Kern County, California air quality history

Daily Air Quality Index summaries from EPA monitors in Kern, California, 1980–2025.

18%

Good days in 2025

Median daily AQI, 2025

Days above 100 in 2025

365

Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Kern, California on 365 days. 64 of those days (18%) were in the Good range, and the median daily AQI was 70. That median is higher than the typical monitored county in California (median 45.5 across 46 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 196 days. Across the years with fuller monitoring, the share of Good days fell: an average of 28% in 1980–1982 versus 21% in 2023–2025.

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, 2025

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
Ozone	196	54%
Fine particles (PM2.5)	153	42%
Coarse particles (PM10)	16	4%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Very Unhealthy	Hazardous	Median AQI	90th pct.	Max AQI	Main pollutant
2025	365	64	236	61	4	0	0	70	112	200	Ozone
2024	366	76	196	73	21	0	0	72	140	177	Ozone
2023	365	85	210	58	12	0	0	69	122	174	Ozone
2022	365	47	196	109	12	1	0	80	136	289	Ozone
2021	365	35	202	97	29	1	1	84	147	314	PM2.5
2020	366	56	180	98	28	4	0	83	140	267	Ozone
2019	365	91	179	87	6	1	1	69	122	553	Ozone
2018	365	45	190	103	27	0	0	84	142	190	Ozone
2017	365	59	167	115	24	0	0	85	140	197	Ozone
2016	366	46	204	102	14	0	0	80	136	169	Ozone
2015	365	23	220	93	28	1	0	84	146	201	Ozone
2014	365	17	188	117	42	0	1	97	154	307	Ozone
2013	365	14	215	104	31	1	0	90	148	242	PM2.5
2012	366	39	185	92	49	1	0	85	154	202	Ozone
2011	365	39	186	100	40	0	0	84	151	200	Ozone
2010	365	43	197	85	38	2	0	81	151	202	PM2.5
2009	365	17	179	91	73	5	0	97	162	299	PM2.5
2008	366	13	158	107	74	14	0	107	172	217	Ozone
2007	365	14	167	114	66	4	0	101	163	229	PM2.5
2006	365	37	148	95	71	14	0	100	177	217	Ozone
2005	365	29	167	90	72	7	0	93	172	208	Ozone
2004	366	18	141	98	95	14	0	113	185	222	Ozone
2003	365	12	129	100	93	31	0	118	197	223	Ozone
2002	365	11	123	99	114	18	0	125	182	216	Ozone
2001	365	24	137	101	90	13	0	108	179	230	Ozone
2000	366	40	122	95	100	9	0	111	179	213	Ozone
1999	365	57	112	72	108	16	0	108	182	210	Ozone
1998	365	126	102	59	44	34	0	67	200	233	Ozone
1997	365	134	97	77	53	4	0	74	161	214	Ozone
1996	366	128	92	42	61	43	0	74	202	234	Ozone
1995	365	109	100	51	71	34	0	86	197	230	Ozone
1994	365	97	112	54	78	24	0	81	192	225	Ozone
1993	365	88	114	73	63	27	0	89	192	221	Ozone
1992	366	118	93	61	88	6	0	84	174	210	Ozone
1991	365	75	127	62	68	32	1	89	195	422	Ozone
1990	365	61	128	84	66	25	1	100	190	342	Ozone
1989	365	59	132	67	77	30	0	100	192	233	Ozone
1988	366	64	118	63	73	48	0	101	203	223	Ozone
1987	365	91	117	54	71	32	0	79	195	227	Ozone
1986	365	88	117	69	68	23	0	89	187	222	Ozone
1985	365	82	134	62	72	15	0	89	182	217	Ozone
1984	366	125	135	38	56	12	0	61	169	217	NO2
1983	365	131	135	45	48	6	0	61	161	208	NO2
1982	365	109	150	50	51	5	0	68	164	229	NO2
1981	365	99	137	55	45	29	0	74	190	245	NO2
1980	366	97	147	50	45	27	0	74	190	230	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.

Counties in California with a similar median AQI in 2025

All monitored counties in California

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem