EnviroNearby

Orange County, North Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Orange, North Carolina, 1994–2008.

29%
Good days in 2006
55
Median daily AQI, 2006
0
Days above 100 in 2006
122
Days with an AQI in 2006 (of 365)

In 2006, EPA reported a daily Air Quality Index (AQI) for Orange, North Carolina on 122 days. 35 of those days (29%) were in the Good range, and the median daily AQI was 55. That median is higher than the typical monitored county in North Carolina (median 52 across 44 counties), and higher than the typical monitored U.S. county (44). The main pollutant was fine particles (PM2.5) on 122 days. Across the years with fuller monitoring, the share of Good days fell: an average of 95% in 1995–1997 versus 36% in 2000–2006.

EPA did not report an AQI for every day of 2006 here (122 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 2008; EPA's files for 2009–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (2001, 2002, 2003, 2005, 2007, 2008…) 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%1994: Good 49 of 65 days1994: Moderate 16 of 65 days19941995: Good 171 of 183 days1995: Moderate 12 of 183 days1996: Good 246 of 257 days1996: Moderate 11 of 257 days19961997: Good 174 of 183 days1997: Moderate 9 of 183 days1998: Good 156 of 156 days19981999: Good 153 of 230 days1999: Moderate 75 of 230 days1999: Unhealthy for Sensitive Groups 2 of 230 days2000: Good 88 of 179 days2000: Moderate 91 of 179 days20002001: Good 34 of 119 days2001: Moderate 84 of 119 days2001: Unhealthy for Sensitive Groups 1 of 119 days2002: Good 33 of 118 days2002: Moderate 85 of 118 days20022003: Good 38 of 114 days2003: Moderate 75 of 114 days2003: Unhealthy for Sensitive Groups 1 of 114 days2004: Good 35 of 120 days2004: Moderate 84 of 120 days2004: Unhealthy for Sensitive Groups 1 of 120 days20042005: Good 39 of 114 days2005: Moderate 75 of 114 days2006: Good 35 of 122 days2006: Moderate 87 of 122 days20062007: Good 45 of 119 days2007: Moderate 74 of 119 days2008: Good 29 of 90 days2008: Moderate 61 of 90 days2008
  • 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 year0501001994: 90th percentile AQI 571995: 90th percentile AQI 481996: 90th percentile AQI 421997: 90th percentile AQI 351998: 90th percentile AQI 341999: 90th percentile AQI 742000: 90th percentile AQI 732001: 90th percentile AQI 782002: 90th percentile AQI 732003: 90th percentile AQI 752004: 90th percentile AQI 772005: 90th percentile AQI 762006: 90th percentile AQI 762007: 90th percentile AQI 762008: 90th percentile AQI 721994: Median AQI 301995: Median AQI 241996: Median AQI 221997: Median AQI 191998: Median AQI 171999: Median AQI 342000: Median AQI 522001: Median AQI 562002: Median AQI 562003: Median AQI 552004: Median AQI 572005: Median AQI 572006: Median AQI 552007: Median AQI 552008: Median AQI 5519941996199820002002200420062008
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2006

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
Fine particles (PM2.5)122100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20089029610000557281PM2.5
200711945740000557697PM2.5
200612235870000557697PM2.5
200511439750000577698PM2.5
2004120358410005777104PM2.5
2003114387510005575111PM2.5
200211833850000567398PM2.5
2001119348410005678107PM2.5
200017988910000527390PM2.5
19992301537520003474109CO
199815615600000173449CO
199718317490000193590CO
1996257246110000224263CO
1995183171120000244878CO
19946549160000305767CO

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 North Carolina

Source: U.S. EPA AirData, “Annual AQI by County” files for 1994–2008 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem