Bad Air Days in Miami-Dade County, Florida: 3 a Year
3 bad air days a year
About the middle of monitored US counties. Ranked 432 of 996 monitored counties, where 1 is worst.
What makes them bad: a mix of particles and ozone (56% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in January and March and May and December. Averaged over 2016 to 2025.
What actually helps 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 7 bad days a year; in 2016 to 2025, 3. The air has improved. The worst recent year was 2017, with 4 bad days on 354 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2024-01-01 | 197 | PM2.5 |
| 2024-02-09 | 190 | PM2.5 |
| 2023-01-01 | 170 | PM2.5 |
| 2024-02-27 | 162 | PM2.5 |
| 2023-12-31 | 156 | PM2.5 |
Most days, not the worst ones
Across 3,634 monitored days from 2016 to 2025, the air in Miami-Dade County rated Good on 58% of them, less often than the 72% typical of monitored counties, and Moderate on 41%. The median day sat at AQI 47; one day in ten went above 62.
The pollutant setting the AQI on an ordinary day here:
- fine particles (PM2.5)79%2,871 days
- ozone19%678 days
- nitrogen dioxide2%81 days
Miami-Dade County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 365 | 206 | 158 | 1 | 0 | 47 | 113 |
| 2024 | 366 | 219 | 143 | 4 | 3 | 48 | 197 |
| 2023 | 365 | 207 | 155 | 3 | 3 | 48 | 170 |
| 2022 | 365 | 259 | 104 | 2 | 0 | 44 | 136 |
| 2021 | 365 | 230 | 133 | 2 | 0 | 46 | 135 |
| 2020 | 366 | 226 | 140 | 0 | 0 | 45 | 90 |
| 2019 | 363 | 245 | 116 | 2 | 0 | 44 | 146 |
| 2018 | 365 | 194 | 167 | 4 | 0 | 49 | 126 |
| 2017 | 354 | 177 | 173 | 4 | 0 | 51 | 136 |
| 2016 | 360 | 153 | 204 | 3 | 0 | 52 | 144 |
| 2015 | 365 | 201 | 164 | 0 | 0 | 49 | 87 |
| 2014 | 365 | 161 | 203 | 1 | 0 | 52 | 123 |
| 2013 | 365 | 189 | 174 | 2 | 0 | 49 | 119 |
| 2012 | 366 | 144 | 220 | 2 | 0 | 52 | 136 |
| 2011 | 365 | 154 | 207 | 4 | 0 | 52 | 129 |
| 2010 | 365 | 126 | 235 | 4 | 0 | 53 | 150 |
*2025 may be a partial year in EPA's file.
Florida compared
- Hillsborough County3/yr
- Duval County2/yr
- Broward County1/yr
- Osceola County1/yr
- Orange Countyunder 1/yr
- Polk Countyunder 1/yr
- Pinellas Countyunder 1/yr
- Seminole 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.