Bad Air Days in West Baton Rouge Parish, Louisiana: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 365 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (10% particle days).

When the bad days come in West Baton Rouge

Most bad days here fall in May and June and September and August. 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 worst days on file

In 2000 to 2009 this county averaged 18 bad days a year; in 2016 to 2025, 3. The air has improved. The worst recent year was 2023, with 9 bad days on 362 monitored days.

Date	AQI	Main pollutant
2021-10-09	150	Ozone
2017-09-14	140	Ozone
2023-09-20	140	Ozone
2023-05-28	136	Ozone
2018-05-09	129	Ozone

Most days, not the worst ones

Across 3,648 monitored days from 2016 to 2025, the air in West Baton Rouge Parish rated Good on 56% of them, less often than the 72% typical of monitored counties, and Moderate on 44%. The median day sat at AQI 48; one day in ten went above 63.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)73%2,671 days
ozone26%949 days
nitrogen dioxide1%28 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	180	183	2	0	51	122
2024	366	198	166	2	0	49	101
2023	362	154	199	9	0	52	140
2022	364	216	144	4	0	46	105
2021	365	220	142	3	0	46	150
2020	366	229	134	3	0	44	101
2019	364	202	162	0	0	47	100
2018	365	218	144	3	0	46	129
2017	365	199	163	3	0	48	140
2016	366	213	151	2	0	47	112
2015	365	215	147	3	0	46	143
2014	365	169	195	1	0	52	112
2013	365	194	170	1	0	49	101
2012	366	132	232	2	1	54	159
2011	365	68	286	11	1	59	192
2010	365	95	266	4	0	59	115

*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.