Bad Air Days in LaPorte County, Indiana: 7 a Year
7 bad air days a year
More bad air days than three quarters of monitored counties. Ranked 161 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (11% particle days).
When the bad days come in LaPorte
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in June and July. Averaged over 2016 to 2025.
What actually helps 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.
Better or worse than it was
In 2000 to 2009 this county averaged 23 bad days a year; in 2016 to 2025, 7. The air has improved. The worst recent year was 2023, with 12 bad days on 365 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2018-05-25 | 161 | Ozone |
| 2020-06-19 | 154 | Ozone |
| 2025-07-31 | 153 | PM2.5 |
| 2017-06-09 | 147 | Ozone |
| 2018-05-28 | 147 | Ozone |
Most days, not the worst ones
Across 3,445 monitored days from 2016 to 2025, the air in LaPorte County rated Good on 76% of them, more often than the 72% typical of monitored counties, and Moderate on 22%. The median day sat at AQI 39; one day in ten went above 64.
The pollutant setting the AQI on an ordinary day here:
- ozone77%2,667 days
- fine particles (PM2.5)23%778 days
LaPorte County by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 365 | 230 | 123 | 12 | 1 | 43 | 153 |
| 2024 | 366 | 257 | 107 | 2 | 0 | 41 | 115 |
| 2023 | 365 | 277 | 76 | 12 | 0 | 39 | 133 |
| 2022 | 365 | 302 | 60 | 3 | 0 | 36 | 133 |
| 2021 | 365 | 282 | 78 | 5 | 0 | 37 | 143 |
| 2020 | 366 | 291 | 68 | 7 | 1 | 38 | 154 |
| 2019 | 364 | 296 | 64 | 4 | 0 | 37 | 126 |
| 2018 | 363 | 288 | 68 | 7 | 1 | 37 | 161 |
| 2017 | 282 | 203 | 71 | 8 | 0 | 42 | 147 |
| 2016 | 244 | 185 | 57 | 2 | 0 | 39 | 112 |
| 2015 | 243 | 177 | 63 | 3 | 0 | 42 | 126 |
| 2014 | 242 | 155 | 82 | 5 | 0 | 45 | 126 |
| 2013 | 242 | 146 | 94 | 2 | 0 | 47 | 126 |
| 2012 | 239 | 131 | 84 | 24 | 6 | 48 | 214 |
| 2011 | 235 | 151 | 69 | 15 | 2 | 43 | 174 |
| 2010 | 242 | 147 | 92 | 3 | 1 | 45 | 151 |
*2025 may be a partial year in EPA's file.
Indiana compared
- Marion County8/yr
- Porter County8/yr
- Lake County7/yr
- St. Joseph County5/yr
- Clark County3/yr
- Elkhart County3/yr
- Floyd County3/yr
- Hamilton 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.