nothing. They’re too coarse to stop virons, let alone particles.

Tom in Florida
Reply to  Janet L. Chennault
July 15, 2020 4:57 am

Air filters are already rated for their filtering effectiveness against many different things including smoke and virus carrying particles. Read the label.

archibald tuttle
Reply to  Janet L. Chennault
July 16, 2020 7:01 am
July 14, 2020 10:05 am

Bodor, not sure where you’re getting your numbers from, but if you look at the charts here: (you can substitute ‘new_york’ etc. for ‘florida’), you’ll see that in the past week, deaths per day in Florida have been between 35 and 120, while deaths per day in New York (state) have been 5 and 20. Texas: between 43 and 105. New Jersey has been higher than New York, a little less than Florida, Texas and Arizona (and a smaller population than those states, so the death rate is pretty high there).

At any rate, NY is NOT “still having almost as many deaths per day as Texas and Florida.”

Reply to  mcswell
July 14, 2020 11:46 am

The Southern states are still way behind NY and NJ in terms of death rates. They will catch up to some extent unfortunately, but likely will end up much better because susceptible people are being better protected.

Reply to  Scissor
July 14, 2020 12:23 pm

Possibly that, but doctors not rushing to intubation is certainly lowering mortality. It’s really turning into a movement. There are still holdouts stuck in the obsolete paradigm, though, unfortunately.

July 14, 2020 10:21 am

The exhaled human air when it comes out of the mouth is approximately characterized by T = 35 ° C (temperature T in ° Celsius) and Ur = 80% (Ur=relative humidity).
If the exhaled air finds an external environment with the same temperature and humidity conditions, the virus has a 1 chance of infecting a person.
In fact 4.42-2.24-1.91+0.84 is about 1. See equation DX=4.42-T/15.6-Ur/41.9+(T*Ur)/3320 that you find in .
In a room with air conditioner we can to measure T=20°C and Ur=30%; applying the previous equation, DX=2.6, that is, the possibility of infecting a person at a distance of 2.6 times greater.
That’s why air conditioning increases the chance of getting infected.

Bob Rogers
July 14, 2020 10:23 am

In order for any of these comparisons to have any validity, would it not be necessary for there to be uniformity of testing?

Ed Powell
July 14, 2020 11:52 am

A confounding variable, which we see here in Northern Virginia, is the spread among Hispanics far out of proportion to their fraction of the population. One hypothesis I heard about this is that Hispanics are more likely to live in multigenerational households (kids, parents, grandparents, even great-grandparents) than whites, blacks, or Asians. These living arrangements are the prime suspect for why the fraction of positive cases in NoVA that are among Hispanics is >60%, while they only make up about 15% of the population here. What else does Arizona, Florida, and even Mississippi have as well as A/C? That’s right, lots of Hispanic households. So a proper analysis would control for this aspect as well as just temperature and humidity.

Russ Hickman
July 14, 2020 1:50 pm

I live in GA and I believe that a reason for much of the increased cases is due to migrant farm workers as case growth has been highly localized and is not uniform across the state. Georgia is at peak harvest right now for many of its most important food crops- peaches, onions, blueberries – and cases have grown substantially in the areas where those foods are grown. The state also reports cases by county of residence and the number 3 county for cases and number one for case growth is “non-Georgia resident”, as well as cases growing most in the 18-40 age group. GA is also by far the largest poultry producer in the US and cases have grown substantially in those plants as was seen earlier in meat processing plants in the Midwest. As harvests began and these workers (mainly from Mexico) moved into the these areas cases began to rise. I also have a home in East TN and we had a similar situation in early June when our largest strawberry producer had to shut down harvest and sales when it was found his entire crew of migrant workers were infected (most asymptomatic). Their 2-week quarantine caused him to lose most of his crop.

Reply to  Russ Hickman
July 14, 2020 3:30 pm

That makes sense.

Reply to  Russ Hickman
July 14, 2020 6:38 pm

well if you did contact tracing you would know.

and not have to speculate


July 14, 2020 2:17 pm

Hypothesis is that low mortality strains are becoming dominant. The high mortality strains make people ill with symptoms, many end up in hospital or at least isolate at home which reduces chance that the strain spreads. With low mortality strains there is little isolation as many are asymptotic or have mild symptoms thus they spread easier. The low mortality strains effectively then become vaccine for high mortality strains.

Patrick MJD
Reply to  Stevek
July 14, 2020 7:56 pm

I read the test criteria for COVID-19 was derived from a dataset of 8-10 victims who were already very ill. The other risk groups were not included.

Sky King
July 14, 2020 3:18 pm

Aircon has been posited for the difference in infection rates of Singapore versus say the Philippines in SEA. In the Phils most people don’t have aircon at home because of the expensive power.

July 14, 2020 3:57 pm

There’s such a thing as an “all year” virus you know. Present and spreads all year. COVID-19 is apparently one of those viruses. Why keep pretending your pet falsified theory about why COVID-19 should go away with Summer isn’t really wrong? Clearly that theory should have been abandoned last month. I confirmed by early to mid April that the data available showed that spreading was faster in warmer counties in the southern hemisphere. It was about 25% faster spread than in the colder northern hemisphere countries, within 14 days of data.

Did no one else even bother to check the actual spreading rate numbers for both hotter and colder countries?

Why didn’t you, if you feel so confident your theory is correct? Well it isn’t correct, I found from analyzing the daily spreading data that the opposite was true, it actually spread about 25% FASTER in the hotter conditions, in poorer (non western) countries.

Here’s the tabulation of results from March 29th through to April 11th 2020, showing the ~25% faster spreading within the (then) hotter countries, as compared to the spreading observed in the colder counties:

comment image

The only reason it took longer to build the numbers up from a very low level in those developing countries is because they had far fewer large-scale links to the industrial production heartland of central China, early on in the disease. And by the time this data was being gathered a global isolation process had already begun in almost all countries.

But the West had extensive direct links to the area, so the virus spread quickly in the colder western countries, from a lot more carriers being present. Which resulted in the growth in the west in colder conditions becoming extremely quick.

But despite the global isolation policies, the spreading was still about 25% faster anyway in the hotter countries. There was ZERO EVIDENCE that heat or humidity were suppressing it, quite the opposite.

But this falsified theory that Summer SHOULD slow it down, persists all the way into July, in some people’s minds.

BTW, the hotter southern hemisphere countries listed were generally poorer countries where copious air conditioning was unlikely to be present or affordable, let alone a credible cheap electricity network, needed to feed such air cons with the necessary extra electron production and transmission load.

Time to let this go, and look at the actual numbers themselves, and stop just slagging them off as “irrelevant”, and tell us nothing. Well if that’s your attitude, and you don’t look at the numbers, yeah, they can tell you nothing, so you’ll chase your tail around for 3 months.

Reply to  WXcycles
July 14, 2020 5:43 pm

Is the death rate increasing too?

July 14, 2020 5:25 pm

Whilst the spread of the virus since opening up has been most active in Republican states they are still way below the deaths per million in Democrat states. I feel physically ill when I hear Cuomo from New York giving advice to the Republican states about how to handle the rising number of cases. The media and the democrats are spinning the circumstances for purely political purposes and there is no doubts the Democrats hope that the Corona virus will achieve what the hoax Russian collusion story couldn’t.

Reply to  Zigmaster
July 14, 2020 5:44 pm

Cuomo should be charged for killing the elderly in NY.

Dr. Doom
July 14, 2020 7:34 pm

Only one mention of mosquito in the comments ?!?

Of course, it’s the mosquitoes and or the fleas!

Patrick MJD
July 14, 2020 9:45 pm

Interesting video.

July 24, 2020 6:20 pm

I have been following a site called worldometer as a source of global, national, state and county covid data. The charts on state level daily new cases (positive test results) are informative.
Months ago, New York, New Jersey, and Illinois were hit by sky-high numbers of new cases. The virus had spread through the state population before public health measures had been taken and was in community spread. Nevertheless, cases peaked and then went into a precipitous decline. These states have not had an issue since. Why? I have come to the conclusion that preventive measures are simple and effective. Masks, handwashing, social distancing, avoiding crowds, so that compliant people are not in the population available to the virus. The real “herd” for herd immunity consists mainly of stubbornly non-compliant people who won’t wear a mask, insist on hanging out in crowds, and don’t wash their hands. We know the actual cases are 6 to 24 times greater than reported. That is a lot of non-compliant people. NY NJ IL have a kind of herd immunity. But other states, CA, FL, TX, AZ, launched very effective shutdowns early on. This meant people didn’t get sick and herd immunity did not build. Since the reopening, the predictable occurred. The infection curves for these states now look just like New York, at least on the upside. Arizona new cases are beginning to decline, steeply. Texas and Florida are close behind. California, of course, remains a mess. My prediction is that if we just go back to work and let non-compliant people get sick, new cases will fall off dramatically nation-wide within weeks. An FDA approved vaccine is six months to never away. It costs $2 trillion a month to shut down. Better to just wear a mask, protect the sick and elderly, and get on with life.
California has a special problem in that it has been reported that large numbers of Mexicans with covid are entering southern California illegally for medical treatment at state taxpayer expense. If so California can be expected to have the problem longer.
Otherwise I think the story here is that shutdowns only delay the inevitable. The best course of action is to take public health protective measures and let the virus spread among the unwilling until it burns itself out.

Reply to  Jim
July 25, 2020 4:56 am

Let it spread among everyone, protect high risk groups, elderly and sickly chi’drens, and the rest of us move on with our lives. Oh, and this flu strain was spreading LONG before any “experts” started spewing the idiocy.

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