Air Quality in Johnstown, PA: Moderate (52 AQI)
AQI 52 · Moderate · Ozone · Updated 2026-05-03
Johnstown's air quality is moderate. Unusually sensitive people should consider reducing prolonged outdoor exertion.
Data: EPA AirNow, FEMA National Risk Index Last verified: 2026-05-03
What is AQI?
The Air Quality Index (AQI) is a standardized scale from 0 to 500 that measures air pollution levels. 0-50 is "Good," 51-100 is "Moderate," 101-150 is "Unhealthy for Sensitive Groups," and above 150 is "Unhealthy" for everyone. AQI tracks five major pollutants: ground-level ozone, particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide. Johnstown's average AQI of 52 falls in the "Moderate" range.
Air Quality Map: Johnstown, PA
Each dot represents a ZIP code. Color indicates AQI level. Tap a dot for details.
Air Quality by ZIP Code in Johnstown
AQI varies across Johnstown's 8 ZIP codes based on proximity to pollution sources and local geography.
| ZIP Code | AQI | Category | Wildfire | Mold | |
|---|---|---|---|---|---|
| 15901 | 52 | Moderate | 11 | 72 | View report → |
| 15902 | 52 | Moderate | 11 | 72 | View report → |
| 15904 | 52 | Moderate | 11 | 61 | View report → |
| 15905 | 52 | Moderate | 11 | 72 | View report → |
| 15906 | 52 | Moderate | 11 | 75 | View report → |
| 15907 | 52 | Moderate | 11 | 49 | View report → |
| 15909 | 52 | Moderate | 11 | 63 | View report → |
| 15915 | 52 | Moderate | 11 | 44 | View report → |
Air Quality Overview
Johnstown, Pennsylvania has moderate air quality with an average AQI of 52. Air quality is acceptable, though some pollutants may be a concern for a small number of people who are unusually sensitive to air pollution. The dominant pollutant is Ozone.
The Air Quality Index (AQI) is an EPA-standardized scale from 0 to 500. Values below 50 are "Good," 51-100 "Moderate," 101-150 "Unhealthy for Sensitive Groups," 151-200 "Unhealthy," 201-300 "Very Unhealthy," and above 300 "Hazardous."
Dominant Pollutant: Ozone
Ground-level ozone forms when pollutants from cars, power plants, and industrial facilities react with sunlight. Unlike stratospheric ozone, ground-level ozone is harmful to breathe.
Health effects of ozone exposure:
- Irritation of the respiratory system
- Reduced lung function
- Aggravation of asthma and chronic lung diseases
- Increased susceptibility to respiratory infections
Peak times: Ozone levels are typically highest on hot, sunny afternoons. Exercise outdoors in the morning when levels are lower.
Air Quality by ZIP Code in Johnstown
AQI varies across Johnstown's 8 ZIP codes based on proximity to pollution sources, traffic patterns, and local geography:
| ZIP Code | AQI | Category | Wildfire Risk | Mold Score |
|---|---|---|---|---|
| 15901 | 52 | Moderate | 11 | 72 |
| 15902 | 52 | Moderate | 11 | 72 |
| 15904 | 52 | Moderate | 11 | 61 |
| 15905 | 52 | Moderate | 11 | 72 |
| 15906 | 52 | Moderate | 11 | 75 |
| 15907 | 52 | Moderate | 11 | 49 |
| 15909 | 52 | Moderate | 11 | 63 |
| 15915 | 52 | Moderate | 11 | 44 |
Wildfire Smoke Risk
Johnstown has an elevated wildfire smoke risk with an average smoke risk score of 11 (scale 0-100). There have been 8 fires recorded within 100 km of city ZIP codes.
| Metric | Value |
|---|---|
| Avg. smoke risk score | 11 |
| Max smoke risk score | 11 |
| Fires within 100 km | 8 |
| High-risk ZIP codes | 0 |
Wildfire smoke contains PM2.5, carbon monoxide, and volatile organic compounds. Even short-term exposure can trigger asthma attacks and respiratory distress.
Indoor Mold Risk
Johnstown has an average mold risk score of 64 out of 100, with 6 ZIP codes in the high-risk category.
| Factor | Value |
|---|---|
| Mold risk score | 64/100 |
| Average humidity | 68% RH |
| High-risk ZIPs | 6 |
| Peak season | summer high |
Mold risk is influenced by humidity levels, housing age (older homes have more moisture issues), flood history, and water infrastructure quality. Indoor humidity above 60% creates favorable conditions for mold growth.
Signs of mold problems: musty odors, visible growth on walls or ceilings, worsening allergies indoors, condensation on windows. Professional mold testing ($300-$600) can identify hidden issues.
Health Recommendations
With moderate air quality (AQI 52), most people can be active outdoors. Sensitive groups should take precautions:
- Sensitive groups (asthma, COPD, heart disease): consider reducing prolonged outdoor exertion
- Keep windows closed on high-pollution days
- Use a HEPA air purifier in main living areas
- Check AirNow.gov before outdoor exercise
Johnstown vs. Nearby Pennsylvania Cities
How Johnstown's air quality compares to nearby cities:
| City | AQI | Category | Population |
|---|---|---|---|
| Johnstown | 52 | Moderate | 80,392 |
| State College | 60 | Moderate | 78,220 |
| Gwynedd | 61 | Moderate | 72,496 |
| Montgomeryville | 61 | Moderate | 72,496 |
ZIP Codes in Johnstown
Johnstown covers 8 ZIP codes. Air quality can vary by neighborhood based on proximity to highways, industrial areas, and green spaces. Check your specific ZIP code for localized data.
Data Sources
- Air quality: EPA AirNow — real-time and historical AQI data
- Wildfire risk: FEMA National Risk Index
- Mold risk: Derived from EPA, FEMA, Census ACS (humidity, housing age, flood history)
- Monthly AQI: EPA Air Quality Statistics
Updated daily.