Erie County, Pennsylvania air quality history

Daily Air Quality Index summaries from EPA monitors in Erie, Pennsylvania, 1980–2025.

77%

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 Erie, Pennsylvania on 365 days. 280 of those days (77%) were in the Good range, and the median daily AQI was 34. That median is lower than the typical monitored county in Pennsylvania (median 40 across 38 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 228 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 75% in 1980–1982 versus 74% 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
Fine particles (PM2.5)	228	62%
Ozone	120	33%
Nitrogen dioxide (NO₂)	16	4%
Carbon monoxide (CO)	1	<1%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Very Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
2025	365	280	84	1	0	0	34	59	149	PM2.5
2024	366	295	71	0	0	0	38	56	93	Ozone
2023	365	240	116	6	3	0	42	64	180	PM2.5
2022	365	286	79	0	0	0	38	56	90	PM2.5
2021	329	255	74	0	0	0	38	57	92	PM2.5
2020	363	298	65	0	0	0	36	54	87	Ozone
2019	364	271	93	0	0	0	39	56	93	PM2.5
2018	365	224	141	0	0	0	44	63	84	PM2.5
2017	365	231	133	1	0	0	43	61	122	PM2.5
2016	366	233	131	2	0	0	44	60	129	PM2.5
2015	365	221	142	2	0	0	44	66	115	PM2.5
2014	359	153	205	1	0	0	53	67	101	PM2.5
2013	365	130	235	0	0	0	55	72	100	PM2.5
2012	366	147	200	16	3	0	54	80	185	PM2.5
2011	365	155	206	4	0	0	53	72	136	PM2.5
2010	365	181	175	9	0	0	51	76	143	PM2.5
2009	365	208	153	4	0	0	47	66	140	PM2.5
2008	366	164	196	5	1	0	52	74	158	PM2.5
2007	365	177	166	20	2	0	51	85	182	PM2.5
2006	365	176	178	10	1	0	51	78	161	PM2.5
2005	365	130	202	27	6	0	56	97	195	PM2.5
2004	366	162	192	12	0	0	53	81	143	PM2.5
2003	365	160	192	9	3	1	53	81	204	PM2.5
2002	365	152	183	13	17	0	53	90	195	PM2.5
2001	365	160	176	25	4	0	54	93	185	PM2.5
2000	366	278	78	8	2	0	39	71	177	Ozone
1999	365	241	81	31	11	1	40	108	205	Ozone
1998	365	271	54	29	9	2	37	108	210	Ozone
1997	361	308	34	15	4	0	36	80	179	NO2
1996	348	289	46	10	3	0	34	77	169	Ozone
1995	357	276	55	19	6	1	37	84	208	NO2
1994	365	280	57	21	7	0	39	87	174	NO2
1993	365	280	64	18	3	0	38	87	164	Ozone
1992	366	310	45	8	3	0	36	67	197	Ozone
1991	365	295	42	19	9	0	35	90	197	Ozone
1990	364	287	49	25	3	0	37	80	161	Ozone
1989	365	287	51	17	8	2	38	90	205	Ozone
1988	365	249	65	26	19	6	40	140	222	Ozone
1987	365	281	54	19	10	1	40	90	217	Ozone
1986	365	277	65	21	2	0	38	80	169	Ozone
1985	365	271	73	17	4	0	40	84	190	Ozone
1984	366	305	52	8	1	0	38	61	161	Ozone
1983	365	283	48	19	10	5	37	87	225	Ozone
1982	362	256	87	11	8	0	38	79	195	NO2
1981	336	281	34	13	7	1	33	74	208	NO2
1980	330	234	48	24	18	6	40	136	256	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 Pennsylvania with a similar median AQI in 2025

All monitored counties in Pennsylvania

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