Bad Air Days in Chautauqua County, New York: 2 a Year

2 bad air days a year

About the middle of monitored US counties. Ranked 463 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (5% particle days).

When the bad days come in Chautauqua

Most bad days here fall in June and May and July. Averaged over 2016 to 2025.

Is a purifier worth it here?

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 record for Chautauqua

In 2000 to 2009 this county averaged 22 bad days a year; in 2016 to 2025, 2. The air has improved. The worst recent year was 2023, with 5 bad days on 363 monitored days.

Date	AQI	Main pollutant
2016-05-25	140	Ozone
2022-06-21	140	Ozone
2016-06-11	133	Ozone
2023-06-02	133	Ozone
2017-07-19	129	Ozone

The air on a normal day

Across 3,571 monitored days from 2016 to 2025, the air in Chautauqua County rated Good on 88% of them, more often than the 72% typical of monitored counties, and Moderate on 12%. The median day sat at AQI 37; one day in ten went above 53.

The pollutant setting the AQI on an ordinary day here:

ozone92%3,269 days
fine particles (PM2.5)8%302 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	356	317	38	1	0	36	108
2024	363	326	36	1	0	36	105
2023	363	322	36	5	0	37	133
2022	355	322	29	4	0	36	140
2021	361	300	60	1	0	38	105
2020	363	332	31	0	0	36	93
2019	343	302	40	1	0	38	105
2018	358	300	54	4	0	37	126
2017	346	298	46	2	0	38	129
2016	363	315	45	3	0	37	140
2015	362	290	67	5	0	39	126
2014	357	299	56	2	0	38	112
2013	347	298	48	1	0	37	119
2012	366	280	69	17	2	40	197
2011	365	293	66	6	1	39	159
2010	365	271	78	16	1	40	159

*2025 may be a partial year in EPA's file.

Elsewhere in New York

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.