NASA satellite finds 39 unreported sources of toxic air pollution
A known health hazard and contributor to acid rain, sulfur dioxide (SO2) is one of six air pollutants regulated by the U.S. Environmental Protection Agency.
Current, sulfur dioxide monitoring activities include the use of emission inventories that are derived from ground-based measurements and factors, such as fuel usage. The inventories are used to evaluate regulatory policies for air quality improvements and to anticipate future emission scenarios that may occur with economic and population growth.
But, to develop comprehensive and accurate inventories, industries, government agencies and scientists first must know the location of pollution sources.
"We now have an independent measurement of these emission sources that does not rely on what was known or thought known," said Chris McLinden, an atmospheric scientist with Environment and Climate Change Canada in Toronto and lead author of the study published this week in Nature Geosciences.
"When you look at a satellite picture of sulfur dioxide, you end up with it appearing as hotspots - bull's-eyes, in effect—which makes the estimates of emissions easier."
The 39 unreported emission sources, found in the analysis of satellite data from 2005 to 2014, are clusters of coal-burning power plants, smelters, oil and gas operations found notably in the Middle East, but also in Mexico and parts of Russia. In addition, reported emissions from known sources in these regions were—in some cases—two to three times lower than satellite-based estimates.
Altogether, the unreported and underreported sources account for about 12 percent of all human-made emissions of sulfur dioxide - a discrepancy that can have a large impact on regional air quality, said McLinden. ■