2025 PM2.5 Exceedances
(Through August 5, 2025)
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.
On this page:
Connecticut
| Monitor Location | Concentration (µg/m3) | Date/AQI Map |
|---|---|---|
| Cornwall | 41.8 | August 5, 2025 PM 2.5 AQI Map |
| Danbury | 39.7 | |
| East Hartford | 45.9 | |
| Hartford | 43.1 | |
| Waterbury | 38.2 | |
| Cornwall | 37.8 | August 4, 2025 PM 2.5 AQI Map |
| Cornwall | 49 | July 26, 2025 PM 2.5 AQI Map |
| Danbury | 42.5 | |
| East Hartford | 39.9 | |
| Hartford | 38.1 | |
| Waterbury | 39.9 |
Maine
| Monitor Location | Concentration (µg/m3) | Date/AQI Map |
|---|---|---|
| Portland Tukey | 36.7 | August 4, 2025 PM 2.5 AQI Map |
| Rumford | 38 | |
| Presque Isle DEP | 42.2 | August 3, 2025 PM 2.5 AQI Map |
| Madawaska PSB | 40.9 | |
| Presque Isle Riverside | 40.4 | |
| Rumford | 35.5 | July 27, 2025 PM 2.5 AQI Map |
| Portland Tukey | 40.8 | July 26, 2025 PM 2.5 AQI Map |
| Rumford | 49.3 | |
| Madawaska | 35.7 | July 15, 2025 PM 2.5 AQI Map |
| Portland Tukey | 35.5 | June 8, 2025 PM 2.5 AQI Map |
| Madawaska | 45.4 | June 7, 2025 PM 2.5 AQI Map |
| Presque Isle DEP | 44.2 | |
| Presque Isle Riverside | 39.2 | |
| Madawaska | 47.6 | June 6, 2025 PM 2.5 AQI Map |
| Mi'kmaq Nation | 37.3 | |
| Presque Isle DEP | 47.8 | |
| Presque Isle Riverside | 45.2 |
Massachusetts
| Monitor Location | Concentration (µg/m3) | Date/AQI Map |
|---|---|---|
| Chicopee | 39 | August 5, 2025 PM 2.5 AQI Map |
| Greenfield | 40 | |
| North Adams | 43 | |
| Pittsfield ES | 44.7 | |
| Springfield | 45 | |
| Ware | 39 | |
| North Adams | 35.9 | August 4, 2025 PM 2.5 AQI Map |
| Pittsfield ES | 36.3 | |
| Boston-Von Hillern | 37.5 | July 26, 2025 PM 2.5 AQI Map |
| Chicopee | 39.2 | |
| Greenfield | 40.8 | |
| North Adams | 42.4 | |
| Pittsfield ES | 42.5 | |
| Springfield | 44.1 | |
| Ware | 41.9 | |
| Boston-Von Hillern | 35.9 | June 8, 2025 PM 2.5 AQI Map |
New Hampshire
| Monitor Location | Concentration (µg/m3) | Date/AQI Map |
|---|---|---|
| Keene | 38.6 | August 5, 2025 PM 2.5 AQI Map |
| Lebanon | 40.5 | |
| Miller State Park | 37 | |
| Lebanon | 35.5 | August 4, 2025 PM 2.5 AQI Map |
| Miller State Park | 36.3 | |
| Keene | 41.3 | July 26, 2025 PM 2.5 AQI Map |
| Lebanon | 40.1 | |
| Miller State Park | 44.4 |
Rhode Island
| Monitor Location | Concentration (µg/m3) | Date/AQI Map |
|---|---|---|
Vermont
| Monitor Location | Concentration (µg/m3) | Date/AQI Map |
|---|---|---|
| Bennington | 38.8 | August 5, 2025 PM 2.5 AQI Map |
| Underhill | 46.8 | August 4, 2025 PM 2.5 AQI Map |
| Bennington | 43.9 | July 26, 2025 PM 2.5 AQI Map |
| Rutland | 47.2 | |
| Underhill | 63.3 | |
| Underhill | 37.5 | June 7, 2025 PM 2.5 AQI Map |