Lexington County, South Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Lexington, South Carolina, 1980–2023.

64%

Good days in 2023

Median daily AQI, 2023

Days above 100 in 2023

149

Days with an AQI in 2023 (of 365)

In 2023, EPA reported a daily Air Quality Index (AQI) for Lexington, South Carolina on 149 days. 96 of those days (64%) were in the Good range, and the median daily AQI was 41. That median is lower than the typical monitored county in South Carolina (median 43.5 across 14 counties), and about the same as the typical monitored U.S. county (43). The main pollutant was fine particles (PM2.5) on 140 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 64% in 1980–1986 versus 64% in 2021–2023.

EPA did not report an AQI for every day of 2023 here (149 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

The most recent year with data for this county is 2023; EPA's files for 2024–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1989, 1990, 1991) are shown in the table but left out of comparisons and trend statements.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median daily AQI
90th-percentile daily AQI

Main pollutant by day, 2023

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

Pollutant	Days as main pollutant	Share of monitored days
Fine particles (PM2.5)	140	94%
Coarse particles (PM10)	9	6%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
2023	149	96	53	0	0	41	58	77	PM2.5
2022	363	263	100	0	0	39	55	75	PM2.5
2021	358	199	158	1	0	46	63	102	PM2.5
2020	365	263	101	1	0	39	55	111	PM2.5
2019	365	230	135	0	0	44	58	69	PM2.5
2018	362	234	128	0	0	43	58	93	PM2.5
2017	354	220	134	0	0	44	60	85	PM2.5
2016	360	199	159	0	2	47	61	171	PM2.5
2015	365	202	163	0	0	47	59	92	PM2.5
2014	364	184	180	0	0	50	61	74	PM2.5
2013	365	201	164	0	0	47	61	82	PM2.5
2012	366	147	219	0	0	52	64	92	PM2.5
2011	365	119	246	0	0	55	69	96	PM2.5
2010	365	131	234	0	0	54	68	90	PM2.5
2009	365	151	214	0	0	53	66	83	PM2.5
2008	366	174	192	0	0	52	70	85	PM2.5
2007	358	107	251	0	0	57	78	99	PM2.5
2006	349	192	157	0	0	46	70	97	PM10
2005	362	220	139	3	0	43	70	108	PM10
2004	360	212	146	2	0	44	66	119	PM10
2003	303	208	95	0	0	38	63	95	PM10
2002	346	218	127	1	0	41	64	115	PM10
2001	345	191	154	0	0	47	71	96	PM10
2000	352	168	181	3	0	52	76	146	PM10
1999	316	130	182	4	0	55	77	120	PM10
1998	359	249	105	5	0	37	68	132	PM10
1997	343	255	87	1	0	32	61	106	PM10
1996	352	256	96	0	0	35	61	90	PM10
1995	316	235	81	0	0	35	60	97	PM10
1994	332	256	76	0	0	31	58	84	PM10
1993	317	231	86	0	0	37	59	77	PM10
1992	354	273	81	0	0	33	57	82	PM10
1991	96	82	14	0	0	24	53	81	PM10
1990	60	55	5	0	0	25	46	70	PM10
1989	40	37	3	0	0	29	46	64	PM10
1987	130	130	0	0	0	8	17	25	CO
1986	179	179	0	0	0	9	17	30	CO
1981	173	81	58	32	2	54	115	151	Ozone
1980	221	102	68	44	7	58	126	197	Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

All monitored counties in South Carolina

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2023 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem