Bad Air Days in Belmont County, Ohio: under 1 a Year
under 1 bad air days a year
Rare: among the cleanest-air counties EPA monitors. Ranked 915 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly particles: smoke and dust (100% particle days).
The bad-air season here
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in March and June. Averaged over 2016 to 2025.
What to buy, and what not to
- Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
- On the odd bad day, check AirNow and keep windows shut.
The worst days on file
The worst recent year was 2025, with 1 bad day on 181 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2023-06-29 | 181 | PM2.5 |
| 2025-03-14 | 123 | PM10 |
| 2016-04-18 | 100 | PM10 |
| 2023-07-17 | 98 | PM2.5 |
| 2025-06-13 | 97 | PM2.5 |
An ordinary day in Belmont
Across 3,450 monitored days from 2016 to 2025, the air in Belmont County rated Good on 87% of them, more often than the 72% typical of monitored counties, and Moderate on 13%. The median day sat at AQI 20; one day in ten went above 50.
The pollutant setting the AQI on an ordinary day here:
- nitrogen dioxide58%1,987 days
- fine particles (PM2.5)40%1,364 days
- coarse dust (PM10)2%80 days
- carbon monoxide1%19 days
Belmont County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 181 | 114 | 66 | 1 | 0 | 42 | 123 |
| 2024 | 366 | 289 | 77 | 0 | 0 | 32 | 77 |
| 2023 | 353 | 288 | 64 | 1 | 1 | 31 | 181 |
| 2022 | 360 | 338 | 22 | 0 | 0 | 15 | 64 |
| 2021 | 363 | 320 | 43 | 0 | 0 | 14 | 77 |
| 2020 | 366 | 347 | 19 | 0 | 0 | 13 | 69 |
| 2019 | 365 | 327 | 38 | 0 | 0 | 15 | 69 |
| 2018 | 365 | 331 | 34 | 0 | 0 | 18 | 72 |
| 2017 | 365 | 333 | 32 | 0 | 0 | 16 | 77 |
| 2016 | 366 | 320 | 46 | 0 | 0 | 17 | 100 |
| 2015 | 184 | 162 | 22 | 0 | 0 | 17 | 79 |
*2025 may be a partial year in EPA's file.
Nearby counties on file
- Hamilton County9/yr
- Cuyahoga County7/yr
- Lucas County7/yr
- Lake County7/yr
- Butler County6/yr
- Warren County5/yr
- Geauga County5/yr
- Ashtabula County4/yr
How this is counted
A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day.