Smyth County, Virginia air quality history

Daily Air Quality Index summaries from EPA monitors in Smyth, Virginia, 1980–1997.

64%

Good days in 1989

Median daily AQI, 1989

Days above 100 in 1989

213

Days with an AQI in 1989 (of 365)

In 1989, EPA reported a daily Air Quality Index (AQI) for Smyth, Virginia on 213 days. 137 of those days (64%) were in the Good range, and the median daily AQI was 45. That median is higher than the typical monitored county in Virginia (median 41 across 21 counties), and higher than the typical monitored U.S. county (39). The main pollutant was ozone on 213 days. Across the years with fuller monitoring, the share of Good days rose: an average of 49% in 1980–1982 versus 55% in 1987–1989.

EPA did not report an AQI for every day of 1989 here (213 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 1997; EPA's files for 1998–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1992, 1993, 1994, 1995, 1996, 1997…) 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, 1989

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	213	100%

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
1997	61	60	1	0	0	0	14	32	56	PM10
1996	61	60	1	0	0	0	18	31	63	PM10
1995	60	58	2	0	0	0	19	33	57	PM10
1994	61	61	0	0	0	0	19	30	44	PM10
1993	61	59	2	0	0	0	19	37	52	PM10
1992	61	59	2	0	0	0	19	35	57	PM10
1991	56	54	2	0	0	0	22	37	69	PM10
1990	60	58	2	0	0	0	24	41	53	PM10
1989	213	137	69	7	0	0	45	87	150	Ozone
1988	213	103	73	26	10	1	51	126	207	Ozone
1987	207	111	73	21	2	0	48	101	154	Ozone
1986	169	100	57	11	1	0	46	93	151	Ozone
1985	178	85	72	21	0	0	51	105	143	Ozone
1984	176	103	55	17	1	0	48	101	154	Ozone
1983	172	62	79	27	4	0	58	122	166	Ozone
1982	161	85	62	11	3	0	49	93	161	Ozone
1981	181	93	73	15	0	0	49	100	136	Ozone
1980	179	78	75	22	4	0	58	108	161	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 1980–1997 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem