Shiloh, Pennsylvania Air Quality
Shiloh has a median AQI of 45, earning an air quality grade of A- — excellent air quality that ranks better than 27% of US cities. Air quality has been improving steadily over the past decade, a positive sign for residents. Ground-level ozone is the primary concern, typically peaking on warm sunny days due to vehicle and industrial emissions. In 2025, Shiloh recorded 139 good air quality days (66% of monitored days) and 1 unhealthy days.
Population: 11,246 • County: York
Current AQI
Quick Facts
| Current AQI | 23 — Good |
| Air Quality Grade | A- |
| Median AQI (2025) | 45 |
| vs. U.S. Cities | Better than 27% |
| Primary Pollutant | Ozone |
| Unhealthy Days/Year | 1 |
| 10-Year Trend | ↑ Improving |
| 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 Shiloh is sourced from the York monitoring area, located approximately 5 miles from city center. This EPA-certified station continuously tracks ground-level ozone, the primary driver of air quality alerts in this area.
Shiloh 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
Shiloh Median AQI by Year
Annual EPA air quality data for Shiloh — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 45 | 139 | 1 | 101 | Ozone |
| 2024 | 44 | 240 | 1 | 101 | Ozone |
| 2023 | 48 | 198 | 8 | 256 | PM2.5 |
| 2022 | 47 | 205 | 1 | 105 | PM2.5 |
| 2021 | 51 | 168 | 2 | 148 | PM2.5 |
| 2020 | 46 | 221 | — | 97 | PM2.5 |
| 2019 | 44 | 232 | — | 94 | PM2.5 |
| 2018 | 45 | 206 | 1 | 101 | PM2.5 |
| 2017 | 47 | 198 | — | 93 | PM2.5 |
| 2016 | 51 | 176 | 5 | 133 | PM2.5 |
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 Shiloh Air Quality
What is the air quality in Shiloh today?
The current AQI in Shiloh is 23, 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 Shiloh getting better or worse?
Air quality in Shiloh has been improving. The median AQI has dropped 6 points (from 51 in 2016 to 45 in 2025), a positive trend for residents.
What is the most common air pollutant in Shiloh?
Ozone is the primary air pollutant in Shiloh, responsible for 116 days (55% 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 Shiloh have per year?
In 2025, Shiloh recorded 66% good air quality days (139 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 101.
What air quality grade does Shiloh receive?
Shiloh receives an air quality grade of A-, placing it better than 27% of US cities. This is based on a median AQI of 45 in 2025, with 139 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 27% of US cities
Nearby Cities
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National Rankings
See how Shiloh compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Shiloh
Ozone is Shiloh'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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