EnviroNearby

Elbert County, Colorado air quality history

Daily Air Quality Index summaries from EPA monitors in Elbert, Colorado, 1999–2011.

94%
Good days in 2001
22
Median daily AQI, 2001
0
Days above 100 in 2001
122
Days with an AQI in 2001 (of 365)

In 2001, EPA reported a daily Air Quality Index (AQI) for Elbert, Colorado on 122 days. 115 of those days (94%) were in the Good range, and the median daily AQI was 22. That median is lower than the typical monitored county in Colorado (median 42 across 23 counties), and lower than the typical monitored U.S. county (44). The main pollutant was fine particles (PM2.5) on 122 days.

EPA did not report an AQI for every day of 2001 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 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%1999: Good 66 of 67 days1999: Moderate 1 of 67 days19992000: Good 108 of 113 days2000: Moderate 5 of 113 days20002001: Good 115 of 122 days2001: Moderate 7 of 122 days20012002: Good 109 of 118 days2002: Moderate 9 of 118 days20022003: Good 114 of 118 days2003: Moderate 4 of 118 days20032004: Good 110 of 111 days2004: Moderate 1 of 111 days20042005: Good 82 of 88 days2005: Moderate 6 of 88 days20052006: Good 49 of 51 days2006: Moderate 2 of 51 days20062007: Good 48 of 52 days2007: Moderate 4 of 52 days20072008: Good 55 of 60 days2008: Moderate 5 of 60 days20082009: Good 53 of 55 days2009: Moderate 2 of 55 days20092010: Good 57 of 59 days2010: Moderate 2 of 59 days20102011: Good 15 of 15 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 year0501001999: 90th percentile AQI 322000: 90th percentile AQI 392001: 90th percentile AQI 442002: 90th percentile AQI 472003: 90th percentile AQI 412004: 90th percentile AQI 342005: 90th percentile AQI 442006: 90th percentile AQI 352007: 90th percentile AQI 482008: 90th percentile AQI 462009: 90th percentile AQI 362010: 90th percentile AQI 392011: 90th percentile AQI 391999: Median AQI 212000: Median AQI 212001: Median AQI 222002: Median AQI 232003: Median AQI 222004: Median AQI 222005: Median AQI 262006: Median AQI 202007: Median AQI 262008: Median AQI 232009: Median AQI 202010: Median AQI 232011: Median AQI 141999200020012002200320042005200620072008200920102011
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2001

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
2011151500000143943PM2.5
2010595720000233959PM2.5
2009555320000203654PM2.5
2008605550000234654PM2.5
2007524840000264857PM2.5
2006514920000203572PM2.5
2005888260000264461PM2.5
200411111010000223457PM2.5
200311811440000224155PM2.5
200211810990000234760PM2.5
200112211570000224456PM2.5
200011310850000213957PM2.5
1999676610000213255PM2.5

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 Colorado

Source: U.S. EPA AirData, “Annual AQI by County” files for 1999–2011 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem