Bad Air Days in Erie County, Pennsylvania: 1 a Year

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 618 of 996 monitored counties, where 1 is worst.

What makes them bad: a mix of particles and ozone (54% particle days).

The bad-air season here

Most bad days here fall in June and May and July. 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 17 bad days a year; in 2016 to 2025, 1. The air has improved. The worst recent year was 2023, with 9 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-06-28	180	PM2.5
2023-06-30	154	PM2.5
2023-07-17	152	PM2.5
2025-08-04	149	PM2.5
2023-06-27	137	PM2.5

An ordinary day in Erie

Across 3,613 monitored days from 2016 to 2025, the air in Erie County rated Good on 72% of them, close to the 72% typical of monitored counties, and Moderate on 27%. The median day sat at AQI 40; one day in ten went above 59.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)52%1,884 days
ozone46%1,653 days
nitrogen dioxide2%57 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	280	84	1	0	34	149
2024	366	295	71	0	0	38	93
2023	365	240	116	9	3	42	180
2022	365	286	79	0	0	38	90
2021	329	255	74	0	0	38	92
2020	363	298	65	0	0	36	87
2019	364	271	93	0	0	39	93
2018	365	224	141	0	0	44	84
2017	365	231	133	1	0	43	122
2016	366	233	131	2	0	44	129
2015	365	221	142	2	0	44	115
2014	359	153	205	1	0	53	101
2013	365	130	235	0	0	55	100
2012	366	147	200	19	3	54	185
2011	365	155	206	4	0	53	136
2010	365	181	175	9	0	51	143

*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.