Earth-observing satellites have been discovering that air pollution is quite an inter-continental traveler. Dust from the Sahara has turned up on coral reefs in Florida, and dust from the Asian Gobi Desert has appeared as far away as the east coast of New Jersey, reports Jeannie Allen. (1) Studies on the Sierra snowpack confirmed that more than a third of the air pollution affecting California originates in China. (2) Air pollution from the northeastern United States sometimes reaches Europe, and occasionally, European pollution travels the opposite direction in return.
By the year 2020 says Harvard University’s David Parrish, imported pollution will be the primary factor degrading visibility in our national parks. The EPA estimates that 40% of the mercury that sinks out of the air and lands in the US comes from overseas. Dust from Africa’s Sahara Desert blows west across the Atlantic Ocean and helps raise particle levels above the federal health standards in Miami and other southern cities. (3) Some scientists suspect that the alarming decline in Caribbean coral reefs since the late 1970s may be due in part to other, as yet unmanned, pathogens imported in African dust. They note that the peak years of African dust deposition in the Caribbean match the years of major die-offs in the region’s reefs. (4)
Air emissions emanating from outside the US can cause states and countries to violate the Clean Air Act air quality attainment standards. What’s more, the scientific literature clearly demonstrates that in many instances, states or counties would be able to comply with attainment standards, but for emissions originating from outside the nation’s borders. (5)
Ozone provides a good example. Thirty percent of the ozone- one of the primary components of photochemical smog, found in the skies above the western United States during the spring- comes from coal-fired factories in East Asia (primarily China and India) (6). How does the EPA respond to this? By simply tightening federal ozone rules. In January of this year the EPA proposed allowing a ground-level concentration of between 60 and 70 parts per billion (ppb), down from the 75 ppb standard adopted under President George W. Bush in 2008. As Lee DeCovnick observes, “Science tells us that west coast ozone levels are increasing