Trenton Air Quality in December
Across 2019–2025, Trenton's December air quality had a median AQI of 42 (Good) over 217 monitored days in the Trenton, NJ area. 0.0% of December days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 79.7% of days. The cleanest December on record here was 2020 (median AQI 36, 0 days above 100) and the worst was 2021 (median 56, 0 days above 100, peak AQI 72).
- Good: 60.4%
- Moderate: 39.6%
- 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 December?
Good on a typical day: median AQI 42 across 2019–2025, with 0.0% of December days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓60.4% of December days were Good (AQI 0–50), 39.6% Moderate (51–100).
- ✓0 days of 217 reached AQI 101+; the December peak was 96.
- ✓Best December: 2020; worst December: 2021.
Frequently asked questions
What is the air quality like in Trenton in December?▾
Across 2019–2025, the median daily AQI in Trenton in December was 42 (Good). 60.4% of days were Good, 39.6% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is December a good time for outdoor exercise in Trenton?▾
A typical December day in Trenton sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of December days reached AQI 101+ in 2019–2025.
Which pollutant causes Trenton's December air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 79.7% of December days in Trenton. The highest December AQI recorded in 2019–2025 was 96 (Moderate), in 2021.
Trenton December air quality, year by year
Trenton December air quality by year (Trenton, NJ, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 31 | 42 | 0 | 96 | PM2.5 |
| 2020cleanest | 31 | 36 | 0 | 75 | PM2.5 |
| 2021worst | 31 | 56 | 0 | 72 | PM2.5 |
| 2022 | 31 | 41 | 0 | 76 | PM2.5 |
| 2023 | 31 | 47 | 0 | 83 | PM2.5 |
| 2024 | 31 | 39 | 0 | 71 | PM2.5 |
| 2025 | 31 | 36 | 0 | 69 | PM2.5 |
What December air means in Trenton
A typical December day in Trenton sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of December days reached AQI 101+ in 2019–2025.
December's median AQI of 42 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 December AQI across every EPA metro area (95,590 metro-days, 2019–2025) is 39, so Trenton runs in line with the national December norm; 0.0% of its December days topped AQI 100 versus 0.7% nationally (about the same).
December is part of Trenton's winter season (December, January, February); the winter 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.