The USA may be producing less air pollution, according to data, but smog levels are still rising on the country’s west coast. Researchers are pointing to pollutants in Asian countries as the culprit, as these toxic materials drift over the Pacific Ocean.
According to Rob Schmitz of NPR, “Scientists found Asian air pollution contributed as much as 65 percent of an increase in Western ozone in recent years. China and India, where many consumer products are manufactured, are the worst offenders.” Scientists from the National Oceanic and Atmospheric Administration and the Environmental Protection Agency led the research.
The problem lies in the presence of nitrogen oxides, which Asian countries emit. These break down in sunlight in reactions that produce ozone – a process that has tripled since 1990. When these dangerous gases reach North America, they offset any improvements in US air quality that have been made by cutting down on nitrogen oxide emissions.
China continues to do the same, cutting down on its own nitrogen oxide emissions to address the severe air pollution problem it has, but researchers say that “rising global methane and NOx emissions in the tropical countries (e.g., India) in Asia, where O3 [ozone] production is more efficient, may become more important in the coming decades.”
This means that there is a need for a global approach when it comes to improving air quality, the study says.
A global perspective is necessary when designing a strategy to meet US O3 air quality objectives.
The study observed levels of ozone at ground level from 1980 to 2014, as ozone is the primary component in smog. The researchers, led by Meiyun Lin of NOAA, also gathered data on pollution levels across the United States.
Information collected ranged from Joshua Tree National Park in Southern California to the eastern part of the country, and showed that the spike in man-made emissions in Asia “is the major driver” of rising ozone levels in the USA.
The EPA states that ozone “can be harmful to people, animals, crops, and other materials” and that it “can aggravate asthma, and can inflame and damage cells that line your lungs.”
The study was published in Atmospheric Chemistry and Physics.