Trenton Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Trenton (Trenton, NJ area) was June 7, 2023, when the daily AQI reached 244 (Very Unhealthy), set by fine particulate matter (PM2.5), in wildfire smoke season. Across 2,557 monitored days in 2019–2025, 5 of the 10 worst days were Unhealthy (AQI 151+) or worse; 5 of the 10 were driven by ground-level ozone and 5 by fine particulate matter (PM2.5), and 6 of them fell in 2023. The cleanest day was October 26, 2020 at AQI 16 (Good); the 10 best days span 5 different years.
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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When were Trenton's worst and best air quality days?
Worst: June 7, 2023, AQI 244 (Very Unhealthy, PM2.5). Best: October 26, 2020, AQI 16 (Good). Based on 2,557 EPA-monitored days in the Trenton, NJ area, 2019–2025.
- ✓5 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 130 (Unhealthy for Sensitive Groups).
- ✓Ground-level ozone drove 5 of the 10 worst days.
- ✓2023 accounts for 6 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Trenton?▾
June 7, 2023: the Trenton, NJ area's daily AQI hit 244 (Very Unhealthy), driven by fine particulate matter (PM2.5), in wildfire smoke season. That is the highest of 2,557 monitored days in 2019–2025.
What was the best air quality day in Trenton?▾
October 26, 2020, with a daily AQI of 16 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Trenton's worst air quality day in 2025?▾
July 30, 2025, AQI 126 (Unhealthy for Sensitive Groups), set by ground-level ozone, in peak ozone season.
Which pollutant causes Trenton's worst air days?▾
Ground-level ozone set the AQI on 5 of the 10 worst days; fine particulate matter (PM2.5) on 5. The tables above list the defining pollutant for every day.
Trenton's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Trenton, NJ area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2023 page) | 244 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 2 | (2023 page) | 183 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 3 | (2023 page) | 182 | Unhealthy | O3 — ground-level ozone, in peak ozone season |
| 4 | (2023 page) | 159 | Unhealthy | O3 — ground-level ozone, in peak ozone season |
| 5 | (2023 page) | 155 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 6 | (2023 page) | 141 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 7 | (2019 page) | 136 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 8 | (2024 page) | 133 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 9 | (2024 page) | 133 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 10 | (2021 page) | 130 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
Worst day of each year in Trenton
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 136 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2020 | 112 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2021 | 130 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2022 | 119 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2023 | 244 | Very Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2024 | 133 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season | |
| 2025 | 126 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
Trenton's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Trenton, NJ area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2020 page) | 16 | Good | O3 — ground-level ozone |
| 2 | (2019 page) | 17 | Good | O3 — ground-level ozone |
| 3 | (2024 page) | 18 | Good | O3 — ground-level ozone |
| 4 | (2020 page) | 18 | Good | O3 — ground-level ozone |
| 5 | (2020 page) | 18 | Good | O3 — ground-level ozone |
| 6 | (2020 page) | 18 | Good | O3 — ground-level ozone, in peak ozone season |
| 7 | (2024 page) | 19 | Good | O3 — ground-level ozone |
| 8 | (2024 page) | 19 | Good | O3 — ground-level ozone |
| 9 | (2023 page) | 19 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 10 | (2022 page) | 19 | Good | O3 — ground-level ozone |
Right now in Trenton
The latest EPA AirNow observation puts Trenton's AQI at 52 (PM2.5). The days above are historical records, 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.