EnviroNearby

Sebastian County, Arkansas air quality history

Daily Air Quality Index summaries from EPA monitors in Sebastian, Arkansas, 1989–2011.

100%
Good days in 1992
21
Median daily AQI, 1992
0
Days above 100 in 1992
288
Days with an AQI in 1992 (of 366)

In 1992, EPA reported a daily Air Quality Index (AQI) for Sebastian, Arkansas on 288 days. 287 of those days (100%) were in the Good range, and the median daily AQI was 21. That median is lower than the typical monitored county in Arkansas (median 33 across 7 counties), and lower than the typical monitored U.S. county (37). The main pollutant was nitrogen dioxide (NO₂) on 248 days.

EPA did not report an AQI for every day of 1992 here (288 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 2011; EPA's files for 2012–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (2006, 2007, 2008, 2009, 2010, 2011…) 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%1989: Good 39 of 40 days1989: Moderate 1 of 40 days19891990: Good 55 of 57 days1990: Moderate 2 of 57 days1991: Good 132 of 133 days1991: Moderate 1 of 133 days19911992: Good 287 of 288 days1992: Moderate 1 of 288 days1993: Good 58 of 60 days1993: Moderate 2 of 60 days19931994: Good 56 of 56 days1995: Good 56 of 58 days1995: Moderate 2 of 58 days19951996: Good 59 of 60 days1996: Moderate 1 of 60 days1997: Good 57 of 59 days1997: Moderate 2 of 59 days19971999: Good 12 of 55 days1999: Moderate 43 of 55 days2000: Good 23 of 115 days2000: Moderate 92 of 115 days20002001: Good 26 of 106 days2001: Moderate 80 of 106 days2002: Good 43 of 112 days2002: Moderate 69 of 112 days20022003: Good 35 of 109 days2003: Moderate 74 of 109 days2004: Good 40 of 110 days2004: Moderate 70 of 110 days20042005: Good 29 of 85 days2005: Moderate 54 of 85 days2005: Unhealthy for Sensitive Groups 2 of 85 days2006: Good 44 of 115 days2006: Moderate 71 of 115 days20062007: Good 34 of 117 days2007: Moderate 83 of 117 days2008: Good 47 of 114 days2008: Moderate 67 of 114 days20082009: Good 45 of 113 days2009: Moderate 68 of 113 days2010: Good 35 of 110 days2010: Moderate 75 of 110 days20102011: Good 5 of 17 days2011: Moderate 12 of 17 days2011
  • 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 year0501001989: 90th percentile AQI 431990: 90th percentile AQI 351991: 90th percentile AQI 331992: 90th percentile AQI 341993: 90th percentile AQI 371994: 90th percentile AQI 351995: 90th percentile AQI 411996: 90th percentile AQI 341997: 90th percentile AQI 361999: 90th percentile AQI 732000: 90th percentile AQI 732001: 90th percentile AQI 762002: 90th percentile AQI 692003: 90th percentile AQI 682004: 90th percentile AQI 712005: 90th percentile AQI 912006: 90th percentile AQI 682007: 90th percentile AQI 712008: 90th percentile AQI 702009: 90th percentile AQI 652010: 90th percentile AQI 682011: 90th percentile AQI 731989: Median AQI 241990: Median AQI 211991: Median AQI 231992: Median AQI 211993: Median AQI 201994: Median AQI 201995: Median AQI 241996: Median AQI 241997: Median AQI 191999: Median AQI 592000: Median AQI 582001: Median AQI 582002: Median AQI 562003: Median AQI 542004: Median AQI 562005: Median AQI 592006: Median AQI 542007: Median AQI 542008: Median AQI 522009: Median AQI 532010: Median AQI 552011: Median AQI 56198919911993199519972000200220042006200820102011
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1992

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
Nitrogen dioxide (NO₂)24886%
Coarse particles (PM10)4014%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2011175120000567377PM2.5
201011035750000556886PM2.5
200911345680000536584PM2.5
200811447670000527077PM2.5
200711734830000547198PM2.5
200611544710000546886PM2.5
200585295420005991107PM2.5
200411040700000567192PM2.5
200310935740000546889PM2.5
200211243690000566987PM2.5
200110626800000587690PM2.5
200011523920000587392PM2.5
19995512430000597386PM2.5
1997595720000193657PM10
1996605910000243457PM10
1995585620000244152PM10
1994565600000203544PM10
1993605820000203754PM10
199228828710000213454NO2
199113313210000233354NO2
1990575520000213556PM10
1989403910000244352PM10

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 Arkansas with a similar median AQI in 1992

All monitored counties in Arkansas

Source: U.S. EPA AirData, “Annual AQI by County” files for 1989–2011 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem