EnviroNearby

Warren County, Virginia air quality history

Daily Air Quality Index summaries from EPA monitors in Warren, Virginia, 1983–2012.

56%
Good days in 1994
47
Median daily AQI, 1994
17
Days above 100 in 1994
211
Days with an AQI in 1994 (of 365)

In 1994, EPA reported a daily Air Quality Index (AQI) for Warren, Virginia on 211 days. 119 of those days (56%) were in the Good range, and the median daily AQI was 47. That median is about the same as the typical monitored county in Virginia (median 45 across 26 counties), and higher than the typical monitored U.S. county (39). The main pollutant was ozone on 181 days. Across the years with fuller monitoring, the share of Good days rose: an average of 54% in 1983–1985 versus 68% in 1992–1994.

EPA did not report an AQI for every day of 1994 here (211 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 2012; EPA's files for 2013–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (2007, 2008, 2009, 2010, 2011, 2012…) 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.

Share of monitored days in each AQI category, by year0%25%50%75%100%1983: Good 111 of 242 days1983: Moderate 73 of 242 days1983: Unhealthy for Sensitive Groups 44 of 242 days1983: Unhealthy 14 of 242 days19831984: Good 126 of 246 days1984: Moderate 75 of 246 days1984: Unhealthy for Sensitive Groups 36 of 246 days1984: Unhealthy 9 of 246 days1985: Good 120 of 184 days1985: Moderate 40 of 184 days1985: Unhealthy for Sensitive Groups 17 of 184 days1985: Unhealthy 7 of 184 days1986: Good 250 of 335 days1986: Moderate 67 of 335 days1986: Unhealthy for Sensitive Groups 17 of 335 days1986: Unhealthy 1 of 335 days1987: Good 202 of 344 days1987: Moderate 82 of 344 days1987: Unhealthy for Sensitive Groups 45 of 344 days1987: Unhealthy 15 of 344 days1988: Good 172 of 302 days1988: Moderate 65 of 302 days1988: Unhealthy for Sensitive Groups 35 of 302 days1988: Unhealthy 23 of 302 days1988: Very Unhealthy 7 of 302 days19881989: Good 247 of 339 days1989: Moderate 70 of 339 days1989: Unhealthy for Sensitive Groups 20 of 339 days1989: Unhealthy 2 of 339 days1990: Good 237 of 332 days1990: Moderate 72 of 332 days1990: Unhealthy for Sensitive Groups 22 of 332 days1990: Unhealthy 1 of 332 days1991: Good 213 of 315 days1991: Moderate 73 of 315 days1991: Unhealthy for Sensitive Groups 25 of 315 days1991: Unhealthy 4 of 315 days1992: Good 272 of 346 days1992: Moderate 66 of 346 days1992: Unhealthy for Sensitive Groups 7 of 346 days1992: Unhealthy 1 of 346 days1993: Good 167 of 246 days1993: Moderate 65 of 246 days1993: Unhealthy for Sensitive Groups 13 of 246 days1993: Unhealthy 1 of 246 days19931994: Good 119 of 211 days1994: Moderate 75 of 211 days1994: Unhealthy for Sensitive Groups 16 of 211 days1994: Unhealthy 1 of 211 days1995: Good 60 of 60 days1996: Good 59 of 59 days1997: Good 60 of 61 days1997: Moderate 1 of 61 days1998: Good 60 of 60 days19981999: Good 60 of 60 days2000: Good 58 of 58 days2001: Good 59 of 59 days2002: Good 60 of 60 days2003: Good 60 of 60 days20032004: Good 60 of 60 days2005: Good 59 of 59 days2006: Good 58 of 58 days2007: Good 58 of 58 days2008: Good 59 of 59 days20082009: Good 60 of 60 days2010: Good 59 of 59 days2011: Good 57 of 57 days2012: Good 60 of 60 days2012
  • 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 and 90th-percentile daily AQI, by year0501001501983: 90th percentile AQI 1431984: 90th percentile AQI 1261985: 90th percentile AQI 1191986: 90th percentile AQI 841987: 90th percentile AQI 1261988: 90th percentile AQI 1431989: 90th percentile AQI 931990: 90th percentile AQI 901991: 90th percentile AQI 971992: 90th percentile AQI 711993: 90th percentile AQI 841994: 90th percentile AQI 901995: 90th percentile AQI 371996: 90th percentile AQI 311997: 90th percentile AQI 301998: 90th percentile AQI 341999: 90th percentile AQI 312000: 90th percentile AQI 272001: 90th percentile AQI 312002: 90th percentile AQI 272003: 90th percentile AQI 232004: 90th percentile AQI 262005: 90th percentile AQI 272006: 90th percentile AQI 242007: 90th percentile AQI 282008: 90th percentile AQI 252009: 90th percentile AQI 192010: 90th percentile AQI 232011: 90th percentile AQI 192012: 90th percentile AQI 181983: Median AQI 581984: Median AQI 501985: Median AQI 431986: Median AQI 401987: Median AQI 451988: Median AQI 451989: Median AQI 411990: Median AQI 401991: Median AQI 421992: Median AQI 371993: Median AQI 441994: Median AQI 471995: Median AQI 191996: Median AQI 181997: Median AQI 181998: Median AQI 171999: Median AQI 182000: Median AQI 172001: Median AQI 132002: Median AQI 152003: Median AQI 142004: Median AQI 132005: Median AQI 162006: Median AQI 152007: Median AQI 172008: Median AQI 162009: Median AQI 142010: Median AQI 152011: Median AQI 122012: Median AQI 101983198819931998200320082012
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1994

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.

PollutantDays as main pollutantShare of monitored days
Ozone18186%
Coarse particles (PM10)3014%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2012606000000101822PM10
2011575700000121929PM10
2010595900000152339PM10
2009606000000141929PM10
2008595900000162535PM10
2007585800000172843PM10
2006585800000152433PM10
2005595900000162739PM10
2004606000000132641PM10
2003606000000142344PM10
2002606000000152740PM10
2001595900000133138PM10
2000585800000172742PM10
1999606000000183141PM10
1998606000000173445PM10
1997616010000183062PM10
1996595900000183136PM10
1995606000000193745PM10
199421111975161004790151Ozone
199324616765131004484151Ozone
19923462726671003771159Ozone
199131521373254004297177Ozone
199033223772221004090159Ozone
198933924770202004193172Ozone
19883021726535237045143237Ozone
19873442028245150045126190Ozone
198633525067171004084174Ozone
1985184120401770043119174Ozone
1984246126753690050126190Ozone
19832421117344140058143190Ozone

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.

Counties in Virginia with a similar median AQI in 1994

All monitored counties in Virginia

Source: U.S. EPA AirData, “Annual AQI by County” files for 1983–2012 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem