Grand Forks County, North Dakota air quality history

Daily Air Quality Index summaries from EPA monitors in Grand Forks, North Dakota, 1985–2001.

67%

Good days in 2001

Median daily AQI, 2001

Days above 100 in 2001

120

Days with an AQI in 2001 (of 365)

In 2001, EPA reported a daily Air Quality Index (AQI) for Grand Forks, North Dakota on 120 days. 80 of those days (67%) were in the Good range, and the median daily AQI was 39. That median is higher than the typical monitored county in North Dakota (median 35 across 9 counties), and lower than the typical monitored U.S. county (44). The main pollutant was fine particles (PM2.5) on 120 days. Across the years with fuller monitoring, the share of Good days fell: an average of 97% in 1986–1991 versus 87% in 1992–2001.

EPA did not report an AQI for every day of 2001 here (120 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 2001; EPA's files for 2002–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1995, 1996, 1997, 1998, 1999, 2000…) 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, 2001

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)	120	100%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Median AQI	90th pct.	Max AQI	Main pollutant
2001	120	80	40	0	39	62	99	PM2.5
2000	113	81	32	0	35	63	86	PM2.5
1999	93	54	39	0	45	64	90	PM2.5
1998	55	49	6	0	20	51	64	PM10
1997	54	50	4	0	16	41	64	PM10
1996	59	58	1	0	14	33	71	PM10
1995	61	61	0	0	14	28	46	PM10
1994	82	80	2	0	15	29	59	PM10
1993	193	192	1	0	19	35	66	NO2
1992	174	166	7	1	19	36	106	NO2
1991	196	190	6	0	19	37	80	NO2
1990	178	172	6	0	19	35	97	NO2
1989	34	34	0	0	19	44	49	PM10
1987	35	35	0	0	21	30	49	PM10
1986	175	170	5	0	19	33	85	PM10
1985	35	35	0	0	24	41	47	PM10

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 North Dakota

Source: U.S. EPA AirData, “Annual AQI by County” files for 1985–2001 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem