Asian ozone pollutes Hawaii and USA west coast – varies with climatic shifts

Asian ozone pollution in Hawaii is tied to climate variability (Nature Geoscience)

Asian air pollution
Asian pollution drifts east toward North America in 2010. Hawaii is denoted by the star. (Source: Nature Geoscience)

By Joanne Curcio, Program in Atmospheric and Oceanic Sciences

Air pollution from Asia has been rising for several decades but Hawaii had seemed to escape the ozone pollution that drifts east with the springtime winds. Now a team of researchers has found that shifts in atmospheric circulation explain the trends in Hawaiian ozone pollution. 

Ozone levels during autumn 1975-2012

Researchers found that ozone levels measured during autumn at Mauna Loa Observatory in Hawaii (black line) accurately reflect the trend in rising Asian air pollution from 1975 to 2012. The researchers demonstrated that the autumnal rise in ozone could be explained by atmospheric and climatic shifts over periods of decades. Using a chemistry-climate model, the researchers modeled this autumnal variation in ozone using constant (red) and time-varying (purple) emissions of ozone precursors. (Source: Nature Geoscience.)

The researchers found that since the mid-1990s, these shifts in atmospheric circulation have caused Asian ozone pollution reaching Hawaii to be relatively low in spring but rise significantly in autumn. The study, led by Meiyun Lin, an associate research scholar in the Program in Atmospheric and Oceanic Sciences (NOAA) at Princeton University and a scientist at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory, was published in Nature Geoscience.

“The findings indicate that decade-long variability in climate must be taken into account when attributing U.S. surface ozone trends to rising Asian emissions,” Lin said. She conducted the research with Larry Horowitz and Songmiao Fan of GFDL, Samuel Oltmans of the University of Colorado and the NOAA Earth System Research Laboratory in Boulder; and Arlene Fiore of the Lamont-Doherty Earth Observatory at Columbia University.

Although protective at high altitudes, ozone near the Earth’s surface is a greenhouse gas and a health-damaging air pollutant. The longest record of ozone measurements in the U.S. dates back to 1974 in Hawaii. Over the past few decades, emissions of ozone precursors in Asia has tripled, yet the 40-year Hawaiian record revealed little change in ozone levels during spring, but a surprising rise in autumn.

Through their research, Lin and her colleagues solved the puzzle. “We found that changing wind patterns ‘hide’ the increase in Asian pollution reaching Hawaii in the spring, but amplify the change in the autumn,” Lin said.

Using chemistry-climate models and observations, Lin and her colleagues uncovered the different mechanisms driving spring versus autumn changes in atmospheric circulation patterns. The findings indicate that the flow of ozone-rich air from Eurasia towards Hawaii during spring weakened in the 2000s as a result of La-Niña-like decadal cooling in the equatorial Pacific Ocean. The stronger transport of Asian pollution to Hawaii during autumn since the mid-1990s corresponds to a positive pattern of atmospheric circulation variability known as the Pacific-North American pattern.

“This study not only solves the mystery of Hawaiian ozone changes since 1974, but it also has broad implications for interpreting trends in surface ozone levels globally,” Lin said. “Characterizing shifts in atmospheric circulation is of paramount importance for understanding the response of surface ozone levels to a changing climate and evolving global emissions of ozone precursors,” she said.

The work was supported by NOAA’s Cooperative Institute for Climate Science at Princeton University. Ozone measurements were obtained at Mauna Loa Observatory, operated by NOAA’s Earth System Research Laboratory.


Read the abstract

Meiyun Lin, Larry W. Horowitz, Samuel J. Oltmans, Arlene M. Fiore, Songmiao Fan. Tropospheric ozone trends at Mauna Loa Observatory tied to decadal climate variability. Nature Geoscience, Published Online: 26 January, 2014,

Source: Princeton Journal Watch

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January 27, 2014 6:32 pm

Where are CO2 measured?

January 27, 2014 6:34 pm

I would like to see the same group using the same methodology model the CO2 coming from Asia that is being measured at Mauna Loa.

January 27, 2014 6:37 pm

Asia is doing its part to block the Ozone hole.
So how come the ozone from Asia has tapered right off to a narrow red point by the time it reaches the US coast, and then suddenly when it reaches California it forms a large red blob? How do we know this red blob is Asia Ozone and not California Ozone?

January 27, 2014 6:42 pm

And what it that orange blob down by Northern Florida? Seems strange that Asian Ozone would stick there, as if Florida was some sort of Ozone magnet. How do we know there isn’t US Ozone being produced just North of Florida?
All and all it looks like the US is way behind China in filling in the Ozone Hole and there is a real risk of an Ozone Gap forming.

January 27, 2014 6:43 pm

Why isn’t the growth of particulates from Asia a Cause of the Pause?
If it is, then why isn’t our own air pollution increase in the 1960s-70s a cause of the global cooling scare? And why wouldn’t our clean up of pollution in the 80s and 90s be the primary cause of the measured warming?
Someone must have run the numbers.
Where is the evidence that the Global Warming that has so many in a panic is caused by growth of green house gasses and not the imposition of the Clean Air Act in the 80s and 90s?
Anyone have links to the studies?

January 27, 2014 6:47 pm

Researchers found that ozone levels measured during autumn at Mauna Loa Observatory in Hawaii (black line) accurately reflect the trend in rising Asian air pollution from 1975 to 2012.
So how do we know that CO2 levels in Mauna Loa are not caused by rising Asian air pollution from 1975 to 2012? After all, the Chinese are burning a lot of coal manufacturing all those goods that used to be made in the US. How do we know that the CO2 isn’t blowing back to the US along with the Ozone? That would explain why CO2 at Mauna Loa is seasonal, just like the Ozone.

Don Bennett
January 27, 2014 7:40 pm

I drove up to the MLO today on a reccon trip before a hike later in the week. Windy as all get out up there today in one of the more desolate areas around. A’a lava fields for miles and miles. Not my idea of a cheery place to work, however, the view of Mauna Kea is stunning. The fume from Kilauea was coming up over the northeast shoulder of the mountain today with the wind generally out of the south.

January 27, 2014 8:00 pm

“The findings indicate that decade-long variability in climate must be taken into account when attributing U.S. surface ozone trends to rising Asian emissions,”
So depending on depending on the vagaries of Rossby waves there can be more or less of the television sets, computers, and cell phones “recycled” here and burned in bonfires in the barrios over there, wafting over Hawaii in the westerlies? No shoot, Sherlock.

Crispin in Waterloo
January 27, 2014 8:08 pm

Let’s see some numbers on this ‘health harming’ ozone drifting to Hawaii. What is the natural ozone level (in ppm) average for the whole atmosphere? What is man’s % contribution to this?
We need a little perspective to save us from text like:
AG CO2 warming is a given.
Ozone being a health hazard thousands of km away is a given.
Ozone is largely caused by human activity, is a given.
AG Ozone warming is a given.
The ozone hole is ALSO cause by human activity. (OMG!)
It is worse than we thought, is a given.
We are all going to die, is a given.
I agree that we are all going to die. Eventually.

Robert Westfall
January 27, 2014 8:19 pm

“Using a chemistry-climate model”
How do we know that this modeling is any more honest that the climate models. The problem with climate “science” is the trust is gone.

January 27, 2014 8:35 pm

I like Asian Ozone. Has a sweet and sour taste. AND, once you’ve breathed some…3 days later, you want to breath some more. (Sorry, I’ll leave now…)

January 27, 2014 9:12 pm

ferdberple says:
January 27, 2014 at 6:42 pm
And what it that orange blob down by Northern Florida? Seems strange that Asian Ozone would stick there, as if Florida was some sort of Ozone magnet. How do we know there isn’t US Ozone being produced just North of Florida?

“That blob” of ozone north of Florida?
It’s “natural” … Comes from 10 quadrillion pine trees all emitting “:natural ozone” from every square yard, round yard, rectangular yard, backyard, front yard, and brush yard between the Gulf Coast and the Carolina’s east coast. If you don’t mow your yard every two weeks, it grows pine trees. If you do mow your yard every two weeks, it grows pine trees. If you cut all the trees down in a vacant lot, it will grow waist-high pine trees in one year.
but, you see, the EPA wrote its ozone laws for a “national audience” (based on readings in Los Angeles’ entrapped basin of smog-polluted air) so “we” in the Atlanta GA area have to pay more to get “special” ozone-preventing gasoline refined every summer.
So the trees can add even more ozone to the air because they are growing faster due to the extra CO2 in the air.

Brian R
January 27, 2014 9:25 pm

Seems that China’s smog producing machines are working year round. So why are they only looking at autumn?

Poems of Our Climate
January 27, 2014 9:36 pm

Ferd. It looks to be sucking directly into the opening called the San Francisco Bay by the Golden Gate where there is a great vacuum to the Central Valley, Sacramento it looks like. The blob is a flat area; to the north and south of the Bay Area/San Francisco are blocking coastal mountains.
There is almost no pollution in San Fran from this suction. The Valley gets all the smog as per the graphic.

January 27, 2014 10:00 pm

Poems of Our Climate says:
January 27, 2014 at 9:36 pm
It looks to be sucking directly into the opening called the San Francisco Bay
Clearly the ozone is leaking out of California at SF bay. From there it is carried across the Pacific by inertia and the rotation of the earth, where it backs up against the Himalayas, creating a huge air pollution problem in China.

Poems of Our Climate
January 27, 2014 10:26 pm
Poems of Our Climate
January 27, 2014 10:34 pm

Ferd, I’m responding to your statement about the odd pattern going into California. This also might help:

January 27, 2014 10:42 pm

Maybe there’ll be some more red states for the next election.

January 28, 2014 5:38 am

If Hawaii is downwind of China’s ozone production, wouldn’t it also be downwind of China’s CO2 production? China’s historical coal production/consumption roughly tracks the Keeling curve, which is based on CO2 data gathered in Hawaii.

Brian H
January 28, 2014 11:48 am

Many of the comments above ignore (= don’t understand) the difference between stratospheric and surface ozone. Surface ozone has nothing to do with the Ozone Hole.
Learn to read before spouting nonsense. It will help your reputations.

January 28, 2014 12:57 pm

At least I got some great deals at Costco and Target.

January 28, 2014 1:22 pm

Ozone is not a pollutant.
Some points from:
“When the oxygen (O2) that is all around us rises to the upper atmosphere, and is exposed to the sun’s ultraviolet rays, that oxygen is naturally turned into ozone (O3).
That is the “ozone layer” that protects us from the sun’s harmful UV rays.
Since ozone is heavier than air, it falls back to earth. This is the ozone that naturally purifies our air and water.
Because it is made up entirely of oxygen, ozone is sometimes called “activated oxygen”.
Ozone is NOT smog or pollution as sometimes mistakenly reported.
Ozone also occurs commonly in nature as a result of lightning strikes during thunderstorms.
The “fresh, clean, spring rain ” smell that we notice after a storm results from natures creation of ozone.
Ozone is also created by water falls.
Ozone cannot be stored or transported because of its unstable tendency to break down quickly, so ozone must be generated on site.
Because gaseous ozone is highly reactive, it readily oxidizes (breaks down) organic matter. When the ozone encounters another compound, one oxygen atom will break away, attach itself to the compound, and oxidize it. Ozone actually breaks down odor-causing compounds, thereby eliminating the odor and changing the ozone back to oxygen (O2).”
“ozone noun \ˈō-ˌzōn\ : a form of oxygen that is found in a layer high in the earth’s atmosphere
: fresh healthy air especially near the sea”
Mauna Loa claims to be “a pristine site uncontaminated by local production and measuring the well mixed unpolluted background via trade winds”, in reality it is sitting on one the the world’s most active volcanic sites producing loads of carbon dioxide and, as here admitted, is in this wind stream from China, it is already measuring China’s CO2..

Mike Tremblay
January 28, 2014 10:48 pm

When I first read the headline for this post, ‘Asian ozone pollutes Hawaii and USA west coast …’, I almost spit my coffee all over my screen. My first reaction was ‘How could any competent chemist allow such nonsense to be published?’ Ozone has such a short half-life that any produced in Asia wouldn’t even get past the Yellow Sea, let alone cross the entire North Pacific.
Then I read the abstract – nowhere are they claiming ozone is crossing the Pacific, it is all about ozone precursors – the chemicals which contribute to the formation of terrestrial ozone.
Not being able to read the entire study I can’t honestly give any appraisal of the validity of their findings. I will say that they should have examined the local contribution from anthropogenic and natural sources in the Hawaiian Islands before they concluded that the ozone precursors come from Asia. Most of these precursors present in Hawaii likely come from local automobiles and industry as well as from the local volcanic emissions.
Another item is the presence of ozone – terrestrial ozone is produced in the lower atmosphere by high energy discharges in the presence of oxygen, typically arcing, sparking, static discharges, and lightning – you can smell it after a lightning storm or even when you remove your clothes from a drier (because of the static discharges). An increase of local ozone concentrations could just as easily be the result of natural variations in thunderstorms – was this examined?
Further information on ozone. We can smell it at concentrations of 0.02 – 0.05 ppm. It is poisonous at low concentrations with an LC50 (Lethal Concentration 50% – half of the test population dies) of 12.6 ppm for 3 hrs (mice) and 35.5 ppm (hamsters) for 3 hrs. It is considered a pollutant at terrestrial levels because of its effects on living tissue and organic matter – a quality which makes it a very effective disinfectant, especially for use in water treatment. You can read the MSDS sheet ( to learn more.

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