Bad Air Days in Marion County, Florida: under 1 a Year
under 1 bad air day a year
Rare: among the cleanest-air counties EPA monitors. Ranked 819 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (0% particle days).
When the bad days come in Marion
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in May and April. 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.
Better or worse than it was
In 2000 to 2009 this county averaged 8 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2017, with 1 bad day on 351 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2016-05-09 | 105 | Ozone |
| 2017-05-09 | 101 | Ozone |
| 2021-04-14 | 101 | Ozone |
| 2024-04-25 | 101 | Ozone |
| 2025-05-23 | 101 | Ozone |
The air on a normal day
Across 3,630 monitored days from 2016 to 2025, the air in Marion County rated Good on 67% of them, less often than the 72% typical of monitored counties, and Moderate on 33%. The median day sat at AQI 44; one day in ten went above 57.
The pollutant setting the AQI on an ordinary day here:
- fine particles (PM2.5)70%2,545 days
- ozone30%1,085 days
Marion County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 364 | 245 | 118 | 1 | 0 | 46 | 101 |
| 2024 | 360 | 189 | 170 | 1 | 0 | 49 | 101 |
| 2023 | 365 | 241 | 124 | 0 | 0 | 45 | 99 |
| 2022 | 363 | 259 | 104 | 0 | 0 | 44 | 93 |
| 2021 | 365 | 257 | 107 | 1 | 0 | 42 | 101 |
| 2020 | 366 | 229 | 137 | 0 | 0 | 46 | 100 |
| 2019 | 365 | 244 | 121 | 0 | 0 | 44 | 88 |
| 2018 | 365 | 273 | 92 | 0 | 0 | 42 | 90 |
| 2017 | 351 | 250 | 100 | 1 | 0 | 43 | 101 |
| 2016 | 366 | 254 | 111 | 1 | 0 | 43 | 105 |
| 2015 | 365 | 275 | 90 | 0 | 0 | 40 | 71 |
| 2014 | 365 | 224 | 141 | 0 | 0 | 45 | 97 |
| 2013 | 365 | 238 | 127 | 0 | 0 | 44 | 90 |
| 2012 | 366 | 209 | 157 | 0 | 0 | 48 | 84 |
| 2011 | 365 | 197 | 164 | 4 | 0 | 48 | 119 |
| 2010 | 365 | 195 | 168 | 2 | 0 | 49 | 112 |
*2025 may be a partial year in EPA's file.
Elsewhere in Florida
- Hillsborough County3/yr
- Miami-Dade County3/yr
- Duval County2/yr
- Broward County1/yr
- Osceola County1/yr
- Orange Countyunder 1/yr
- Polk Countyunder 1/yr
- Pinellas Countyunder 1/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, and on why a purifier does not touch ozone in smoke vs ozone.