Bad Air Days in Rockland County, New York: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 331 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (15% particle days).

When the bad days come in Rockland

Most bad days here fall in June 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.

Better or worse than it was

In 2000 to 2009 this county averaged 0 bad days a year; in 2016 to 2025, 3. It has got worse. The worst recent year was 2023, with 9 bad days on 363 monitored days.

Date	AQI	Main pollutant
2018-07-02	210	Ozone
2023-06-07	197	PM2.5
2023-06-06	163	PM2.5
2021-07-20	155	PM2.5
2023-06-30	151	Ozone

Most days, not the worst ones

Across 3,645 monitored days from 2016 to 2025, the air in Rockland County rated Good on 84% of them, more often than the 72% typical of monitored counties, and Moderate on 15%. The median day sat at AQI 38; one day in ten went above 55.

The pollutant setting the AQI on an ordinary day here:

ozone68%2,491 days
fine particles (PM2.5)32%1,154 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	312	46	7	0	37	136
2024	366	308	53	5	0	37	150
2023	363	288	66	9	3	38	197
2022	365	315	50	0	0	38	90
2021	362	314	47	1	1	37	155
2020	366	319	47	0	0	36	93
2019	365	314	50	1	0	39	112
2018	365	301	58	6	1	38	210
2017	365	309	55	1	0	38	105
2016	363	278	81	4	0	39	136
2015	365	249	111	5	0	42	143
2014	365	264	101	0	0	41	100
2013	365	242	120	3	0	43	143
2012	360	247	104	9	1	42	159
2011	340	215	116	9	0	44	122
2010	365	248	107	10	1	42	156

*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.