NASA data confirms pollution has nearly halved from US coal power plants
A team of scientists have used the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite to confirm major reductions in the levels of a key air pollutant generated by coal power plants in the eastern United States.
The pollutant, sulphur dioxide, contributes to the formation of acid rain and can cause serious health problems.
The scientists, led by an Environment Canada researcher, have shown that sulphur dioxide levels in the vicinity of major coal power plants have fallen by nearly half since 2005. The new findings, the first satellite observations of this type, confirm ground-based measurements of declining sulphur dioxide levels and demonstrate that scientists can potentially measure levels of harmful emissions throughout the world, even in places where ground monitoring is not extensive or does not exist.
About two-thirds of sulphur dioxide pollution in American air comes from coal power plants.
The scientists attribute the decline in sulfur dioxide to the Clean Air Interstate Rule, a rule passed by the U.S. Environmental Protection Agency in 2005 that called for deep cuts in sulphur dioxide emissions.
In response to that rule, many power plants in the United States have installed desulphurization devices and taken other steps that limit the release of sulphur dioxide. The rule put a cap on emissions, but left it up to power companies to determine how to reduce emissions and allowed companies to trade pollution credits.
While scientists have used the Ozone Monitoring Instrument to observe sulphur dioxide levels within large plumes of volcanic ash and over heavily polluted parts of China in the past, this is the first time they have observed such subtle details over the United States, a region of the world that in comparison to fast-growing parts of Asia now has relatively modest sulphur dioxide emissions.