Trenton Air Quality in 2021
In 2021, Trenton's air quality (Trenton, NJ area) had a median daily AQI of 48 (Good) across 365 monitored days. 7 days (1.9%) reached Unhealthy for Sensitive Groups or worse, 193 were Good, and the year's peak AQI was 130 (Unhealthy for Sensitive Groups). Fine particulate matter (PM2.5) set the daily AQI on 226 of those days. The cleanest month of 2021 was January (median AQI 35, 0 days above 100) and the worst was July (median 57, 3 days above 100, peak 130).
- Good: 52.9%
- Moderate: 45.2%
- Unhealthy for Sensitive Groups: 1.9%
- Unhealthy or worse: 0.0%
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How was Trenton's air quality in 2021?
Good on a typical day: median AQI 48, with 7 days above AQI 100 out of 365 monitored — the 6th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2021: 130 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 226 days.
- ✓Cleanest month: January; worst: July.
Frequently asked questions
What was the average AQI in Trenton in 2021?▾
EPA's Air Quality System puts Trenton's (Trenton, NJ) median daily AQI for 2021 at 48, which is Good. 7 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 130.
Which month had the worst air quality in Trenton in 2021?▾
The cleanest month of 2021 was January (median AQI 35, 0 days above 100) and the worst was July (median 57, 3 days above 100, peak 130).
Was 2021 a good or bad year for Trenton's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 6th cleanest by days above AQI 100. 2021's median of 48 is above the area's typical annual median of 45.
Trenton month by month in 2021
Trenton air quality month by month, 2021 (Trenton, NJ, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| Januarycleanest | 31 | 35 | 0 | 77 | PM2.5 |
| February | 28 | 43 | 0 | 61 | PM2.5 |
| March | 31 | 42 | 0 | 74 | O3 |
| April | 30 | 42 | 0 | 84 | O3 |
| May | 31 | 45 | 1 | 122 | O3 |
| June | 30 | 53 | 1 | 101 | O3 |
| Julyworst | 31 | 57 | 3 | 130 | PM2.5 |
| August | 31 | 54 | 2 | 129 | PM2.5 |
| September | 30 | 50 | 0 | 64 | PM2.5 |
| October | 31 | 53 | 0 | 70 | PM2.5 |
| November | 30 | 52 | 0 | 78 | PM2.5 |
| December | 31 | 56 | 0 | 72 | PM2.5 |
How 2021 compares
Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 6th cleanest by days above AQI 100.
2021's median of 48 is above the area's typical annual median of 45.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Trenton
The latest EPA AirNow observation puts Trenton's AQI at 50 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Trenton air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Trenton, NJ), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.