EnviroNearby

Northampton County, Virginia air quality history

Daily Air Quality Index summaries from EPA monitors in Northampton, Virginia, 1980–1990.

61%
Good days in 1990
45
Median daily AQI, 1990
24
Days above 100 in 1990
214
Days with an AQI in 1990 (of 365)

In 1990, EPA reported a daily Air Quality Index (AQI) for Northampton, Virginia on 214 days. 131 of those days (61%) were in the Good range, and the median daily AQI was 45. That median is higher than the typical monitored county in Virginia (median 42 across 24 counties), and higher than the typical monitored U.S. county (39). The main pollutant was ozone on 214 days. Across the years with fuller monitoring, the share of Good days rose: an average of 40% in 1980–1982 versus 59% in 1988–1990.

EPA did not report an AQI for every day of 1990 here (214 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 1990; EPA's files for 1991–2025 contain no row for it, which usually means its monitors stopped reporting.

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%1980: Good 60 of 177 days1980: Moderate 68 of 177 days1980: Unhealthy for Sensitive Groups 34 of 177 days1980: Unhealthy 14 of 177 days1980: Very Unhealthy 1 of 177 days19801981: Good 76 of 167 days1981: Moderate 51 of 167 days1981: Unhealthy for Sensitive Groups 29 of 167 days1981: Unhealthy 10 of 167 days1981: Very Unhealthy 1 of 167 days19811982: Good 65 of 159 days1982: Moderate 60 of 159 days1982: Unhealthy for Sensitive Groups 25 of 159 days1982: Unhealthy 8 of 159 days1982: Very Unhealthy 1 of 159 days19821983: Good 42 of 136 days1983: Moderate 36 of 136 days1983: Unhealthy for Sensitive Groups 34 of 136 days1983: Unhealthy 18 of 136 days1983: Very Unhealthy 6 of 136 days19831984: Good 83 of 164 days1984: Moderate 55 of 164 days1984: Unhealthy for Sensitive Groups 16 of 164 days1984: Unhealthy 10 of 164 days19841985: Good 93 of 209 days1985: Moderate 74 of 209 days1985: Unhealthy for Sensitive Groups 33 of 209 days1985: Unhealthy 9 of 209 days19851986: Good 91 of 184 days1986: Moderate 54 of 184 days1986: Unhealthy for Sensitive Groups 30 of 184 days1986: Unhealthy 9 of 184 days19861987: Good 107 of 212 days1987: Moderate 53 of 212 days1987: Unhealthy for Sensitive Groups 34 of 212 days1987: Unhealthy 18 of 212 days19871988: Good 122 of 210 days1988: Moderate 59 of 210 days1988: Unhealthy for Sensitive Groups 16 of 210 days1988: Unhealthy 12 of 210 days1988: Very Unhealthy 1 of 210 days19881989: Good 118 of 209 days1989: Moderate 68 of 209 days1989: Unhealthy for Sensitive Groups 20 of 209 days1989: Unhealthy 3 of 209 days19891990: Good 131 of 214 days1990: Moderate 59 of 214 days1990: Unhealthy for Sensitive Groups 18 of 214 days1990: Unhealthy 5 of 214 days1990: Very Unhealthy 1 of 214 days1990
  • 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 year0501001502001980: 90th percentile AQI 1361981: 90th percentile AQI 1361982: 90th percentile AQI 1291983: 90th percentile AQI 1741984: 90th percentile AQI 1191985: 90th percentile AQI 1261986: 90th percentile AQI 1261987: 90th percentile AQI 1471988: 90th percentile AQI 1121989: 90th percentile AQI 1051990: 90th percentile AQI 1051980: Median AQI 711981: Median AQI 541982: Median AQI 581983: Median AQI 871984: Median AQI 501985: Median AQI 581986: Median AQI 511987: Median AQI 501988: Median AQI 471989: Median AQI 471990: Median AQI 4519801981198219831984198519861987198819891990
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1990

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
Ozone214100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
1990214131591851045105207Ozone
1989209118682030047105159Ozone
19882101225916121047112203Ozone
19872121075334180050147197Ozone
198618491543090051126182Ozone
198520993743390058126200Ozone
1984164835516100050119177Ozone
1983136423634186087174216Ozone
198215965602581058129203Ozone
1981167765129101054136214Ozone
1980177606834141071136202Ozone

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 1980–1990 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem