2021 Ozone Exceedances
(Through September 30, 2021)
Below are the exceedances of the 0.070 parts per million (ppm) eight-hour average ozone standard, and the dates they occurred for each ozone monitor in New England. These data are preliminary, not quality assured and are subject to change.
| Monitor Location | Date | Concentration (ppm) | AQI Map |
|---|---|---|---|
| Madison | August 27, 2021 | 0.084 | Peak Ozone AQI |
| Danbury | August 26, 2021 | 0.074 | Peak Ozone AQI |
| Greenwich | August 26, 2021 | 0.094 | |
| Groton | August 26, 2021 | 0.076 | |
| Madison | August 26, 2021 | 0.085 | |
| Middletown | August 26, 2021 | 0.079 | |
| Stratford | August 26, 2021 | 0.087 | |
| Westport | August 26, 2021 | 0.099 | |
| Greenwich | August 13, 2021 | 0.076 | Peak Ozone AQI |
| Groton | August 13, 2021 | 0.076 | |
| Madison | August 13, 2021 | 0.073 | |
| Stratford | August 13, 2021 | 0.080 | |
| Westport | August 13, 2021 | 0.082 | |
| Madison | August 12, 2021 | 0.078 | Peak Ozone AQI |
| Middletown | August 12, 2021 | 0.079 | |
| Stratford | August 12, 2021 | 0.073 | |
| Westport | August 12, 2021 | 0.073 | |
| Westport | August 11, 2021 | 0.071 | Peak Ozone AQI |
| Groton | August 7, 2021 | 0.075 | Peak Ozone AQI |
| Madison | August 7, 2021 | 0.083 | |
| New Haven | August 7, 2021 | 0.078 | |
| Stratford | August 7, 2021 | 0.074 | |
| Danbury | August 6, 2021 | 0.072 | Peak Ozone AQI |
| Greenwich | August 6, 2021 | 0.078 | |
| Madison | August 6, 2021 | 0.077 | |
| Middletown | August 6, 2021 | 0.071 | |
| Stratford | August 6, 2021 | 0.080 | |
| Westport | August 6, 2021 | 0.080 | |
| Greenwich | July 27, 2021 | 0.072 | Peak Ozone AQI |
| Greenwich | July 16, 2021 | 0.076 | Peak Ozone AQI |
| Middletown | July 16, 2021 | 0.076 | |
| Stratford | July 16, 2021 | 0.087 | |
| Westport | July 16, 2021 | 0.087 | |
| Greenwich | July 7, 2021 | 0.077 | Peak Ozone AQI |
| Madison | July 7, 2021 | 0.089 | |
| New Haven | July 7, 2021 | 0.081 | |
| Stratford | July 7, 2021 | 0.091 | |
| Westport | July 7, 2021 | 0.089 | |
| Middletown | July 6, 2021 | 0.077 | Peak Ozone AQI |
| Stratford | July 6, 2021 | 0.071 | |
| Westport | July 6, 2021 | 0.078 | |
| Greenwich | June 30, 2021 | 0.078 | Peak Ozone AQI |
| Madison | June 30, 2021 | 0.079 | |
| Middletown | June 30, 2021 | 0.078 | |
| New Haven | June 30, 2021 | 0.071 | |
| Stratford | June 30, 2021 | 0.080 | |
| Westport | June 30, 2021 | 0.085 | |
| Greenwich | June 29, 2021 | 0.077 | Peak Ozone AQI |
| Middletown | June 29, 2021 | 0.074 | |
| Stratford | June 29, 2021 | 0.072 | |
| Westport | June 29, 2021 | 0.080 | |
| Middletown | June 28, 2021 | 0.072 | Peak Ozone AQI |
| Groton | June 19, 2021 | 0.072 | Peak Ozone AQI |
| Madison | June 19, 2021 | 0.081 | |
| Stratford | June 19, 2021 | 0.073 | |
| Middletown | June 18, 2021 | 0.076 | Peak Ozone AQI |
| Danbury | June 7, 2021 | 0.071 | Peak Ozone AQI |
| East Hartford | June 7, 2021 | 0.074 | |
| Greenwich | June 7, 2021 | 0.072 | |
| Greenwich | June 6, 2021 | 0.082 | Peak Ozone AQI |
| Groton | June 6, 2021 | 0.074 | |
| Madison | June 6, 2021 | 0.077 | |
| Middletown | June 6, 2021 | 0.071 | |
| Stratford | June 6, 2021 | 0.078 | |
| Westport | June 6, 2021 | 0.086 | |
| Abington | June 5, 2021 | 0.082 | Peak Ozone AQI |
| Greenwich | June 5, 2021 | 0.071 | |
| Groton | June 5, 2021 | 0.079 | |
| Madison | June 5, 2021 | 0.083 | |
| Middletown | June 5, 2021 | 0.086 | |
| New Haven | June 5, 2021 | 0.076 | |
| Stratford | June 5, 2021 | 0.086 | |
| Westport | June 5, 2021 | 0.080 | |
| Danbury | May 26, 2021 | 0.075 | Peak Ozone AQI |
| Stafford | May 26, 2021 | 0.071 | |
| Cornwall | May 21, 2021 | 0.076 | Peak Ozone AQI |
| Monitor Location | Date | Concentration (ppm) | AQI Map |
|---|---|---|---|
| Cape Elizabeth | August 26, 2021 | 0.073 | Peak Ozone AQI |
| Kennebunkport | August 26, 2021 | 0.079 | |
| Bar Harbor—Cadillac Mtn. | August 7, 2021 | 0.072 | Peak Ozone AQI |
| Acadia NP—McFarland | June 7, 2021 | 0.072 | Peak Ozone AQI |
| Bar Harbor—Cadillac Mtn. | June 7, 2021 | 0.076 | |
| Cape Elizabeth | June 7, 2021 | 0.079 | |
| Kennebunkport | June 7, 2021 | 0.075 | |
| Port Clyde | June 7, 2021 | 0.072 | |
| Acadia NP—McFarland | June 6, 2021 | 0.075 | Peak Ozone AQI |
| Bar Harbor—Cadillac Mtn. | June 6, 2021 | 0.080 | |
| Cape Elizabeth | June 6, 2021 | 0.075 | |
| Kennebunkport | June 6, 2021 | 0.077 | |
| Port Clyde | June 6, 2021 | 0.076 | |
| Shapleigh Ball Park | June 6, 2021 | 0.071 |
| Monitor Location | Date | Concentration (ppm) | AQI Map |
|---|---|---|---|
| Fairhaven | August 26, 2021 | 0.084 | Peak Ozone AQI |
| Fall River | August 26, 2021 | 0.078 | |
| Truro | August 26, 2021 | 0.078 | |
| Fairhaven | June 6, 2021 | 0.071 | Peak Ozone AQI |
| Fall River | June 6, 2021 | 0.071 | |
| Truro | June 6, 2021 | 0.073 | |
| Weymouth | June 6, 2021 | 0.073 | |
| Boston—Roxbury | June 5, 2021 | 0.074 | Peak Ozone AQI |
| Brockton | June 5, 2021 | 0.071 | |
| Truro | June 5, 2021 | 0.071 | |
| Uxbridge | June 5, 2021 | 0.072 | |
| Weymouth | June 5, 2021 | 0.077 | |
| Chicopee | May 26, 2021 | 0.072 | Peak Ozone AQI |
| Monitor Location | Date | Concentration (ppm) | AQI Map |
|---|---|---|---|
| Odiorne State Park | August 26, 2021 | 0.077 | Peak Ozone AQI |
| Summit | August 16, 2021 | 0.080 | Peak Ozone AQI |
| Concord | June 6, 2021 | 0.071 | Peak Ozone AQI |
| Odiorne State Park | June 6, 2021 | 0.075 |
| Monitor Location | Date | Concentration (ppm) | AQI Map |
|---|---|---|---|
| East Providence | August 26, 2021 | 0.071 | Peak Ozone AQI |
| Narragansett | August 26, 2021 | 0.083 | |
| East Matunuck | August 13, 2021 | 0.071 | Peak Ozone AQI |
| East Providence | June 6, 2021 | 0.071 | Peak Ozone AQI |
| Narragansett | June 6, 2021 | 0.073 | |
| West Greenwich | June 6, 2021 | 0.074 | |
| East Providence | June 5, 2021 | 0.081 | Peak Ozone AQI |
| West Greenwich | June 5, 2021 | 0.082 | |
| East Matunuck | May 18, 2021 | 0.073 | Peak Ozone AQI |
| Monitor Location | Date | Concentration (ppm) | AQI Map |
|---|---|---|---|
| None |