Bad Air Days in Windham County, Vermont

Not enough data

EPA monitors in Windham County ran on too few days between 2016 and 2025 to give a fair yearly count (about 30% of days covered). Neighbouring counties below are a better guide.

What to buy, and what not to

EPA monitors here ran too few days to give a fair yearly count. Use AirNow for today's air.

The record for Windham

The worst recent year was 2025, with 1 bad day on 100 monitored days.

Date	AQI	Main pollutant
2025-08-05	117	PM2.5
2023-07-17	95	PM2.5
2023-09-30	70	PM2.5
2024-08-16	69	PM2.5
2023-07-26	60	PM2.5

The air on a normal day

Across 1,088 monitored days from 2016 to 2025, the air in Windham County rated Good on 97% of them, more often than the 72% typical of monitored counties, and Moderate on 3%. The median day sat at AQI 13; one day in ten went above 33.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)100%1,088 days

Windham County by year

Year	Days monitored	Good	Moderate	Over 100	Median AQI	Highest AQI
2025*	100	92	7	1	15	117
2024	120	116	4	0	12	69
2023	119	112	7	0	14	95
2022	71	71	0	0	11	44
2021	118	114	4	0	11	56
2020	113	113	0	0	12	42
2019	104	103	1	0	11	52
2018	117	112	5	0	12	57
2017	118	115	3	0	14	54
2016	108	105	3	0	13	58
2015	112	105	7	0	18	66
2014	120	113	7	0	17	57
2013	118	113	5	0	16	58
2012	113	105	8	0	16	62
2011	5	5	0	0	9	14

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

Vermont compared

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.