Bad Air Days in Greene County, Missouri: 1 a Year

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 659 of 996 monitored counties, where 1 is worst.

What makes them bad: a mix of particles and ozone (55% particle days).

The bad-air season here

Most bad days here fall in June and March. 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 8 bad days a year; in 2016 to 2025, 1. The air has improved. The worst recent year was 2023, with 6 bad days on 365 monitored days.

Date	AQI	Main pollutant
2025-03-15	160	PM10
2023-05-25	122	Ozone
2025-03-14	118	PM10
2020-06-27	116	PM2.5
2025-08-01	109	PM2.5

The air on a normal day

Across 3,650 monitored days from 2016 to 2025, the air in Greene County rated Good on 66% of them, less often than the 72% typical of monitored counties, and Moderate on 33%. The median day sat at AQI 44; one day in ten went above 60.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)60%2,172 days
ozone38%1,392 days
coarse dust (PM10)2%86 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	364	228	132	4	1	45	160
2024	366	232	134	0	0	45	90
2023	365	188	171	6	0	49	122
2022	365	202	163	0	0	49	100
2021	365	300	65	0	0	38	84
2020	364	268	95	1	0	40	116
2019	365	262	103	0	0	43	77
2018	365	242	123	0	0	44	93
2017	365	243	122	0	0	44	80
2016	366	262	104	0	0	42	71
2015	358	234	124	0	0	43	80
2014	365	208	157	0	0	46	87
2013	360	218	142	0	0	46	97
2012	366	138	208	20	0	55	150
2011	322	147	167	8	0	53	143
2010	325	213	111	1	0	44	101

*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, and on why a purifier does not touch ozone in smoke vs ozone.