NASA Scientists finds 39 unreported human-made sources of toxic sulfur dioxide emissions

NASA scientists located 39 unreported and major human-made sources of toxic sulfur dioxide emissions. They used a new satellite-based method to locate the sources of toxic emissions.

The study was published in The Nature Geoscience journal on 30 May 2016.

NASA scientists of Environment and Climate Change, Canada along with The University of Maryland, College Park, and Dalhousie University in Halifax, Nova Scotia, contributed to the study.

Highlights of the Study

• The 39 unreported emission sources were found after analyzing data of satellite from 2005 to 2014.

• They 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.

• Along with this the reported emissions from known sources in these regions were in some cases two to three times lower than satellite-based estimates.

• The unreported and underreported sources account for about 12 percent of all human-made emissions of sulfur dioxide.

• The research team also located 75 natural sources of sulfur dioxide like non-erupting volcanoes slowly leaking the toxic gas throughout the year.

• Smaller SO2 concentrations were also detected from those emitted by human-made sources such as oil-related activities and medium-size power plants.

Significance of the findings

A new computer program was used by the research team to more precisely detect SO2 that had been dispersed and diluted by winds.

It was the first improvement in the computer processing that transforms raw satellite observations from the Dutch-Finnish Ozone Monitoring Instrument aboard NASA's Aura spacecraft into precise estimates of sulfur dioxide concentrations.

While not necessarily unknown, many volcanoes are in remote locations and not monitored, so this satellite-based data set is the first to provide regular annual information on these passive volcanic emissions.

It takes the estimation of SO2 emission beyond the present use of emission inventories derived from ground-based measurements and factors such as fuel usage. In fact, the study uses more accurate estimates of wind strength and direction derived from a satellite data-driven model to trace the pollutant back to the location of the source. It also helped to estimate the quantity of SO2 that was emitted from the smoke stack.

About Sulfur dioxide (SO2)

Sulfur dioxide (SO2) is one of six air pollutants that are regulated by the US Environmental Protection Agency. It is hazardous to health and contributes a lot to acid rain.