What is baseline air quality?
The impact of gases and particles produced by human activity may be felt long distances from where the pollutants are released. Even at remote locations, typified by the ESRL/GMD observatories in Hawaii and Alaska, episodes of elevated amounts of gases such as carbon monoxide and ozone, and particles of dust and soot are periodically encountered. When long-range transport of these pollutants carries them to the continental U.S. they may compound the deterioration of air quality caused by local sources of pollution. Phenomena such as Asian dust episodes and Arctic haze are examples of the long-range transport of pollution seen at Mauna Loa, Hawaii and Barrow, Alaska.
