Howard County, Indiana air quality history

Daily Air Quality Index summaries from EPA monitors in Howard, Indiana, 1999–2025.

67%

Good days in 2025

Median daily AQI, 2025

Days above 100 in 2025

362

Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Howard, Indiana on 362 days. 241 of those days (67%) were in the Good range, and the median daily AQI was 43. That median is about the same as the typical monitored county in Indiana (median 41 across 33 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 182 days. Across the years with fuller monitoring, the share of Good days rose: an average of 40% in 2014–2016 versus 66% in 2023–2025.

Years with fewer than 120 monitored days (2007, 2008, 2009, 2010, 2011, 2012…) are shown in the table but left out of comparisons and trend statements.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median daily AQI
90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

Pollutant	Days as main pollutant	Share of monitored days
Ozone	182	50%
Fine particles (PM2.5)	180	50%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
2025	362	241	118	3	0	43	61	122	Ozone
2024	366	241	125	0	0	44	61	93	Ozone
2023	365	234	119	10	2	45	67	199	Ozone
2022	364	246	114	4	0	44	63	108	Ozone
2021	361	227	132	2	0	44	62	105	PM2.5
2020	366	266	99	1	0	42	58	108	Ozone
2019	361	236	124	1	0	44	59	108	Ozone
2018	365	234	126	5	0	44	61	108	PM2.5
2017	356	211	145	0	0	45	58	83	PM2.5
2016	325	173	152	0	0	48	63	84	PM2.5
2015	346	101	244	1	0	58	71	101	PM2.5
2014	261	101	160	0	0	53	66	84	PM2.5
2012	11	6	5	0	0	44	61	62	PM2.5
2011	110	47	63	0	0	54	71	85	PM2.5
2010	112	44	67	1	0	53	81	113	PM2.5
2009	110	47	63	0	0	53	69	96	PM2.5
2008	102	42	60	0	0	54	72	100	PM2.5
2007	109	35	73	1	0	57	77	111	PM2.5
2006	114	41	73	0	0	56	75	91	PM2.5
2005	111	29	79	3	0	60	88	121	PM2.5
2004	114	35	79	0	0	57	73	99	PM2.5
2003	116	39	75	2	0	56	82	138	PM2.5
2002	119	29	88	2	0	59	81	111	PM2.5
2001	108	35	70	3	0	60	83	113	PM2.5
2000	112	23	88	1	0	63	83	101	PM2.5
1999	57	21	34	2	0	57	87	116	PM2.5

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Indiana with a similar median AQI in 2025

All monitored counties in Indiana

Source: U.S. EPA AirData, “Annual AQI by County” files for 1999–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem