Walker County, Alabama air quality history

Daily Air Quality Index summaries from EPA monitors in Walker, Alabama, 1990–2011.

35%

Good days in 2008

Median daily AQI, 2008

Days above 100 in 2008

120

Days with an AQI in 2008 (of 366)

In 2008, EPA reported a daily Air Quality Index (AQI) for Walker, Alabama on 120 days. 42 of those days (35%) were in the Good range, and the median daily AQI was 56. That median is higher than the typical monitored county in Alabama (median 46 across 16 counties), and higher than the typical monitored U.S. county (44). The main pollutant was fine particles (PM2.5) on 120 days.

EPA did not report an AQI for every day of 2008 here (120 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 (2005, 2006, 2007, 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.

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 daily AQI
90th-percentile daily AQI

Main pollutant by day, 2008

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.

Pollutant	Days as main pollutant	Share of monitored days
Fine particles (PM2.5)	120	100%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
2011	107	43	64	0	0	53	69	86	PM2.5
2010	113	35	78	0	0	54	66	77	PM2.5
2009	118	57	61	0	0	52	66	76	PM2.5
2008	120	42	78	0	0	56	71	96	PM2.5
2007	117	27	88	2	0	59	81	115	PM2.5
2006	118	26	90	2	0	58	81	112	PM2.5
2005	116	31	83	2	0	58	79	113	PM2.5
2004	117	36	81	0	0	56	73	94	PM2.5
2003	104	24	78	2	0	58	74	106	PM2.5
2002	262	182	59	18	3	43	90	166	Ozone
2000	69	15	52	2	0	61	86	112	PM2.5
1999	103	27	69	7	0	65	86	116	PM2.5
1998	46	46	0	0	0	19	37	50	PM10
1997	56	56	0	0	0	18	31	43	PM10
1996	53	52	1	0	0	19	31	66	PM10
1995	56	55	1	0	0	23	37	58	PM10
1994	57	57	0	0	0	21	35	43	PM10
1993	56	52	4	0	0	23	42	58	PM10
1992	52	52	0	0	0	22	35	44	PM10
1991	55	51	4	0	0	23	47	66	PM10
1990	59	52	7	0	0	23	52	57	PM10

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 Alabama

Source: U.S. EPA AirData, “Annual AQI by County” files for 1990–2011 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem