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Region 1: EPA New England

Ground-level Ozone (Smog) Information

Ground-level ozone presents a serious air quality problem in New England. In 2008, EPA revised the ozone standard to a level of 0.075 parts per million, 8-hour average. Over the last 5 years (2007 through 2011), there have been an average of 28 days per summer when New England's air exceeded this standard.

Ground-level ozone is formed by a chemical reaction between VOCs and oxides of nitrogen (NOx) in the presence of sunlight. Ozone concentrations can reach unhealthful levels when the weather is hot and sunny with little or no wind. View ozone concentrations and corresponding weather conditions for a day in 1998 when high ozone concentrations were measured across Southern New England. In New England, high ozone levels usually occur between 1:00 and 7:00 pm from May through September.

Visit EPA-New England's Air Quality Index page to get real-time and forecasted air pollution data in an understandable visual format. This information is provided so the public can take action to protect their health, and reduce pollution.

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The Ozone Problem
High concentrations of ozone near ground level can be harmful to people, animals, crops... more


Daily Air Quality Index
Real-time ozone movies and forecast maps are available in an understandable visual format... more

Air Quality Guide (PDF) (2 pp, 31K, about PDF)
This guide provides information about ways to protect your health when ozone levels reach the unhealthy range... more (PDF) (2 pp, 31K, about PDF)
  Map of Ozone Nonattainment Areas in New England
The maps show the areas in New England that are presently designated "nonattainment"... more
Ozone and Your Health
Ozone, the main ingredient of smog, presents a serious air quality problem in many parts of the United States... more
  Historical Exceedances of the Ground-level Ozone Standards
View tables and graphs of the number of 8-hour exceedance days for areas in New England... more
Information on Revised Ozone Standard and Revised Particulate Matter Standard
These pages provide access to plain English fact sheets and the complete text of the rules... more
  Ozone Control Strategies
View information on the strategies developed and implemented in New England to prevent elevated concentrations of ozone smog ... more
Sources Contributing to Ozone Formation
Ozone smog is formed when volatile organic compounds (VOCs), and nitrogen oxides (NOx) interact in ... more


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