Bad Air Days in Sullivan County, Tennessee: under 1 a Year

under 1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 745 of 996 monitored counties, where 1 is worst.

What makes them bad: a mix of particles and ozone (43% particle days).

The bad-air season here

Most bad days here fall in June and July and April and September and November. 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.

Better or worse than it was

In 2000 to 2009 this county averaged 25 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2016, with 3 bad days on 322 monitored days.

Date	AQI	Main pollutant
2016-11-23	127	PM2.5
2019-09-10	119	Ozone
2023-06-29	118	PM2.5
2023-07-17	106	PM2.5
2016-04-20	105	Ozone

An ordinary day in Sullivan

Across 3,554 monitored days from 2016 to 2025, the air in Sullivan County rated Good on 76% of them, more often than the 72% typical of monitored counties, and Moderate on 24%. The median day sat at AQI 41; one day in ten went above 58.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)50%1,773 days
ozone49%1,736 days
nitrogen dioxide1%43 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	361	296	65	0	0	40	90
2024	361	285	76	0	0	41	97
2023	363	277	84	2	0	42	118
2022	364	299	65	0	0	40	87
2021	365	273	92	0	0	41	100
2020	366	314	52	0	0	36	80
2019	362	240	121	1	0	44	119
2018	364	259	104	1	0	43	105
2017	326	218	108	0	0	45	93
2016	322	249	70	3	0	42	127
2015	365	291	74	0	0	39	100
2014	365	283	82	0	0	39	90
2013	365	271	93	1	0	41	101
2012	366	295	61	10	1	38	187
2011	365	292	67	6	0	39	126
2010	365	275	84	6	0	40	133

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

Nearby counties on file

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.