Trenton Air Quality in September
Across 2019–2025, Trenton's September air quality had a median AQI of 44 (Good) over 210 monitored days in the Trenton, NJ area. 0.0% of September days (0 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 53.3% of days. The cleanest September on record here was 2020 (median AQI 34, 0 days above 100) and the worst was 2021 (median 50, 0 days above 100, peak AQI 64).
- Good: 69.0%
- Moderate: 31.0%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Extra Protection for Trenton Homes
Air quality in Trenton is moderate (AQI 52), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
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How is the air in Trenton in September?
Good on a typical day: median AQI 44 across 2019–2025, with 0.0% of September days above AQI 100. Ground-level ozone is the main driver.
- ✓69.0% of September days were Good (AQI 0–50), 31.0% Moderate (51–100).
- ✓0 days of 210 reached AQI 101+; the September peak was 93.
- ✓Best September: 2020; worst September: 2021.
Frequently asked questions
What is the air quality like in Trenton in September?▾
Across 2019–2025, the median daily AQI in Trenton in September was 44 (Good). 69.0% of days were Good, 31.0% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is September a good time for outdoor exercise in Trenton?▾
A typical September day in Trenton sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of September days reached AQI 101+ in 2019–2025.
Which pollutant causes Trenton's September air quality problems?▾
Ground-level ozone set the daily AQI on 53.3% of September days in Trenton. The highest September AQI recorded in 2019–2025 was 93 (Moderate), in 2021.
Trenton September air quality, year by year
Trenton September air quality by year (Trenton, NJ, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 48 | 0 | 90 | O3 |
| 2020cleanest | 30 | 34 | 0 | 58 | O3 |
| 2021worst | 30 | 50 | 0 | 64 | PM2.5 |
| 2022 | 30 | 40 | 0 | 68 | O3 |
| 2023 | 30 | 42 | 0 | 93 | PM2.5 |
| 2024 | 30 | 43 | 0 | 90 | O3 |
| 2025 | 30 | 45 | 0 | 61 | O3 |
What September air means in Trenton
A typical September day in Trenton sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of September days reached AQI 101+ in 2019–2025.
September's median AQI of 44 is in line with Trenton's whole-year median of 45, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median September AQI across every EPA metro area (100,699 metro-days, 2019–2025) is 43, so Trenton runs in line with the national September norm; 0.0% of its September days topped AQI 100 versus 2.7% nationally (below average).
September is part of Trenton's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Trenton
The latest EPA AirNow observation puts Trenton's AQI at 52 (PM2.5). The figures above are multi-year month 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.