Fairfax City, Virginia air quality history

Daily Air Quality Index summaries from EPA monitors in Fairfax City, Virginia, 1980–1993.

93%

Good days in 1992

Median daily AQI, 1992

Days above 100 in 1992

123

Days with an AQI in 1992 (of 366)

In 1992, EPA reported a daily Air Quality Index (AQI) for Fairfax City, Virginia on 123 days. 115 of those days (93%) were in the Good range, and the median daily AQI was 33. That median is lower than the typical monitored county in Virginia (median 42 across 24 counties), and lower than the typical monitored U.S. county (37). The main pollutant was nitrogen dioxide (NO₂) on 63 days. Across the years with fuller monitoring, the share of Good days rose: an average of 71% in 1980–1982 versus 77% in 1990–1992.

EPA did not report an AQI for every day of 1992 here (123 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 1993; EPA's files for 1994–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1993) 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
Nitrogen dioxide (NO₂)	63	51%
Coarse particles (PM10)	46	37%
Ozone	14	11%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Very Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
1993	31	30	1	0	0	0	20	34	55	PM10
1992	123	115	8	0	0	0	33	47	67	NO2
1991	365	240	83	31	9	2	42	105	205	Ozone
1990	365	262	80	16	7	0	41	80	200	NO2
1989	365	256	86	18	4	1	43	86	202	NO2
1988	366	227	81	25	17	16	45	140	241	NO2
1987	365	187	129	27	19	3	50	126	212	NO2
1986	365	217	108	28	12	0	46	108	200	NO2
1985	365	217	107	28	12	1	46	105	203	Ozone
1984	359	216	120	21	1	1	47	84	218	NO2
1983	365	237	76	35	14	3	41	115	221	Ozone
1982	365	237	91	23	11	3	42	101	218	Ozone
1981	365	256	84	19	6	0	40	87	174	Ozone
1980	366	289	44	21	8	4	36	93	218	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 Virginia

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–1993 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem