Bad Air Days in Tioga County, Pennsylvania: under 1 a Year
under 1 bad air day a year
Rare: among the cleanest-air counties EPA monitors. Ranked 804 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly particles: smoke and dust (60% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in May and August and July. Averaged over 2016 to 2025.
Is a purifier worth it here?
- 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
In 2000 to 2009 this county averaged 22 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2025, with 2 bad days on 364 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2021-07-20 | 131 | PM2.5 |
| 2025-08-04 | 127 | PM2.5 |
| 2025-08-05 | 113 | PM2.5 |
| 2016-05-25 | 112 | Ozone |
| 2016-05-24 | 108 | Ozone |
The air on a normal day
Across 3,471 monitored days from 2016 to 2025, the air in Tioga County rated Good on 78% of them, more often than the 72% typical of monitored counties, and Moderate on 21%. The median day sat at AQI 40; one day in ten went above 56.
The pollutant setting the AQI on an ordinary day here:
- ozone62%2,167 days
- fine particles (PM2.5)37%1,294 days
Tioga County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 364 | 299 | 63 | 2 | 0 | 39 | 127 |
| 2024 | 362 | 316 | 46 | 0 | 0 | 36 | 84 |
| 2023 | 304 | 254 | 50 | 0 | 0 | 41 | 100 |
| 2022 | 302 | 248 | 54 | 0 | 0 | 39 | 77 |
| 2021 | 350 | 274 | 75 | 1 | 0 | 38 | 131 |
| 2020 | 352 | 298 | 54 | 0 | 0 | 39 | 81 |
| 2019 | 361 | 317 | 44 | 0 | 0 | 37 | 77 |
| 2018 | 347 | 286 | 61 | 0 | 0 | 37 | 97 |
| 2017 | 363 | 150 | 213 | 0 | 0 | 53 | 84 |
| 2016 | 366 | 280 | 84 | 2 | 0 | 41 | 112 |
| 2015 | 365 | 224 | 141 | 0 | 0 | 44 | 90 |
| 2014 | 362 | 326 | 36 | 0 | 0 | 38 | 74 |
| 2013 | 365 | 326 | 38 | 1 | 0 | 36 | 112 |
| 2012 | 345 | 294 | 47 | 4 | 0 | 36 | 140 |
| 2011 | 297 | 249 | 46 | 2 | 0 | 40 | 112 |
| 2010 | 214 | 149 | 55 | 10 | 0 | 44 | 140 |
*2025 may be a partial year in EPA's file.
Pennsylvania compared
- Allegheny County12/yr
- Philadelphia County9/yr
- Bucks County8/yr
- Warren Countythin data
- Lancaster County6/yr
- Berks County5/yr
- Delaware County4/yr
- Northampton 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.