page_title: Smog
section_title: United States
hierarchical_section_title: Smog / Areas affected / United States
caption_attribution_description: English: US Counties Designated Non-attainment according to Environmental Protection Agency's National Ambient Air Quality Standards. Image updated 10/01/2015.
context_page_description: Smog is a type of intense air pollution. The word "smog" was coined in the early 20th century, and is a contraction of the words smoke and fog to refer to smoky fog; its opacity, and odor. The word was then intended to refer to what was sometimes known as pea soup fog, a familiar and serious problem in London from the 19th century to the mid-20th century. This kind of visible air pollution is composed of nitrogen oxides, sulphur oxides, ozone, smoke and other particulates. Man-made smog is derived from coal combustion emissions, vehicular emissions, industrial emissions, forest and agricultural fires and photochemical reactions of these emissions.
  Smog is often categorized as being either summer smog or winter smog. Summer smog is primarily associated with the photochemical formation of ozone. During the summer season when the temperatures are warmer and there is more sunlight present, photochemical smog is the dominant type of smog formation. During the winter months when the temperatures are colder, and atmospheric inversions are common, there is an increase in coal and other fossil fuel usage to heat homes and buildings.
context_section_description: Smog was brought to the attention of the general U.S. public in 1933 with the publication of the book "Stop That Smoke", by Henry Obermeyer, a New York public utility official, in which he pointed out the effect on human life and even the destruction of 3,000 acres (12 km²) of a farmer's spinach crop. Since then, the United States Environmental Protection Agency has designated over 300 U.S. counties to be non-attainment areas for one or more pollutants tracked as part of the National Ambient Air Quality Standards. These areas are largely clustered around large metropolitan areas, with the largest contiguous non-attainment zones in California and the Northeast. Various U.S. and Canadian government agencies collaborate to produce real-time air quality maps and forecasts. To combat smog conditions, localities may declare "smog alert" days, such as in the Spare the Air program in the San Francisco Bay Area.
  In the United States, smog pollution kills 24,000 Americans every year. The U.S. is among the dirtier countries in terms of smog, ranked 123 out of 195 countries measured, where 1 is cleanest and 195 is most smog polluted.
caption: Counties in the United States where one or more National Ambient Air Quality Standards are not met, as of October 2015
exif: {}