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

2 bad air days a year

Fewer bad air days than most monitored US counties. Ranked 551 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (71% particle days).

Which months to watch

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

What actually helps 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 Onondaga

In 2000 to 2009 this county averaged 10 bad days a year; in 2016 to 2025, 2. The air has improved. The worst recent year was 2023, with 8 bad days on 361 monitored days.

Date	AQI	Main pollutant
2023-06-07	258	PM2.5
2023-06-06	176	PM2.5
2023-06-29	174	PM2.5
2023-06-30	167	PM2.5
2025-08-04	125	PM2.5

Most days, not the worst ones

Across 3,638 monitored days from 2016 to 2025, the air in Onondaga County rated Good on 83% of them, more often than the 72% typical of monitored counties, and Moderate on 17%. The median day sat at AQI 37; one day in ten went above 55.

The pollutant setting the AQI on an ordinary day here:

ozone63%2,306 days
fine particles (PM2.5)37%1,332 days

Onondaga County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	358	298	56	4	0	36	125
2024	365	317	48	0	0	35	84
2023	361	273	80	8	4	40	258
2022	365	316	49	0	0	37	69
2021	365	279	85	1	0	39	113
2020	364	300	64	0	0	37	74
2019	365	301	64	0	0	39	77
2018	364	297	65	2	0	37	115
2017	365	310	55	0	0	36	93
2016	366	314	50	2	0	36	122
2015	364	273	91	0	0	37	93
2014	360	304	56	0	0	35	93
2013	349	311	38	0	0	34	93
2012	358	306	44	8	0	35	133
2011	365	318	45	2	0	34	119
2010	365	308	52	5	0	34	140

*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.