Results of 25 year study, 1980-2014, published Wed. 3/1/17 in journal Atmospheric Chemistry and Physics.
3/2/17, "Air pollution in Asia is wafting into the USA, increasing smog in West," USA Today, Doyle Rice
"Air pollution from China, India and several other Asian countries has
wafted across the Pacific Ocean over the past 25 years,
increasing levels of smog in the western U.S., a study finds.
also known as ground-level ozone, is harmful to human health, because
it can exacerbate asthma attacks and cause difficulty breathing. It also
harms sensitive trees and crops. It's different than the "good" ozone
up in the stratosphere, which protects life on Earth from the sun's
harmful ultraviolet rays.
Scientists measured ozone levels
recorded at springtime for the past 25 years in 16 national parks in the
western U.S., including Yellowstone, Yosemite and Grand Canyon. The
parks' locations farther away from cities, where smog is typically
expected, made them ideal spots for the study.
The team looked at levels in the spring when wind and weather patterns push Asian pollution across the Pacific Ocean, said Meiyun Lin,
a scientist at the National Oceanic and Atmospheric Administration who
led the study. In the summer, when those weather patterns subside, ozone
levels in the national parks remained well above normal.
air pollution was, by far, the biggest contributor to smog in the West,
the researchers found. The team also looked at other factors, such as
wildfires and methane from livestock. Asian air pollution contributed as
much as 65% of the western U.S. ozone increase, while wildfire
emissions supplied less than 10% and methane about 15%.
1992, Asia has tripled its emissions of smog-forming chemicals such as
nitrogen oxides. Though China and India are the worst offenders, North
and South Korea and Japan also contribute, said Lin, who is also a
research scholar at Princeton University.
The smog levels in the
western U.S. have increased each year despite a 50% reduction in U.S.
emissions of smog-forming pollutants.
"Twenty years ago,
scientists first speculated that rising Asian emissions would one day offset some of the United States' domestic ozone reductions," said Owen
Cooper, a senior research scientist at the University of Colorado and
NOAA, who was not directly involved in the study. Now that prediction has come true, he said.
Asian pollution only slightly contributes
to smog in the eastern U.S., the study found. Levels there typically
spike during intense summer heat waves.
The study was published Wednesday in the journal Atmospheric Chemistry and Physics."
Link to journal article:
surface ozone trends and extremes from 1980 to 2014: quantifying the
roles of rising Asian emissions, domestic controls, wildfires, and
climate," Atmospheric Chemistry and Physics,
weak or insignificant observed O3 trends at WUS (Western US) rural sites."...
Friday, April 7, 2017
US reduced smog emissions by 50% but US efforts nullified by Asia pollutants carried by winds across Pacific, 25 year published study finds. Excess ozone in US national parks comes from Asia, 1980-2014 study-USA Today, 3/2/17, study published 3/1/17
Posted by susan at 4:35 AM