Jasper County, Indiana air quality history

Daily Air Quality Index summaries from EPA monitors in Jasper, Indiana, 1980–2002.

66%

Good days in 1991

Median daily AQI, 1991

Days above 100 in 1991

173

Days with an AQI in 1991 (of 365)

In 1991, EPA reported a daily Air Quality Index (AQI) for Jasper, Indiana on 173 days. 115 of those days (66%) were in the Good range, and the median daily AQI was 42. That median is higher than the typical monitored county in Indiana (median 39 across 23 counties), and higher than the typical monitored U.S. county (39). The main pollutant was ozone on 136 days. Across the years with fuller monitoring, the share of Good days fell: an average of 98% in 1980–1982 versus 87% in 1984–1991.

EPA did not report an AQI for every day of 1991 here (173 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

The most recent year with data for this county is 2002; EPA's files for 2003–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1997, 1998, 1999, 2000, 2001, 2002…) 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, 1991

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	136	79%
Coarse particles (PM10)	37	21%

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
2002	61	61	0	0	0	14	26	47	PM10
2001	61	61	0	0	0	15	24	38	PM10
2000	62	62	0	0	0	17	26	40	PM10
1999	45	44	1	0	0	18	34	51	PM10
1998	60	59	1	0	0	19	34	91	PM10
1997	61	61	0	0	0	19	28	46	PM10
1996	65	65	0	0	0	19	30	46	PM10
1995	62	62	0	0	0	21	39	47	PM10
1994	56	55	1	0	0	21	39	54	PM10
1993	58	58	0	0	0	17	36	44	PM10
1992	55	54	1	0	0	17	26	89	PM10
1991	173	115	40	16	2	42	101	156	Ozone
1990	117	85	24	8	0	37	90	147	Ozone
1989	59	57	2	0	0	20	43	56	PM10
1988	46	41	5	0	0	20	51	62	PM10
1985	181	179	2	0	0	22	39	54	NO2
1984	365	347	17	1	0	23	42	105	NO2
1983	365	340	18	7	0	25	44	113	NO2
1982	334	322	12	0	0	21	37	74	NO2
1981	365	357	8	0	0	19	36	80	NO2
1980	360	355	5	0	0	21	37	62	NO2

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 1991

Switzerland

All monitored counties in Indiana

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2002 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem