Saginaw County, Michigan air quality history

Daily Air Quality Index summaries from EPA monitors in Saginaw, Michigan, 1980–2005.

91%

Good days in 1992

Median daily AQI, 1992

Days above 100 in 1992

176

Days with an AQI in 1992 (of 366)

In 1992, EPA reported a daily Air Quality Index (AQI) for Saginaw, Michigan on 176 days. 161 of those days (91%) were in the Good range, and the median daily AQI was 21. That median is lower than the typical monitored county in Michigan (median 32 across 21 counties), and lower than the typical monitored U.S. county (37). The main pollutant was coarse particles (PM10) on 176 days. Across the years with fuller monitoring, the share of Good days rose: an average of 85% in 1980–1982 versus 93% in 1990–1992.

EPA did not report an AQI for every day of 1992 here (176 of 366 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 2005; EPA's files for 2006–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (2000, 2001, 2002, 2003, 2004, 2005…) 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, 1992

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
Coarse particles (PM10)	176	100%

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
2005	114	58	52	4	0	50	77	125	PM2.5
2004	118	73	45	0	0	38	79	94	PM2.5
2003	113	56	57	0	0	51	72	96	PM2.5
2002	106	51	55	0	0	52	70	94	PM2.5
2001	118	60	56	2	0	50	80	119	PM2.5
2000	107	61	46	0	0	45	71	94	PM2.5
1999	89	51	37	1	0	41	75	101	PM2.5
1995	20	20	0	0	0	9	24	31	PM10
1994	59	59	0	0	0	18	38	44	PM10
1993	61	60	1	0	0	17	34	51	PM10
1992	176	161	15	0	0	21	47	96	PM10
1991	358	325	33	0	0	25	48	72	PM10
1990	365	349	16	0	0	19	40	61	PM10
1989	365	335	30	0	0	20	48	94	PM10
1988	366	337	29	0	0	18	47	82	PM10
1987	352	333	18	1	0	9	36	104	CO
1986	365	355	9	1	0	8	25	113	CO
1985	365	345	18	2	0	11	39	135	CO
1984	366	360	6	0	0	11	24	79	CO
1983	353	350	3	0	0	14	27	68	CO
1982	365	351	14	0	0	20	39	68	CO
1981	365	326	35	4	0	25	53	119	CO
1980	366	259	96	10	1	40	74	177	Ozone

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.

All monitored counties in Michigan

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2005 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem