Bad Air Days in Berkshire County, Massachusetts: 1 a Year

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 619 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (92% particle days).

When the bad days come in Berkshire

Most bad days here fall in June and July and August. 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 19 bad days a year; in 2016 to 2025, 1. The air has improved. The worst recent year was 2023, with 7 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-06-07	170	PM2.5
2023-06-08	163	PM2.5
2023-06-06	158	PM2.5
2023-07-01	149	PM2.5
2023-06-30	130	PM2.5

Most days, not the worst ones

Across 3,622 monitored days from 2016 to 2025, the air in Berkshire County rated Good on 71% of them, close to the 72% typical of monitored counties, and Moderate on 28%. The median day sat at AQI 41; one day in ten went above 59.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)66%2,393 days
ozone34%1,221 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	285	76	4	0	38	124
2024	366	300	66	0	0	38	97
2023	365	257	101	7	3	41	170
2022	365	269	96	0	0	42	87
2021	365	230	134	1	0	44	103
2020	366	278	88	0	0	40	94
2019	364	266	98	0	0	41	87
2018	365	232	132	1	0	42	122
2017	346	203	143	0	0	47	88
2016	355	259	96	0	0	36	82
2015	360	215	145	0	0	45	95
2014	364	164	200	0	0	52	93
2013	364	129	231	4	0	53	119
2012	348	166	175	7	0	51	112
2011	363	165	194	4	1	52	156
2010	348	224	116	8	0	41	133

*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.