Bad Air Days in Sainte Genevieve County, Missouri: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 409 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (0% particle days).

Which months to watch

Most bad days here fall in June. Averaged over 2016 to 2025.

What actually helps 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 Sainte Genevieve

In 2000 to 2009 this county averaged 19 bad days a year; in 2016 to 2025, 3. The air has improved. The worst recent year was 2023, with 12 bad days on 245 monitored days.

Date	AQI	Main pollutant
2023-06-06	147	Ozone
2023-06-03	140	Ozone
2023-06-09	140	Ozone
2023-06-23	126	Ozone
2023-06-04	122	Ozone

An ordinary day in Sainte Genevieve

Across 2,434 monitored days from 2016 to 2025, the air in Sainte Genevieve County rated Good on 89% of them, more often than the 72% typical of monitored counties, and Moderate on 11%. The median day sat at AQI 41; one day in ten went above 54.

The pollutant setting the AQI on an ordinary day here:

ozone100%2,434 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	255	233	20	2	0	41	108
2024	252	229	23	0	0	43	100
2023	245	195	38	12	0	44	147
2022	244	215	29	0	0	41	100
2021	245	227	18	0	0	39	100
2020	245	229	16	0	0	36	87
2019	244	229	15	0	0	38	87
2018	245	210	35	0	0	40	97
2017	245	204	39	2	0	44	101
2016	214	185	27	2	0	39	105
2015	220	190	30	0	0	39	93
2014	262	165	93	4	0	45	115
2013	263	176	86	1	0	44	105
2012	251	151	84	16	2	47	177
2011	251	153	96	2	0	46	122
2010	309	207	94	8	0	43	129

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

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