Bad Air Days in Osceola County, Florida: 1 a Year

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 681 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (0% particle days).

The bad-air season here

Most bad days here fall in April and May. 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.

The record for Osceola

In 2000 to 2009 this county averaged 6 bad days a year; in 2016 to 2025, 1. The air has improved. The worst recent year was 2019, with 4 bad days on 364 monitored days.

Date	AQI	Main pollutant
2017-05-10	133	Ozone
2018-04-18	126	Ozone
2017-05-09	122	Ozone
2019-04-22	122	Ozone
2019-04-23	112	Ozone

An ordinary day in Osceola

Across 3,613 monitored days from 2016 to 2025, the air in Osceola County rated Good on 93% of them, more often than the 72% typical of monitored counties, and Moderate on 7%. The median day sat at AQI 35; one day in ten went above 48.

The pollutant setting the AQI on an ordinary day here:

ozone95%3,446 days
fine particles (PM2.5)5%167 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Median AQI	Highest AQI
2025*	365	305	59	1	40	105
2024	349	314	34	1	36	108
2023	356	330	26	0	36	80
2022	364	348	16	0	34	80
2021	355	339	16	0	33	93
2020	366	354	12	0	32	90
2019	364	338	22	4	34	122
2018	365	330	33	2	33	126
2017	363	345	16	2	34	133
2016	366	342	24	0	35	90
2015	357	345	12	0	32	87
2014	348	316	32	0	33	100
2013	358	334	23	1	34	112
2012	354	327	27	0	35	97
2011	364	320	43	1	34	108
2010	365	327	36	2	36	133

*2025 may be a partial year in EPA's file.

Florida compared

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.