Air Healthy to Breathe
Under the Clean Air Act, the U.S. Environmental Protection Agency is required to set and review National Ambient Air Quality Standards (NAAQS) for six common outdoor air pollutants (also known as “criteria” air pollutants): nitrogen dioxide (NO2), ground-level ozone (O3), sulfur dioxide (SO2), particulate matter (PM), carbon monoxide (CO), and lead (Pb).
Four of these pollutants (NO2, SO2, CO, and Pb) emit directly from a variety of sources. Ozone is not directly emitted, but is formed when oxides of nitrogen (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight. PM can be emitted, or it can be formed when emissions of NOx, sulfur oxides (SOx), ammonia, organic compounds, and other gases react in the atmosphere.
It is important for states to regulate these pollutants to minimize harmful health effects to Americans. Learn more.
Point Source Emissions
Carbon Monoxide (CO)
xx.x%
since xxxx
xx.x
in xxxx
(tons/yr)
Nitrogen Oxides (NOx)
xx.x%
since xxxx
xx.x
in xxxx
(tons/yr)
Sulfur Dioxide (SO2)
xx.x%
since xxxx
xx.x
in xxxx
(tons/yr)
Volatile Organic Compound (VOC)
xx.x%
since xxxx
xx.x
in xxxx
(tons/yr)
Particles 10 micrometers or less (PM10)
xx.x%
since xxxx
xx.x
in xxxx
(tons/yr)
Particles 2.5 micrometers or less (PM2.5)
xx.x%
since xxxx
xx.x
in xxxx
(tons/yr)
Ambient Air Pollution
In 1999, X out of x standards measured in Arizona were at or below the National Ambient Air Quality Standards (NAAQS).
Ambient (or atmospheric) air quality refers to the concentration of pollutants in the outdoor air. Ambient air is regulated by U.S. EPA and maintained by states through the NAAQS, which is the set of guidelines on acceptable concentrations of nitrogen dioxide (NO2), ground-level ozone (O3), sulfur dioxide (SO2), particulate matter (PM), carbon monoxide (CO), and lead (Pb). NAAQS seek to protect the public, especially “sensitive” populations such as asthmatics, children, and the elderly, from harmful ambient air pollutants.
For the purposes of ECOS Results, individual states had discretion with regard to the geographical scope of areas reported.
Percent Above or Below NAAQS Standard
The data reflects measurements taken in Maricopa County.
