Williamsport, Pennsylvania Air Quality
Williamsport has a median AQI of 43, earning an air quality grade of A- — excellent air quality that ranks better than 39% of US cities. Air quality has been trending worse over the past decade, a concern for local residents and health officials. Ground-level ozone is the primary concern, typically peaking on warm sunny days due to vehicle and industrial emissions. In 2025, Williamsport recorded 152 good air quality days (73% of monitored days) and 1 unhealthy days.
Population: 27,612 • County: Lycoming
Current AQI
Quick Facts
| Current AQI | 13 — Good |
| Air Quality Grade | A- |
| Median AQI (2025) | 43 |
| vs. U.S. Cities | Better than 39% |
| Primary Pollutant | Ozone |
| Unhealthy Days/Year | 1 |
| 10-Year Trend | ↓ Worsening |
| Data Source | EPA AQS (historical) · AirNow (live) |
Health Recommendation
Air quality is satisfactory, and air pollution poses little or no risk.
It's a great day to be active outside!
5-Day AQI Forecast
Last 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for Williamsport is sourced from the Salladasburg monitoring area, located approximately 10 miles from city center. This EPA-certified station continuously tracks ground-level ozone, the primary driver of air quality alerts in this area.
Williamsport has relatively consistent air quality throughout the year without a strong seasonal peak. Air quality is primarily influenced by local traffic, industrial activity, and regional weather patterns rather than a single seasonal driver.
AQI Trend (10 Years)
Air Quality Days by Year
Williamsport Median AQI by Year
Annual EPA air quality data for Williamsport — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 43 | 152 | 1 | 105 | Ozone |
| 2024 | 39 | 281 | 1 | 122 | Ozone |
| 2023 | 38 | 242 | 3 | 119 | Ozone |
| 2022 | 40 | 221 | — | 80 | PM2.5 |
| 2021 | 44 | 221 | 1 | 111 | PM2.5 |
| 2020 | 41 | 283 | 1 | 109 | Ozone |
| 2019 | 37 | 322 | — | 77 | Ozone |
| 2018 | 31 | 327 | — | 97 | Ozone |
| 2017 | 33 | 343 | — | 84 | Ozone |
| 2016 | 34 | 335 | 1 | 108 | Ozone |
Source: EPA Air Quality System (AQS) annual summaries. "Unhealthy Days" includes Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous categories.
2025 Air Quality Summary
Primary Pollutant Days (2025)
Days when each pollutant was the primary driver of AQI. Learn about pollutants →
Frequently Asked Questions About Williamsport Air Quality
What is the air quality in Williamsport today?
The current AQI in Williamsport is 13, rated "Good". Air quality is good — outdoor activity is safe for everyone today. Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Williamsport getting better or worse?
Air quality in Williamsport has been worsening. The median AQI has risen 9 points (from 34 in 2016 to 43 in 2025), a concern for local health officials.
What is the most common air pollutant in Williamsport?
Ozone is the primary air pollutant in Williamsport, responsible for 115 days (56% of monitored days) in 2025. Ground-level ozone forms when sunlight reacts with emissions from vehicles and industry, typically peaking on hot summer afternoons.
How many unhealthy air days does Williamsport have per year?
In 2025, Williamsport recorded 73% good air quality days (152 days) out of 207 monitored days. There were 1 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 105.
What air quality grade does Williamsport receive?
Williamsport receives an air quality grade of A-, placing it better than 39% of US cities. This is based on a median AQI of 43 in 2025, with 152 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 39% of US cities
Nearby Cities
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National Rankings
See how Williamsport compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Williamsport
Ozone is Williamsport's primary pollutant. Standard HEPA filters don't capture ozone molecules — you need activated carbon or PECO technology to chemically break them down. We highlight those units here.
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