Bad Air Days in Suffolk County, New York: 9 a Year
9 bad air days a year
More bad air days than three quarters of monitored counties. Ranked 106 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (3% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in July and June and August. Averaged over 2016 to 2025.
Is a purifier worth it here?
- Ozone drives many bad days here. Purifiers and filters do not remove ozone, so do not buy one for that. Ozone peaks on hot afternoons: exercise outside in the morning.
The record for Suffolk
In 2000 to 2009 this county averaged 23 bad days a year; in 2016 to 2025, 9. The air has improved. The worst recent year was 2023, with 13 bad days on 365 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2023-06-07 | 195 | PM2.5 |
| 2018-07-10 | 172 | Ozone |
| 2017-06-12 | 159 | Ozone |
| 2017-06-13 | 156 | Ozone |
| 2023-06-08 | 155 | PM2.5 |
Most days, not the worst ones
Across 3,653 monitored days from 2016 to 2025, the air in Suffolk County rated Good on 75% of them, close to the 72% typical of monitored counties, and Moderate on 23%. The median day sat at AQI 41; one day in ten went above 61.
The pollutant setting the AQI on an ordinary day here:
- ozone69%2,519 days
- fine particles (PM2.5)31%1,128 days
Suffolk County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 365 | 265 | 95 | 5 | 2 | 41 | 154 |
| 2024 | 366 | 291 | 69 | 6 | 0 | 38 | 133 |
| 2023 | 365 | 278 | 74 | 13 | 2 | 41 | 195 |
| 2022 | 365 | 272 | 85 | 8 | 0 | 42 | 133 |
| 2021 | 365 | 281 | 73 | 11 | 1 | 42 | 154 |
| 2020 | 366 | 282 | 78 | 6 | 0 | 40 | 133 |
| 2019 | 365 | 276 | 80 | 9 | 0 | 43 | 150 |
| 2018 | 365 | 254 | 100 | 11 | 1 | 43 | 172 |
| 2017 | 365 | 271 | 85 | 9 | 2 | 42 | 159 |
| 2016 | 366 | 254 | 104 | 8 | 0 | 43 | 150 |
| 2015 | 365 | 241 | 110 | 14 | 0 | 44 | 150 |
| 2014 | 365 | 244 | 120 | 1 | 0 | 44 | 136 |
| 2013 | 365 | 225 | 131 | 9 | 2 | 46 | 159 |
| 2012 | 365 | 233 | 119 | 13 | 4 | 44 | 174 |
| 2011 | 365 | 201 | 147 | 17 | 5 | 48 | 209 |
| 2010 | 365 | 247 | 93 | 25 | 3 | 44 | 166 |
*2025 may be a partial year in EPA's file.
New York compared
- Queens County6/yr
- Westchester County5/yr
- Bronx County5/yr
- Richmond County5/yr
- New York County5/yr
- Rockland County3/yr
- Erie County3/yr
- Monroe County3/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.