NASA Satellite Data Show 30 Percent Drop In Air Pollution Over Northeast U.S.

From NASA

Over the past several weeks, NASA satellite measurements have revealed significant reductions in air pollution over the major metropolitan areas of the Northeast United States. Similar reductions have been observed in other regions of the world. These recent improvements in air quality have come at a high cost, as communities grapple with widespread lockdowns and shelter-in-place orders as a result of the spread of COVID-19.

before
Average concentration in March of 2015-19, Credits: NASA
after
March of this year. Credits: NASA

Nitrogen dioxide, primarily emitted from burning fossil fuels for transportation and electricity generation, can be used as an indicator of changes in human activity. The images below show average concentrations of atmospheric nitrogen dioxide as measured by the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite, as processed by a team at NASA’s Goddard Space Flight Center, Greenbelt, Maryland. The left image in the slider shows the average concentration in March of 2015-19, while the right image in the slider shows the average concentration measured in March of this year.

Though variations in weather from year to year cause variations in the monthly means for individual years, March 2020 shows the lowest monthly atmospheric nitrogen dioxide levels of any March during the OMI data record, which spans 2005 to the present. In fact, the data indicate that the nitrogen dioxide levels in March 2020 are about 30% lower on average across the region of the I-95 corridor from Washington, DC to Boston than when compared to the March mean of 2015-19. Further analysis will be required to rigorously quantify the amount of the change in nitrogen dioxide levels associated with changes in emissions versus natural variations in weather.

If processed and interpreted carefully, nitrogen dioxide levels observed from space serve as an effective proxy for nitrogen dioxide levels at Earth’s surface, though there will likely be differences in the measurements from space and those made at ground level. It is also important to note that satellites that measure nitrogen dioxide cannot see through clouds, so all data shown is for days with low cloudiness. Such nuances in the data make long-term records vital in understanding changes like those shown in this image.

For more information on NASA’s air quality research, visit airquality.gsfc.nasa.gov.

The visual in this article can be downloaded at NASA’s Scientific VIsualization Studio. 

59 thoughts on “NASA Satellite Data Show 30 Percent Drop In Air Pollution Over Northeast U.S.

    • This virus is a making us run a very interesting experiment. Will CO2 fall, and if it does will global temperatures. (Solar forcing takes a few hours to act, so does CO2, the lag is a few hours).

    • CO2 levels will fall around mid May – just like they did last year and every other year. So far, still going up, except for the last couple of days maybe.

      If this WuFlu lockdown is still going on in a month I imagine we will see a chorus of ‘look, look we can reduce emissions and affect the CO2 levels’. Ignoring the seasonal fluctuation of 8-10 ppm that happens anyway as the northern hemisphere drifts into Spring.

      But being Spring, even here in the UK, I confidently expect it to also get warmer!

      https://www.esrl.noaa.gov/gmd/ccgg/trends/monthly.html

  1. Yes, the usual environuts and MSM have been trying to push this ‘hallelujah the air is cleansed narrative’.

    I’m not convinced myself, seems that changes of weather/season and wind direction are bigger factors.

    In a highly populated/traffic clogged area of S.England near me, the air pollution monitoring station does show a decline in the period, but it is not at all well correlated to the shutdown date, and the levels have now returned and exceeded those prior – but the shutdown is still very much on.

    • Thanks, MrGrimNasty. Please post a link to the air pollution monitoring site to which you’re referring so that I can see if there’s one near me too.

      Stay safe and healthy, all.

      Bob

        • The change will be minuscule, as we contribute only 3% of the CO2 in the atmosphere. The main source is decaying vegetation, which has nothing to do with humans.

        • Established SSE wind veered N overnight in Brighton, pollutants plunged. Despite European shutdowns, UK air quality is obviously still largely controlled by ‘filthy’ European continental air and nothing much appears to have change in UK or with Europe, air pollution wise.

      • This is not all it is cracked up to be. Even though concentrations are down bottom line is that the concentrations are well below the ambient air quality standards. The data only show relative changes.

        EPA air quality data are available at https://www.epa.gov/outdoor-air-quality-data

        The March 2020 NO2 data are not available at the time of this writing.

        The average of the hourly maximum values for January and February was 31.7 ppb and the National Ambient Air Quality Standard for NO2 is 100 ppb measured as the 98th percentile of 1-hour daily maximum concentrations averaged over 3 years.

        In 2019 the average of the hourly maximum values for March was 40 ppb and the 98th percentile of 1-hour daily maximum concentrations for the entire year was 56.1 ppb.

        Another note is that the values shown (molecules per cm2) cannot be converted to ppb without a lot of assumptions. https://www.researchgate.net/post/How_can_I_convert_the_unit_from_molecules_cm2_to_ppm

        I personally do not subscribe to linear no-threshold health effect models so I do not think a change below the health limits makes a difference especially relative to the costs to the economy making the observed changes.

        • Roger-

          Thanks for your comments. I’ve been out of the mobile source air pollution control business for 20 years, but it was my impression that all U.S. counties meet the NAAQS’s for all the criteria pollutants for some time now.

    • MrGrimNasty – April 12, 2020 at 2:20 pm

      I’m not convinced myself, seems that changes of weather/season and wind direction are bigger factors.

      MrGrimNasty, after reading your posting, with special emphasis on the above, ……. I am now really curious if there was a BIG difference in the “weather and wind direction” in the eastern US during the month of March 2020, ……. than there was for the months of March from 2015 thru 2019?

      To wit:

      Excerpt from article:

      The images below show average concentrations of atmospheric nitrogen dioxide as measured by the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite, ……

      The left image in the slider shows the average concentration in March of 2015-19, while the right image in the slider shows the average concentration measured in March of this year. (2020)

      Like iffen there was a strong “nor’easter” in March 2020 it would have blown that concentration of “atmospheric nitrogen dioxide” to places unknown.

  2. The “pause” in global warming is supposed to be attributable to aerosols reflecting back sunlight. If that’s the case, shouldn’t we be seeing temperatures start to catch up with the climate models?

  3. ‘” Similar reductions have been observed in other regions of the world.”

    yeah right…..that’s why they picked the NE and not China…pollution capital of the world

      • The dates? The gap? Funny smell? MSM/activists carefully selecting/misrepresenting data. Never.

        That contrast is more likely to be mostly the result of a long build up and trapping of pollution under an inversion layer, the topography etc. that was then cleared out by a change of weather (chiefly wind strength/direction).

        With millions of people trapped at home needing to keep warm, the mega-coal power stations would have been working hard and domestic burning rampant – so ask yourself why is there no sign of pollution from that!

        • Strongly agree with you. Strange they use “an average of March 2015 -19 ” and then compare to March 2020. Why no just 2019 vs 2020? ? Very large number of Coal plants have been shut down
          over the last 5 years, Especially in Ohio and PA, NJ has and had NONE. Many many power plants are now Natural Gas. March is also the month that Nuclear power plants under go refueling and are off line, which could have kept Coal plants on line during 2015 – 18, Thus those years were included to “Pad the Data.”
          If you are bored and stuck at home and not working, IEA has data on power generation and energy usage (Manufacturing) by by fuel and state by state to verify this hunch.

          • Hasn’t March 2020 been extremely “wet” in the eastern US?

            Rain, rain and more rain will strip that nitrogen oxide right out of the atmosphere.

            Nitrogen oxides are only slightly soluble in water but they form nitrous or nitric acid when they come into contact with water.

    • He, he, he.
      They always forget wood fire heating in residential areas. The number of heating furnaces has increased by hundreds of thousands the last years, together with nitrogen oxide the PM2.5 level is increasing strongly, and, of course, CO2. No heating is worse.

      • We have a weatherman here, Jörg Kachelmann who likes to shot on wood heating.
        But likes joking about the established car and truck bashing b’cause of NO2, telling from nightly truck convois turning around in residential areas far away from the usual streets they drive 😀

  4. NO2 pollution over N Italy before the shutdown (red).

    https://swprs.files.wordpress.com/2020/03/italy-smog.png?w=550&h=309

    Pretty bad in Wuhan, too.

    And Qom, Iran (notice the date of article – December 2019)

    Severe Air Pollution In Iran Turns Into Major Public Health Crisis
    https://caspiannews.com/news-detail/severe-air-pollution-in-iran-turns-into-major-public-health-crisis-2019-12-25-59/

    Prolonged NO2 causes pneumonia.

    NO2 and SO2 concentrations had a significant association with incidence of pneumonia

    Prolonged effect of air pollution on pneumonia: a nationwide cohort study
    https://erj.ersjournals.com/content/50/suppl_61/OA467

  5. Wot? No mention of CO2? Has it been removed from the pollutants list, or is it because there has been no significant reduction since the lockdown? Or maybe it’s because it’s been increasing at the same rate in spite of the lockdown?

    • Good question.

      CO2 transition into summer numbers at Mona Loa looks normal to me, though I’m no expert. Mid-May (15th or 16th) is the usual apex of each year’s seasonal CO2 growth after which the decline begins from spring greening and the Gaia’s natural consumption of Her fuel. Current daily reading: 416.33 ppm.

      If the turn-around next month happens at around 418 ppm, that to me would indicate the continuing natural increase in CO2 levels which have been visible over the span of the Keeling curve – increasing in spite of the yuge decline in ManUnkind’s industry since December in all countries.

      It’s all natural – until they adjust it **

      Scroll for the interactive maps.

      https://www.co2.earth/daily-co2

      NOTE:
      The Daily CO2 page is now a beta web app. We are making adjustments as needed to ensure that daily CO2 readings are kept up-to-date and accurate. This work is self-funded and brought to you by a small number of volunteers who are promoting widespread sharing and reporting of CO2 levels to spur conversations and innovations that ramp up efforts to stabilize GHGs in the atmospher end end the global climate crisis.

    • This addressed by Roy Spencer recently here:
      March 2020 CO2 Levels at Mauna Loa Show No Obvious Effect from Global Economic Downturn
      April 7th, 2020

      • https://wattsupwiththat.com/2020/04/08/march-2020-co2-levels-at-mauna-loa-show-no-obvious-effect-from-global-economic-downturn/#comment-2959982

        If Ed Berry is correct in this paper, human CO2 emissions play a minor part in the total increase in atmospheric CO2 and any human-caused downturn will be difficult to detect.
        Regards, Allan

        From the Abstract:
        “Human emissions through 2019 have added only 31 ppm to atmospheric CO2 while nature has added 100 ppm.”

        PREPRINT: “THE PHYSICS MODEL CARBON CYCLE FOR HUMAN CO2”
        by Edwin X Berry, Ph.D., Physics
        https://edberry.com/blog/climate/climate-physics/human-co2-has-little-effect-on-the-carbon-cycle/

        ABSTRACT
        The scientific basis for the effect of human carbon dioxide on atmospheric carbon dioxide rests upon correctly calculating the human carbon cycle. This paper uses the United Nations Intergovernmental Panel on Climate Change (IPCC) carbon-cycle data and allows IPCC’s assumption that the CO2 level in 1750 was 280 ppm. It derives a framework to calculate carbon cycles. It makes minor corrections to IPCC’s time constants for the natural carbon cycle to make IPCC’s flows consistent with its levels. It shows IPCC’s human carbon cycle contains significant, obvious errors. It uses IPCC’s time constants for natural carbon to recalculate the human carbon cycle. The human and natural time constants must be the same because nature must treat human and natural carbon the same. The results show human emissions have added a negligible one percent to the carbon in the carbon cycle while nature has added 3 percent, likely due to natural warming since the Little Ice Age. Human emissions through 2019 have added only 31 ppm to atmospheric CO2 while nature has added 100 ppm. If human emissions were stopped in 2020, then by 2100 only 8 ppm of human CO2 would remain in the atmosphere.

      • From satellite data, it is obvious that atmospheric CO2 levels and variations are dominated by natural , NOT manmade factors.

        OCO-2 satellite data
        https://ocov2.jpl.nasa.gov/galleries/videos/
        View this video (top left on the page): OCO-2 Global Visualization – Smooth (Sept 2014-Oct 2016)

        We’ve known this for decades – repeating:
        From satellite data, it is obvious that atmospheric CO2 levels and variations are dominated by natural , NOT manmade factors.
        Here is my post from 2009:
        https://wattsupwiththat.com/2009/02/24/bad-week-for-hardware-orbiting-carbon-observatory-satellite-burns-up/#comment-80606
        [excerpt]

        To all who are interested in natural CO2 cycles (there are several):

        Please examine the 15fps AIRS data animation of global CO2 at
        http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003562/carbonDioxideSequence2002_2008_at15fps.mp4

        It is difficult to see the impact of humanity in this impressive display of nature’s power.

        In the animation, does anyone see the impact of industrialization? USA? Europe? India? China? Anything related to humanity? NO.

  6. So, what we may infer, is that progress to the past, and Gaia’s Choice, normalize a Green enivronment.

  7. “significant reductions in air pollution over the major metropolitan areas of the Northeast United States. Similar reductions have been observed in other regions of the world. These recent improvements in air quality have come at a high cost, as communities grapple with widespread lockdowns”

    So the more we die from the virus the less we die from PM2.5?

  8. Perhaps the air pollution was a contributing factor for those who live with there. Lungs with minor damage, not enough to notice or warrant medical attention but enough to make a welcome mat for any coronovirus making it more prevalent in these areas.

      • Don’t be silly Steve. Elder care facilities are full of elderly people who are already on the way out and their care is usually just maintenance care.. And if you have ever spent any time there you know they are not the cleanest places.
        That has nothing to do with masses of people in polluted cities getting ill.

        • My wife would say palliative care as she is a trained age care professional here in Australia. Some facilities provide very poor services but not all. These aged people pay handsomely for their stay and care. It is a shame there are instances of poor care and cleanliness. I hope to never be put in a place like that.

  9. How big is say 5*10^15 molecules per cm^3? I would be happy with a parts per million or billion figure.
    As an aside I recall that sometime last summer here in the U.K. we all all had to clean off the dust from the Sahara from our cars. It was a pain in the neck.

  10. So air pollution follows the coast/shore line exactly and stops once it crosses over water? One graph is a 4 year average the other is just one month.

  11. Divide the map into 4 units high by 6 units wide, that’s 24 units. The blue and yellow is only about one unit more on the second map. That’s 4%, not 30%…. by extent….then a single colour change is about 25% difference, but over only about 10% of the area, so where is the 30% reduction in NO2 ?

  12. Do we know enough about air pollution anyway?
    https://advances.sciencemag.org/content/6/11/eaax8922.full

    And if I would be China, wouldn’t it be nice to have an air quality guideline which no western country can comply with? https://apps.who.int/iris/bitstream/handle/10665/69477/WHO_SDE_PHE_OEH_06.02_eng.pdf;sequence=1

    In Germany the max workplace concentration of NO2 is 950 µg/m3 and NO 2500 µg/m3. So you work 8 h in 20 times higher concentrations than outside, but they say you die from 40 µg on the street.

  13. If the reduction in NO2 emissions is primarily from a sharp reduction in consumption of transportation fuels, it suggests that efforts to reduce vehicle emissions need some review. Is this same effect seen in Los Angeles, where auto emissions drive air quality or in Houston, where industrial emissions dominate?

  14. NOx maybe a major concern among the Gang Green and the woke folk because it causes one to laugh, an embarassment to these normally maudlin, edgy, end-is-nigh folk. At least Al Gore can claim now that the “world has a fever” and recalls predicting it.

    This heretofore impossible atmospheric experiment occasioned by the global lockdown is a teaching moment that should be fully capitalized on. Unfortunately the climate troughers don’t want to find out something real and revealing about climate, human activity ’emissions’.

    There is something for everyone. Incidence of “climate diseases” such athsma? Fake news as even my doctor says? He told me at a conference he asked other physicians if they had noticed a growth in cases after all the hype and government literature, the lung association bandwagoneers, activist doctors, blah blah. They replied no they hadn’t noticed.

    Lets see about it. Lets correct the guessed carbon cycle data (I’m worried ‘vandals’ might do something to the Mauna Loa instruments). Maybe wildfires will drop with arsonists under lockdown. Maybe the hiatus in antidiluvian ship’s bucket SST measurements will move us back to the high tech ocean buoy fleet that got abandoned when it showed the oceans were cooling. Maybe we should isolate the set of satellite CO2 data that they were embarassed by, with the Congo being the ‘hottest’ CO2 patch on the globe… ozone hole change…

  15. It sure looks like we can end Climate Change by merely quarantining the entire Greater New York area permanently.

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