In its bid to achieve better control over air pollution globally, NASA has been able to rely on high-resolution satellite maps of air quality proofs to monitor air pollution in 195 cities worldwide. This tracking was done for a 10-year period and its results were revealed at the American Geophysical Union summit in San Francisco.
A paper published in the Journal of Geophysical Research also contains the details of the study.
"These changes in air quality patterns aren't random," said Bryan Duncan, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "When governments step in and say we're going to build something here or we're going to regulate this pollutant, you see the impact in the data."
The team of scientists led by Duncan analyzed air pollution tracking conducted between 2005 and 2014 by the Dutch-Finnish Ozone Monitoring Instrument operative aboard NASA’s Aura satellite. The instrument was able to detect nitrogen dioxide among other atmospheric gases, and this is a chemical gas emitted by industrial plants and cars.
Nitrogen dioxide easily converts to ozone on the ground level, and it often results in respiratory irritant when it makes up smog in cities. Hotspots of the gas are common everywhere in major cities, and it could be used to evaluate the quality of air in most cases.
"With the new high-resolution data, we are now able to zoom down to study pollution changes within cities, including from some individual sources, like large power plants," said Duncan after the team evaluated trends of nitrogen dioxide levels from one year to the other globally.
With the new method for monitoring, the scientific team observed that the US and Europe are part of the top emitters of the gas, and the North China Plain in China recorded a 20% to 50% increase in nitrogen dioxide within 2005 and 2014. However, the Pearl River Delta, Beijing, and Shanghai witnessed reductions in the gas by up to 40% within this period.
Pretoria and Johannesburg in South Africa recorded the highest levels of nitrogen dioxide within the Southern Hemisphere. "We had seen seemingly contradictory trends over this area of industrial South Africa in previous studies," said Anne Thompson, co-author and chief scientist for atmospheric chemistry at Goddard. "Until we had this new space view, it was a mystery."
Don't Miss: iPhone 8: Everything You Need to Know
For the Middle East, levels of the atmospheric gas in Iran, Kuwait, and Iraq tallied with their levels of economic development since 2005, but that for Syria dropped since 2011 because of the ongoing civil war which may have disrupted industrial operations and caused the displacement of millions of people.