Bad Air Days in Spartanburg County, South Carolina: 2 a Year

2 bad air days a year

Fewer bad air days than most monitored US counties. Ranked 549 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (24% particle days).

Which months to watch

Most bad days here fall in July and June. 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 worst days on file

In 2000 to 2009 this county averaged 28 bad days a year; in 2016 to 2025, 2. The air has improved. The worst recent year was 2023, with 5 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-07-18	136	PM2.5
2016-06-10	126	Ozone
2016-05-25	122	Ozone
2021-07-25	119	PM2.5
2023-07-17	118	PM2.5

An ordinary day in Spartanburg

Across 3,591 monitored days from 2016 to 2025, the air in Spartanburg County rated Good on 55% of them, less often than the 72% typical of monitored counties, and Moderate on 44%. The median day sat at AQI 47; one day in ten went above 63.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)71%2,544 days
ozone29%1,047 days

Spartanburg County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	201	164	0	0	48	93
2024	363	188	171	4	0	49	112
2023	365	166	194	5	0	51	136
2022	363	206	157	0	0	47	87
2021	354	201	152	1	0	46	119
2020	366	232	132	2	0	45	112
2019	348	206	140	2	0	45	105
2018	365	223	142	0	0	44	77
2017	351	197	153	1	0	48	108
2016	351	161	188	2	0	52	126
2015	364	187	177	0	0	49	97
2014	364	180	183	1	0	51	116
2013	356	182	173	1	0	49	105
2012	359	140	219	0	0	53	93
2011	365	122	230	13	1	57	156
2010	361	122	221	18	0	56	140

*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.