EnviroNearby

Onslow County, North Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Onslow, North Carolina, 1990–2007.

57%
Good days in 2007
47
Median daily AQI, 2007
0
Days above 100 in 2007
120
Days with an AQI in 2007 (of 365)

In 2007, EPA reported a daily Air Quality Index (AQI) for Onslow, North Carolina on 120 days. 69 of those days (57%) were in the Good range, and the median daily AQI was 47. That median is lower than the typical monitored county in North Carolina (median 57 across 41 counties), and about the same as the typical monitored U.S. county (46). The main pollutant was fine particles (PM2.5) on 113 days.

EPA did not report an AQI for every day of 2007 here (120 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 2007; EPA's files for 2008–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1997, 1998, 1999, 2001, 2003, 2004…) 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%1990: Good 19 of 20 days1990: Moderate 1 of 20 days19901991: Good 60 of 60 days1992: Good 59 of 60 days1992: Moderate 1 of 60 days19921993: Good 58 of 58 days1994: Good 53 of 54 days1994: Moderate 1 of 54 days19941995: Good 56 of 56 days1996: Good 60 of 60 days19961997: Good 59 of 59 days1998: Good 56 of 56 days19981999: Good 47 of 117 days1999: Moderate 67 of 117 days1999: Unhealthy for Sensitive Groups 3 of 117 days2000: Good 39 of 120 days2000: Moderate 81 of 120 days20002001: Good 52 of 118 days2001: Moderate 65 of 118 days2001: Unhealthy for Sensitive Groups 1 of 118 days2002: Good 45 of 120 days2002: Moderate 75 of 120 days20022003: Good 44 of 119 days2003: Moderate 75 of 119 days2004: Good 49 of 117 days2004: Moderate 68 of 117 days20042005: Good 53 of 120 days2005: Moderate 66 of 120 days2005: Unhealthy for Sensitive Groups 1 of 120 days2006: Good 57 of 121 days2006: Moderate 64 of 121 days20062007: Good 69 of 120 days2007: Moderate 51 of 120 days2007
  • 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 year0501001990: 90th percentile AQI 441991: 90th percentile AQI 361992: 90th percentile AQI 331993: 90th percentile AQI 321994: 90th percentile AQI 261995: 90th percentile AQI 271996: 90th percentile AQI 311997: 90th percentile AQI 301998: 90th percentile AQI 341999: 90th percentile AQI 752000: 90th percentile AQI 702001: 90th percentile AQI 702002: 90th percentile AQI 682003: 90th percentile AQI 672004: 90th percentile AQI 712005: 90th percentile AQI 722006: 90th percentile AQI 682007: 90th percentile AQI 651990: Median AQI 231991: Median AQI 211992: Median AQI 191993: Median AQI 211994: Median AQI 191995: Median AQI 181996: Median AQI 191997: Median AQI 171998: Median AQI 191999: Median AQI 552000: Median AQI 562001: Median AQI 522002: Median AQI 522003: Median AQI 532004: Median AQI 542005: Median AQI 532006: Median AQI 522007: Median AQI 471990199219941996199820002002200420062007
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2007

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)11394%
Coarse particles (PM10)76%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
200712069510000476599PM2.5
200612157640000526887PM2.5
2005120536610005372117PM2.5
200411749680000547184PM2.5
200311944750000536799PM2.5
200212045750000526888PM2.5
2001118526510005270108PM2.5
200012039810000567098PM2.5
1999117476730005575115PM2.5
1998565600000193440PM10
1997595900000173048PM10
1996606000000193141PM10
1995565600000182740PM10
1994545310000192657PM10
1993585800000213247PM10
1992605910000193358PM10
1991606000000213642PM10
1990201910000234451PM10

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 1990–2007 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem