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EPA Region 1
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2021 PM2.5 Exceedances

(Through September 30, 2021)

Below are the exceedances of the 35 µg/m3 24-hour average PM2.5 standard and the dates they occurred for each continuous PM2.5 monitor in New England. Data from these monitors are not used for official purposes such as determining if an area meets the PM2.5 standard. All data are preliminary and subject to change.

  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Connecticut
Monitor Location Date Concentration
(µg/m3)
AQI Map
Groton July 27, 2021 37.5 PM 2.5 AQI
New Haven July 27, 2021 40
Waterbury July 27, 2021 38.3
Bridgeport July 26, 2021 35.8 PM 2.5 AQI
Cornwall July 26, 2021 52.2
Danbury July 26, 2021 36.4
East Hartford July 26, 2021 49.8
Hartford July 26, 2021 49.6
New Haven July 26, 2021 37
Waterbury July 26, 2021 50.9
Bridgeport July 20, 2021 40.8 PM 2.5 AQI
Cornwall July 20, 2021 50.3
Danbury July 20, 2021 49.5
East Hartford July 20, 2021 42
Hartford July 20, 2021 43.9
New Haven July 20, 2021 37.7
Waterbury July 20, 2021 52.6
Maine
Monitor Location Date Concentration
(µg/m3)
AQI Map
Rumford July 26, 2021 40.2 PM 2.5 AQI
Massachusetts
Monitor Location Date Concentration
(µg/m3)
AQI Map
Boston–Kenmore July 26, 2021 53.4 PM 2.5 AQI
Boston–Roxbury July 26, 2021 41.1
Boston–Von Hillern July 26, 2021 44.1
Chelmsford July 26, 2021 59
Chelsea July 26, 2021 61.6
Chicopee July 26, 2021 41.4
Haverhill July 26, 2021 40.5
Lynn July 26, 2021 44.3
Springfield July 26, 2021 36.9
Weymouth July 26, 2021 50
Worcester July 26, 2021 45.2
Chelmsford July 20, 2021 35.7 PM 2.5 AQI 
Chelsea July 20, 2021 35.5
Pittsfield July 20, 2021 39.4
Worcester July 20, 2021 36.5
New Hampshire
Monitor Location Date Concentration
(µg/m3)
AQI Map
Keene July 26, 2021 45.9 PM 2.5 AQI
Laconia July 26, 2021 39.2
Lebanon July 26, 2021 37.5
Londonderry July 26, 2021 54.1
Miller State Park July 26, 2021 53
Portsmouth July 26, 2021 37.7
Londonderry July 20, 2021 35.9 PM 2.5 AQI 
Miller State Park July 20, 2021 37.4
Rhode Island
Monitor Location Date Concentration
(µg/m3)
AQI Map
CCRI Providence July 26, 2021 40.8 PM 2.5 AQI
East Providence July 26, 2021 42.5
Near Road July 26, 2021 41.4
West Greenwich July 26, 2021 42.3
Vermont
Monitor Location Date Concentration
(µg/m3)
AQI Map
Bennington July 26, 2021 41.2 PM 2.5 AQI
Burlington July 26, 2021 47
Rutland July 26, 2021 40.8
Underhill July 26, 2021 46.2

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Last updated on April 19, 2022