Bad Air Days in Montgomery County, North Carolina: under 1 a Year

under 1 bad air days a year

Rare: among the cleanest-air counties EPA monitors. Ranked 902 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (100% particle days).

The bad-air season here

Most bad days here fall in February and June and July. 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 12 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2023, with 3 bad days on 363 monitored days.

Date	AQI	Main pollutant
2023-02-28	134	PM2.5
2023-07-18	131	PM2.5
2023-06-29	118	PM2.5
2023-07-17	100	PM2.5
2023-06-07	99	PM2.5

An ordinary day in Montgomery

Across 3,644 monitored days from 2016 to 2025, the air in Montgomery County rated Good on 74% of them, close to the 72% typical of monitored counties, and Moderate on 26%. The median day sat at AQI 42; one day in ten went above 56.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)55%2,000 days
ozone45%1,644 days

Montgomery County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	363	297	66	0	0	39	85
2024	366	257	109	0	0	42	83
2023	363	200	160	3	0	48	134
2022	363	263	100	0	0	43	80
2021	365	257	108	0	0	43	80
2020	366	281	85	0	0	40	85
2019	365	256	109	0	0	44	71
2018	363	282	81	0	0	39	98
2017	365	307	58	0	0	41	71
2016	365	288	77	0	0	41	87
2015	362	235	127	0	0	45	80
2014	365	184	181	0	0	50	84
2013	361	274	87	0	0	42	80
2012	361	294	65	2	1	40	151
2011	342	230	111	1	0	43	112
2010	331	221	106	4	0	43	129

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

Elsewhere in North Carolina

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.