Smog (Ground-Level Ozone)
High in the upper atmosphere, ozone protects us from deadly levels of ultraviolet radiation. But at ground level, ozone impairs breathing, causes throat irritation, chest pain, wheezing, coughing, lung inflammation and increased susceptibility to lung infection.
Ozone, also known as smog, is particularly harmful to people with existing lung or heart conditions, the elderly, the very young and people who are active outdoors. Of all air pollutants, ozone also causes the most damage to crops and other plant life. Finally, summer smog obscures our precious mountain views.
Ozone is not emitted directly into the air. It forms as a result of chemical reactions between oxygen, volatile organic compounds and nitrogen oxides in the presence of sunlight. Ozone levels are most likely to exceed federal air quality standards on very hot and still days.
Ozone can be transported long distances at night, mixing down during the day and combining with locally produced ozone. For example, prevailing winds carry ozone from Yamhill and Columbia counties toward Marion County, adding to Salem’s smog load.
Although all metropolitan areas in Oregon meet the federal health standards for ozone that were most recently revised in 1997, the EPA is considering stricter limits on ozone because the health of certain individuals is still being compromised. Several communities in Oregon may not meet this stricter standard, including the Portland, Eugene, Salem and Medford areas.
During the summer, the Oregon Department of Environmental Quality (DEQ) and Lane Regional Air Pollution Authority alert citizens when smog is predicted to exceed federal health standards. On these Clean Air Action Days, residents are encouraged to avoid activities that create more smog, such as driving. Find out how you can be a smog-buster.
