Heilwood, Pennsylvania Air Quality
Heilwood has a median AQI of 42, earning an air quality grade of A- — excellent air quality that ranks better than 44% 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, Heilwood recorded 143 good air quality days (67% of monitored days) and 1 unhealthy days.
Population: 239 • County: Indiana
Current AQI
Quick Facts
| Current AQI | 16 — Good |
| Air Quality Grade | A- |
| Median AQI (2025) | 42 |
| vs. U.S. Cities | Better than 44% |
| 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 Heilwood is sourced from the Johnstown monitoring area, located approximately 22 miles from city center. This EPA-certified station continuously tracks ground-level ozone, the primary driver of air quality alerts in this area.
Heilwood 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
Heilwood Median AQI by Year
Annual EPA air quality data for Heilwood — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 42 | 143 | 1 | 122 | Ozone |
| 2024 | 37 | 291 | — | 74 | Ozone |
| 2023 | 41 | 264 | 7 | 220 | PM2.5 |
| 2022 | 42 | 264 | 1 | 105 | PM2.5 |
| 2021 | 44 | 218 | 2 | 122 | PM2.5 |
| 2020 | 37 | 320 | 1 | 112 | Ozone |
| 2019 | 38 | 324 | — | 93 | Ozone |
| 2018 | 35 | 322 | 1 | 105 | Ozone |
| 2017 | 38 | 315 | — | 100 | Ozone |
| 2016 | 38 | 309 | 4 | 136 | 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 Heilwood Air Quality
What is the air quality in Heilwood today?
The current AQI in Heilwood is 16, 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 Heilwood getting better or worse?
Air quality in Heilwood has been worsening. The median AQI has risen 4 points (from 38 in 2016 to 42 in 2025), a concern for local health officials.
What is the most common air pollutant in Heilwood?
Ozone is the primary air pollutant in Heilwood, responsible for 114 days (54% 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 Heilwood have per year?
In 2025, Heilwood recorded 67% good air quality days (143 days) out of 212 monitored days. There were 1 Unhealthy for Sensitive Groups days and 0 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 122.
What air quality grade does Heilwood receive?
Heilwood receives an air quality grade of A-, placing it better than 44% of US cities. This is based on a median AQI of 42 in 2025, with 143 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 44% of US cities
Nearby Cities
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National Rankings
See how Heilwood compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Heilwood
Ozone is Heilwood'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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