Giles County, Tennessee air quality history

Daily Air Quality Index summaries from EPA monitors in Giles, Tennessee, 1980–1997.

47%

Good days in 1996

Median daily AQI, 1996

Days above 100 in 1996

212

Days with an AQI in 1996 (of 366)

In 1996, EPA reported a daily Air Quality Index (AQI) for Giles, Tennessee on 212 days. 99 of those days (47%) were in the Good range, and the median daily AQI was 51. That median is higher than the typical monitored county in Tennessee (median 44.5 across 22 counties), and higher than the typical monitored U.S. county (39). The main pollutant was ozone on 206 days. Across the years with fuller monitoring, the share of Good days fell: an average of 71% in 1980–1982 versus 50% in 1987–1996.

EPA did not report an AQI for every day of 1996 here (212 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 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 (1993, 1994, 1995, 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, 1996

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	206	97%
Coarse particles (PM10)	6	3%

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	11	11	0	0	0	0	14	19	20	PM10
1996	212	99	87	24	2	0	51	105	197	Ozone
1995	4	4	0	0	0	0	21	21	21	PM10
1994	40	40	0	0	0	0	18	29	46	PM10
1993	48	47	1	0	0	0	19	37	51	PM10
1988	181	84	56	24	17	0	54	150	200	Ozone
1987	176	102	56	17	1	0	48	101	166	Ozone
1986	201	108	70	22	1	0	48	105	154	Ozone
1985	206	147	54	5	0	0	44	80	122	Ozone
1984	215	125	63	26	1	0	47	101	154	Ozone
1983	333	220	80	28	5	0	44	100	190	Ozone
1982	348	223	85	37	3	0	42	101	182	Ozone
1981	343	286	48	9	0	0	34	61	143	Ozone
1980	359	231	78	31	18	1	43	119	214	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 Tennessee

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