With the help of a satellite-based method, a group of scientists from Environment and Climate Change Canada, and two universities have recently identified 39 unreported sources of air pollution caused by toxic sulfur dioxide emissions.
Sulfur dioxide (SO2) is known as a major contributor to acid rain and one of six air pollutants under regulations by the U.S. Environmental Protection Agency. Emission inventories are used to monitor sulfur dioxide activities. These inventories come from ground-based factors and measurements, including fuel usage.
Plus, their purpose is to anticipate emission situations that may occur with population and economic growth as well as to evaluate regulations for improvement in air quality. However, scientists, government agencies, and industries need to know the location of pollution sources to develop accurate and comprehensive inventories.
According to Chris McLinden, lead author of the study and atmospheric scientist with Environment and Climate Change Canada in Toronto, thanks to this new independent measurement method, sulfur dioxide emissions appear as hotspots in satellite picture, making them easier to identify.
The data from 2005 to 2014 revealed that there were 39 unreported emission sources from oil and gas operations in the Middle East, Russia, Mexico, smelters and clusters of coal-burning power plants. Plus, some of the reported emissions from known sources in those regions were up to three times lower than what the satellite estimated.
Furthermore, the total underreported and unreported sources consist of around 12 percent of all human-made sulfur dioxide emissions, which might critically endanger the regional air quality.
Thanks to the collaboration of Nova Scotia, Dalhousie University in Halifax, College Park and the University of Maryland, 75 natural sources of sulfur dioxide from non-erupting volcanoes were identified and reported as leaking toxic gas. It is another benefit of this method because many volcanoes are not monitored due to their remote location.
According to Nickolay Krotkov, co-author, and atmospheric scientist, this process was possible only thanks to two important steps. The first consisted in a computer processing improvement that transformed raw satellite observations into accurate estimates of sulfur dioxide concentrations.
Even smaller levels of sulfur dioxide will be easily identified from now on, such as those emitted by medium-size power plants and oil-related activities. Hopefully, this new technology will help reduce the level of air pollution, making the world a safer and healthier place.