New England Experienced an Increase in the Number of Unhealthy Air Quality Days During the 2021 Ozone Season

October 19, 2021

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BOSTON (Oct. 19, 2021) — Today the U.S. Environmental Protection Agency's (EPA) New England region released data that demonstrated New Englanders experienced more unhealthy air quality days in 2021 compared to 2020. Based on data collected between March and September 2021, there were 23 days when ozone concentrations in New England reached unhealthy levels. By contrast, in 2020 there were 18 unhealthy ozone days in New England.

The number of unhealthy ozone days recorded in each state this summer is as follows:

  • 21 days in Connecticut (compared to 17 days in 2020)
  • 4 days in Maine (compared to 1 day in 2020)
  • 4 days in Massachusetts (compared to 3 days in 2020)
  • 3 days in New Hampshire (compared to 0 days in 2020)
  • 5 days in Rhode Island (compared to 4 days in 2020)
  • 0 days in Vermont (compared to 0 days in 2020).

"We can all feel proud of the progress New England has made in reducing ozone pollution over the past several decades," said EPA New England Acting Regional Administrator Deborah Szaro. "Unfortunately, our region, and particularly coastal Connecticut, continues to experience an unacceptable number of days with unhealthy air quality. By continuing to implement rules to reduce air pollution from cars, trucks, and power plants, EPA is taking action to improve air quality for all New Englanders."

For New England, the summer of 2021 brought a record-setting wet July bookended by a warm and sunny June and August. This is reflected in the number of unhealthy days recorded across five of the six New England states during June and August. Since 1983, New England has experienced a decrease in the number of unhealthy ozone days. In 1983, New England had 118 unhealthy days, compared with only 23 this year. The downward trend is attributed to an overall reduction in the emissions that form ozone.

In 2014, EPA finalized stringent standards for new cars sold after 2017. The automobile and gasoline rule, known as Tier 3, works to help lower automobile pollution significantly. The Tier 3 emissions standards for cars represent an additional 80% reduction of ozone-causing pollution when compared to the average in 2014. In addition, EPA issued an update to the Cross-State Air Pollution Rule (CSAPR), which went into effect on June 29, 2021. This rule reduces summertime NOX emissions from power plants in 12 states located in the eastern region of the United States.

More information:

To view EPA's daily air quality forecast and to sign up for air quality alerts via email, whenever high concentrations of ground-level ozone or particle pollution is expected in your area, visit:

To view the record of unhealthy air days for this summer, by date and monitor location, visit:

For data on the recorded unhealthy air days for each New England state from 1983 through 2021 visit:

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