Bad Air Days in Orange County, Florida: under 1 a Year

under 1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 713 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (11% particle days).

Which months to watch

Most bad days here fall in January and March and April and May. Averaged over 2016 to 2025.

What to buy, and what not to

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 Orange

In 2000 to 2009 this county averaged 11 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2024, with 2 bad days on 360 monitored days.

Date	AQI	Main pollutant
2018-04-18	151	Ozone
2017-05-10	147	Ozone
2024-01-01	121	PM2.5
2023-06-26	115	Ozone
2017-05-11	108	Ozone

Most days, not the worst ones

Across 3,642 monitored days from 2016 to 2025, the air in Orange County rated Good on 77% of them, more often than the 72% typical of monitored counties, and Moderate on 22%. The median day sat at AQI 41; one day in ten went above 55.

The pollutant setting the AQI on an ordinary day here:

ozone62%2,257 days
fine particles (PM2.5)37%1,353 days
nitrogen dioxide1%29 days

Orange County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	266	98	1	0	43	105
2024	360	272	86	2	0	41	121
2023	365	267	96	2	0	43	115
2022	365	317	48	0	0	39	97
2021	365	354	11	0	0	33	87
2020	366	354	12	0	0	34	93
2019	360	293	67	0	0	39	93
2018	365	286	77	2	1	40	151
2017	365	195	168	2	0	49	147
2016	366	214	152	0	0	47	97
2015	365	239	125	1	0	44	101
2014	362	236	125	1	0	45	126
2013	365	254	110	1	0	44	108
2012	366	232	128	6	0	47	140
2011	365	172	183	10	0	51	133
2010	365	172	188	5	0	51	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.