Bad Air Days in Monroe County, Indiana: under 1 a Year

under 1 bad air day a year

Rare: among the cleanest-air counties EPA monitors. Ranked 806 of 996 monitored counties, where 1 is worst.

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

Which months to watch

Most bad days here fall in 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 0 bad days a year; in 2016 to 2025, under 1. Not much has changed. The worst recent year was 2023, with 5 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-06-28	230	PM2.5
2023-06-27	157	PM2.5
2023-07-16	119	PM2.5
2023-06-06	118	PM2.5
2023-06-29	114	PM2.5

Most days, not the worst ones

Across 3,516 monitored days from 2016 to 2025, the air in Monroe County rated Good on 71% of them, close to the 72% typical of monitored counties, and Moderate on 29%. The median day sat at AQI 39; one day in ten went above 57.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)100%3,516 days

Monroe County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	360	265	95	0	0	36	84
2024	359	290	69	0	0	34	63
2023	365	245	115	5	2	40	230
2022	347	265	82	0	0	38	96
2021	352	223	129	0	0	43	95
2020	357	240	117	0	0	41	72
2019	346	220	126	0	0	43	72
2018	335	182	153	0	0	48	98
2017	341	265	76	0	0	36	66
2016	354	295	59	0	0	34	66
2015	342	231	111	0	0	41	82
2014	346	210	135	1	1	44	159
2013	348	207	141	0	0	46	78
2012	356	225	131	0	0	43	88
2011	319	152	167	0	0	52	99
2010	302	99	203	0	0	56	89

*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.