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Emissions Inventory

2011 Emissions Inventory Reports for PM10 and Ozone Precursors Published

February 2014 – MCAQD has prepared 2011 Periodic Emissions Inventory (PEI) reports for PM10 and ozone precursors. The PM10 emissions inventory includes emissions estimates for PM10, PM2.5 , NO x, SOx, and NH3, while the ozone precursor emissions inventory includes emission estimates for VOC, NOx and CO. Each report includes detailed descriptions of the calculation methods, activity levels, data sources, and other background information used to develop annual and daily estimates of emissions from a broad range of source categories. Emission estimates for each source category are provided for both Maricopa County as a whole, as well as the respective nonattainment areas. Click here to view or download the reports.

2013 Emission Inventory Surveys Distributed,
Annual Series of Workshops Concluded

May 2014 – Emissions inventory workshops to provide assistance in completing the 2013 reports have concluded for the 2014 calendar year. A new schedule of workshops will be posted in January 2015 for help in completing the 2014 reports. If you have questions regarding emissions inventories please call (602) 506-6790 or email for assistance.


The Maricopa County Air Quality Department's (MCAQD) Emissions Inventory (EI) Section collects, reviews, stores and manages stationary source air pollution emissions data for sources in Maricopa County. The EI Section also collects emission fees from Title V sources and provides data to county, state and federal agencies.

A point source emissions inventory shows annual air pollutant emissions for one specific business location. An emissions inventory may be requested by MCAQD of any facility with an air quality permit in Maricopa County. Each January, the EI Unit distributes reporting forms and instructions to those businesses that have been requested to submit an emissions report for the prior calendar year.

Annual emissions inventories serve a number of purposes:

  • They help determine a source's compliance with its air quality permit conditions as well as Maricopa County rules and regulations.
  • They help identify pollutant sources that may need new or additional controls, and thus provide a basis for improved air pollution control strategies.
  • They also provide a means of assessing progress in achieving reductions from existing controls.
  • They provide the basis for determining annual emission fees from Title V sources.
  • Inventory data are used as input for air quality modeling to demonstrate attainment of national ambient air quality standards (NAAQS).