Median AQI
38
Good
New Jersey · County air quality · 2025
Morris County, New Jersey
Median AQI 38 (Good). 87.8% of monitored days rated Good, direct from EPA Air Quality System stations.
- 38
- Median AQI
- 87.8%
- Good-air days
- 0
- Unhealthy days
- 71%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Morris County's air is good on balance, cleaner than the median US county, a median AQI of 38 with 87.8% of 180 monitored days in the Good band, driven mainly by Ozone.
- 38
- median AQI · Good
- 87.8%
- days rated Good
- Ozone
- main pollutant
- 71%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 115.
Data updated July 2026
- Good · 158 d · 87.8%
- Moderate · 20 d · 11.1%
- USG · 2 d · 1.1%
How did Morris County's air break down in 2025?
Across 180 monitored days, 158 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 115 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 180 days monitored. Median AQI: 38 (Good).
Insights: Morris County, New Jersey. EPA monitors recorded a median Air Quality Index of 38 across 180 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 158 (88%) fell in the Good band (AQI 0–50), 20 (11%) registered Moderate readings, and 2 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 55, while the worst single-day peak hit 115 (USG). Residents averaged about 26.3 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (163 days), PM2.5 (15 days), NO2 (2 days). Across the 2020–2025 trend window, good days shifted by -183 and the median AQI moved +3 points, placing the multi-year trajectory at worsening. The worst single reading over the 2020–2025 window was AQI 115, usg but never Unhealthy. Nearby counties show comparable readings: Atlantic (79.6% good, AQI 38); Bergen (71.1% good, AQI 40); Camden (69.4% good, AQI 44); Cumberland (73.0% good, AQI 42); Gloucester (72.4% good, AQI 43); Hudson (74.7% good, AQI 41).
Air Quality Summary
Good Days
87.8%
158 of 180 monitored days
12.8pp vs 75% target
Max AQI Recorded
115
USG
Health Grade
Good
90th-pct AQI 55
Morris County, Good days share 87.8%
National avg
Share of monitored days at AQI 0-50 (Good band).
Morris County, Unhealthy-or-worse share 0.0%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 180 monitored days across EPA AQI categories.
Good
158
88%
Moderate
20
11%
USG
2
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Morris County.
- Ozone · 163 days · 90.6%
- PM2.5 · 15 days · 8.3%
- NO₂ · 2 days · 1.1%
Health Impact Assessment
Good
Morris County's air quality is rated Good based on 87.8% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 87.8% of monitored days in 2025, with a median AQI of 38. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 163 of 180 monitored days.
5-Year Air Quality Trend
Air quality is worsening in Morris County. Best year: 2020 (341 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 341 | 25 | 0 | 0 | 35 | 84 |
| 2021 | 327 | 36 | 0 | 0 | 36 | 97 |
| 2022 | 320 | 40 | 0 | 0 | 36 | 84 |
| 2023 | 314 | 43 | 4 | 2 | 37 | 154 |
| 2024 | 305 | 59 | 2 | 0 | 37 | 108 |
| 2025 | 158 | 20 | 2 | 0 | 38 | 115 |
How does Morris County compare?
How Morris County compares
Good-day share better than US avg
Morris County 87.8%
Atlantic County, New Jersey 79.6%
US average 76.5%
Median AQI about average
Morris County 38
Atlantic County, New Jersey 38
US average 38
Unhealthy days / yr about average
Morris County 0
Atlantic County, New Jersey 0
US average 0
Other Counties in New Jersey
Air quality comparison for nearby counties in New Jersey.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Morris County.
Adams County, Illinois
AQI 38 · 94.4% good
Anoka County, Minnesota
AQI 38 · 82.1% good
Atlantic County, New Jersey
AQI 38 · 79.6% good
Avery County, North Carolina
AQI 38 · 93.9% good
Barnstable County, Massachusetts
AQI 38 · 92.5% good
Bay County, Michigan
AQI 38 · 71.8% good
What Morris County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 38 means for exposure. Health guidance
- See how Morris County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Morris County with its New Jersey neighbours before drawing a conclusion about the region. All of New Jersey
Based on 180 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Morris County, New Jersey? ▼
Morris County has a median Air Quality Index (AQI) of 38, rated "Good." 87.8% of monitored days (158 out of 180) had good air quality in 2025.
What is the main pollutant in Morris County? ▼
The primary pollutant in Morris County is Ozone (O3), which was the main AQI driver on 163 days (91% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Morris County have? ▼
In 2025, Morris County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 115.
Is the air quality in Morris County getting better or worse? ▼
Air quality in Morris County is worsening based on 5-year trends (2020-2025). Best year: 2020 with 341 good days. Worst year: 2025 with 158 good days.
What does AQI 38 mean for health? ▼
Morris County's median AQI of 38 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Morris County compare to other counties in New Jersey? ▼
Morris County has 87.8% good air days. Nearby counties in New Jersey: Atlantic (79.6% good), Bergen (71.1% good), Camden (69.4% good), Cumberland (73.0% good), Gloucester (72.4% good), Hudson (74.7% good).
What is the 90th percentile AQI in Morris County? ▼
The 90th percentile AQI for Morris County is 55, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 115 (USG).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.