Bad Air Days in Howard County, Indiana: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 395 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (25% particle days).

When the bad days come in Howard

Most bad days here fall in June and July and May. 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.

Better or worse than it was

The worst recent year was 2023, with 12 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-06-28	199	PM2.5
2023-06-27	195	PM2.5
2023-06-29	135	PM2.5
2023-07-17	135	PM2.5
2023-06-02	126	Ozone

The air on a normal day

Across 3,591 monitored days from 2016 to 2025, the air in Howard County rated Good on 64% of them, less often than the 72% typical of monitored counties, and Moderate on 35%. The median day sat at AQI 44; one day in ten went above 61.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)59%2,115 days
ozone41%1,476 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	362	241	118	3	0	43	122
2024	366	241	125	0	0	44	93
2023	365	234	119	12	2	45	199
2022	364	246	114	4	0	44	108
2021	361	227	132	2	0	44	105
2020	366	266	99	1	0	42	108
2019	361	236	124	1	0	44	108
2018	365	234	126	5	0	44	108
2017	356	211	145	0	0	45	83
2016	325	173	152	0	0	48	84
2015	346	101	244	1	0	58	101
2014	261	101	160	0	0	53	84
2012	11	6	5	0	0	44	62
2011	110	47	63	0	0	54	85
2010	112	44	67	1	0	53	113

*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.