Chippewa County, Michigan air quality history

Daily Air Quality Index summaries from EPA monitors in Chippewa, Michigan, 2001–2019.

62%

Good days in 2018

Median daily AQI, 2018

Days above 100 in 2018

271

Days with an AQI in 2018 (of 365)

In 2018, EPA reported a daily Air Quality Index (AQI) for Chippewa, Michigan on 271 days. 167 of those days (62%) were in the Good range, and the median daily AQI was 43. That median is higher than the typical monitored county in Michigan (median 40 across 26 counties), and about the same as the typical monitored U.S. county (41). The main pollutant was fine particles (PM2.5) on 176 days. Across the years with fuller monitoring, the share of Good days rose: an average of 69% in 2002–2004 versus 75% in 2016–2018.

EPA did not report an AQI for every day of 2018 here (271 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 2019; EPA's files for 2020–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (2001, 2006, 2007, 2008, 2009, 2019) 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, 2018

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
Fine particles (PM2.5)	176	65%
Ozone	95	35%

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
2019	58	42	16	0	0	43	56	66	PM2.5
2018	271	167	104	0	0	43	59	73	PM2.5
2017	307	238	69	0	0	39	54	87	PM2.5
2016	299	258	40	1	0	37	53	101	PM2.5
2015	358	224	134	0	0	45	58	84	PM2.5
2014	324	261	63	0	0	37	56	77	PM2.5
2013	284	239	45	0	0	34	54	84	PM2.5
2012	270	198	63	9	0	38	63	147	PM2.5
2011	231	206	25	0	0	33	52	97	Ozone
2010	186	145	38	3	0	31	66	118	Ozone
2009	81	27	52	2	0	61	91	143	PM2.5
2008	96	38	56	2	0	54	82	138	PM2.5
2007	107	43	62	2	0	53	74	136	PM2.5
2006	97	65	30	2	0	37	63	132	PM2.5
2005	125	82	42	1	0	39	70	126	PM2.5
2004	124	95	29	0	0	33	63	94	PM2.5
2003	126	83	42	1	0	43	66	121	PM2.5
2002	121	78	42	0	1	38	61	152	PM2.5
2001	116	79	37	0	0	38	68	96	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.

All monitored counties in Michigan

Source: U.S. EPA AirData, “Annual AQI by County” files for 2001–2019 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem