Air Info Now: Data

Data

In the past, the answers to environmental questions were unavailable or often slow in coming. And when you did get them, chances are the answers were outdated and difficult to understand. To address this problem, in 1996 President Clinton directed the U.S. Environmental Protection Agency (EPA) to create a new program, Environmental Monitoring for Public Access and Community Tracking (EMPACT), to bring to people up-to-date environmental information they could understand and use every day.

Air Info Now and Pima County Department of Environmental Quality (PDEQ) are currently working on bringing this real-time air quality information to the public. This information will help communities and individuals make informed, day-to-day decisions about their lives.

Information is currently offered through these areas:

Air Monitoring Sites - Locations and Information
Current and Historic Hourly Air Pollution Data

Historic 24 Hour Particulate Data:

1995

1996

1997

1998

1999

2000

2001

2002

PM2.5

PM10

2003

2004

2005

2006

2007

2008

2009

2010

PM2.5

PM10

Air Quality Index Report (AQI)
Current and Historic Air Quality Index (AQI) Reports

Which of these AQI Reports should I use?

2010 Annual Air Quality Data Summary (PDF - 1,575 KB) - Summary of air quality monitoring data and trends in Pima County for the previous year (updated every summer for the previous calendar year).

2010 Annual Air Quality Data Summary - Appendix (PDF - 270 KB) - Compilation of historic air quality monitoring data for Pima County.

2010 Ambient Air Monitoring Network Plan (PDF - 4,300 KB)

Please note: Many of these reports display values for 1-hour PM10 and PM2.5 (particulate matter 10 and 2.5 microns or less in diameter) concentrations. These data values are provided for informational purposes only. The EPA Health Standard for PM10 and PM2.5 is a 24-hour standard, based on the average of 24 hourly readings from midnight to midnight. The EPA has not yet developed a 1-hour standard for PM10 or PM2.5.

National Ambient Air Quality Standards (NAAQS)¹

The Clean Air Act, which was last amended in 1990, requires EPA to set National Ambient Air Quality Standards for pollutants considered harmful to public health and the environment. The Clean Air Act established two types of national air quality standards. Primary standards set limits to protect public health, including the health of "sensitive" populations such as asthmatics, children, and the elderly. Secondary standards set limits to protect public welfare, including protection against decreased visibility, damage to animals, crops, vegetation, and buildings.

The EPA Office of Air Quality Planning and Standards (OAQPS) has set National Ambient Air Quality Standards for six principal pollutants, which are called "criteria" pollutants. They are listed below. Units of measure for the standards are parts per million (ppm) by volume, milligrams per cubic meter of air (mg/m³), and micrograms per cubic meter of air (µg/m³).

Pima County is currently in attainment (compliance) with the National Ambient Air Quality Standards for all of the criteria pollutants.

National Ambient Air Quality Standards

	Primary Standards		Secondary Standards
Pollutant	Level	Averaging Time	Level	Averaging Time
Carbon Monoxide	9 ppm (10 mg/m³)	8-hour ⁽¹⁾	None
Carbon Monoxide	35 ppm (40 mg/m³)	1-hour ⁽¹⁾	None
Lead	0.15 µg/m³ ⁽²⁾	Rolling 3-Month Average	Same as Primary
Lead	1.5 µg/m³	Quarterly Average	Same as Primary
Nitrogen Dioxide	0.053 ppm (100 µg/m³)	Annual (Arithmetic Mean)	Same as Primary
Particulate Matter (PM₁₀)	150 µg/m³	24-hour ⁽³⁾	Same as Primary
Particulate Matter (PM_2.5)	15.0 µg/m³	Annual ⁽⁴⁾ (Arithmetic Mean)	Same as Primary
Particulate Matter (PM_2.5)	35 µg/m³	24-hour ⁽⁵⁾	Same as Primary
Ozone	0.075 ppm (2008 std)	8-hour ⁽⁶⁾	Same as Primary
	0.08 ppm (1997 std)	8-hour ⁽⁷⁾	Same as Primary
	0.12 ppm	1-hour ⁽⁸⁾ (Applies only in limited areas)	Same as Primary
Sulfur Dioxide	0.03 ppm	Annual (Arithmetic Mean)	0.5 ppm (1300 µg/m³)	3-hour ⁽¹⁾
	0.14 ppm	24-hour ⁽¹⁾	0.5 ppm (1300 µg/m³)	3-hour ⁽¹⁾

⁽¹⁾ Not to be exceeded more than once per year.

⁽²⁾ Final rule signed October 15, 2008.

⁽³⁾ Not to be exceeded more than once per year on average over 3 years.

⁽⁴⁾ To attain this standard, the 3-year average of the weighted annual mean PM2.5 concentrations from single or multiple community-oriented monitors must not exceed 15.0 µg/m3.

⁽⁵⁾ To attain this standard, the 3-year average of the 98th percentile of 24-hour concentrations at each population-oriented monitor within an area must not exceed 35 µg/m3 (effective December 17, 2006).

⁽⁶⁾ To attain this standard, the 3-year average of the fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.075 ppm. (effective May 27, 2008)

⁽⁷⁾ (a) To attain this standard, the 3-year average of the fourth-highest daily maximum 8-hour average ozone concentrations measured at each monitor within an area over each year must not exceed 0.08 ppm.
(b) The 1997 standard—and the implementation rules for that standard—will remain in place for implementation purposes as EPA undertakes rulemaking to address the transition from the 1997 ozone standard to the 2008 ozone standard.

⁽⁸⁾ (a) The standard is attained when the expected number of days per calendar year with maximum hourly average concentrations above 0.12 ppm is < 1.
(b) As of June 15, 2005 EPA revoked the 1-hour ozone standard in all areas except the 8-hour ozone nonattainment Early Action Compact (EAC) Areas.