Bad Air Days in Greene County, Indiana: 2 a Year

2 bad air days a year

About the middle of monitored US counties. Ranked 484 of 996 monitored counties, where 1 is worst.

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

Which months to watch

Most bad days here fall in June and May. 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.

The record for Greene

The worst recent year was 2023, with 11 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-06-28	217	PM2.5
2023-06-27	154	PM2.5
2023-06-06	147	Ozone
2016-06-10	140	Ozone
2016-06-11	129	Ozone

An ordinary day in Greene

Across 3,402 monitored days from 2016 to 2025, the air in Greene County rated Good on 77% of them, more often than the 72% typical of monitored counties, and Moderate on 22%. The median day sat at AQI 40; one day in ten went above 58.

The pollutant setting the AQI on an ordinary day here:

ozone71%2,427 days
fine particles (PM2.5)29%975 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	263	102	0	0	42	90
2024	362	266	96	0	0	42	97
2023	365	234	120	11	2	44	217
2022	351	298	51	2	0	38	101
2021	356	288	68	0	0	38	100
2020	361	312	49	0	0	36	90
2019	355	291	64	0	0	40	87
2018	361	294	64	3	0	38	129
2017	282	213	68	1	0	43	101
2016	244	161	80	3	0	42	140
2015	243	168	73	2	0	44	115
2014	244	166	78	0	0	45	88
2013	242	152	89	1	0	46	122
2012	241	109	113	19	1	52	151
2011	153	96	48	9	1	48	159
2010	166	104	56	6	0	47	119

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

Elsewhere in Indiana

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.