Casstown, Ohio Air Quality
Casstown has a median AQI of 41, earning an air quality grade of A- — excellent air quality that ranks better than 50% of US cities. Air quality has remained relatively stable over the past decade. Ground-level ozone is the primary concern, typically peaking on warm sunny days due to vehicle and industrial emissions. In 2025, Casstown recorded 173 good air quality days (83% of monitored days) and 1 unhealthy days.
Population: 259 • County: Miami
Current AQI
Quick Facts
| Current AQI | 17 — Good |
| Air Quality Grade | A- |
| Median AQI (2025) | 41 |
| vs. U.S. Cities | Better than 50% |
| Primary Pollutant | Ozone |
| Unhealthy Days/Year | 1 |
| 10-Year Trend | → Stable |
| 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 Casstown is sourced from the Springfield Fire St1 monitoring area, located approximately 19 miles from city center. This EPA-certified station continuously tracks ground-level ozone, the primary driver of air quality alerts in this area.
Casstown typically sees its worst air quality during summer afternoons when heat and sunlight drive ground-level ozone formation from vehicle and industrial emissions. Morning readings are generally 15–25 points lower than afternoon peaks. Outdoor activity is best planned for early morning on high-ozone days.
AQI Trend (10 Years)
Air Quality Days by Year
Casstown Median AQI by Year
Annual EPA air quality data for Casstown — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 41 | 173 | 1 | 101 | Ozone |
| 2024 | 43 | 198 | 1 | 101 | Ozone |
| 2023 | 43 | 193 | 3 | 112 | Ozone |
| 2022 | 39 | 214 | 2 | 122 | Ozone |
| 2021 | 40 | 215 | — | 87 | Ozone |
| 2020 | 39 | 217 | — | 93 | Ozone |
| 2019 | 40 | 226 | — | 77 | Ozone |
| 2018 | 40 | 207 | 1 | 140 | Ozone |
| 2017 | 40 | 210 | 1 | 101 | Ozone |
| 2016 | 43 | 164 | 3 | 101 | 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 Casstown Air Quality
What is the air quality in Casstown today?
The current AQI in Casstown is 17, 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 Casstown getting better or worse?
Air quality in Casstown has been stable. The median AQI has dropped 2 points (from 43 in 2016 to 41 in 2025).
What is the most common air pollutant in Casstown?
Ozone is the primary air pollutant in Casstown, responsible for 209 days (100% 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 Casstown have per year?
In 2025, Casstown recorded 83% good air quality days (173 days) out of 209 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 Casstown receive?
Casstown receives an air quality grade of A-, placing it better than 50% of US cities. This is based on a median AQI of 41 in 2025, with 173 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 50% of US cities
Nearby Cities
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National Rankings
See how Casstown compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Casstown
Casstown has a summer ozone problem — hot afternoons push AQI into Moderate or higher as sunlight converts vehicle and industrial emissions into ground-level ozone. Activated carbon and PECO filters chemically neutralize ozone rather than just trapping particles.
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