Air Monitoring Network

California's ambient air monitoring network is one of the most extensive in the world, consisting of over 250 sites. US EPA requires that every state establish a network of air monitoring sites for criteria pollutants using criteria defined in the federal regulations for the monitoring sites location and operation. The Imperial County Air Monitoring Network established as early as 1986 is part of the overall California ambient air monitoring network. The monitoring purposes vary just as much as the populations, topography and geography varies in California. Like all regulated air monitoring networks, Imperial County's air monitoring network is required to be designed in such as manner as to provide ambient data that are representative of the area in which the residents of Imperial County live, work and play. Pollutants monitored in Imperial County include Ozone (O3), Particulate Matter with a diameter of 2.5 microns or less (PM2.5), Particulate Matter with a diameter of 10 microns or less (PM10), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2) and lead (Pb).

The Imperial County air monitoring network is designed to provide information to air quality managers at the federal, State and local levels about peak air pollution levels, typical levels, transport into and out of the County, levels of pollution at specific sources and the overall exposure to the population. In order to keep the public informed the Air District has established with the aid of the California Air Resources Board a real time Air Quality web page to help keep the general public informed regarding air pollution levels at any given hour. The site is located at

Below are annual net work plans that explain the monitoring objectives, areas of high concentrations and those areas impacted by transport. The most current plans are available below.

Site and Monitoring Information (Monitors reporting data in 2014)

Imperial County / CBSA: El Centro Metropolitan Statistical Area
Station/Address/AQS Site # OZONE 44201 CO 42101 NO2 42602 2 42401 PM2.5* 88101 PM10* 81102
Brawley Site Type: PopEx Gnrl, Trans
220 Main Street, Brawley Objective: NAAQS NAAQS
060250007 Purpose:         RConc/ Other Rconc
  Mon. Type:         SLAMS SLAMS
Calexico-Ethel^ Site Type: HConc/ Trans PopEx HConc PopEx (see footnote) HConc
1029 Belcher Street, Calexico Objective: NAAQS NAAQS NAAQS NAAQS   NAAQS
060250005 Purpose: EHConc RConc StateD RConc   StateD
El Centro Site Type: HConc PopEx PopEx   PopEx PopEx
150 S. 9th Street, El Centro Objective: NAAQS NAAQS NAAQS   NAAQS NAAQS
060251003 Purpose: EHConc RConc RConc   RConc RConc
Niland Site Type: PopEx         PopEx
7711 English Road, Niland Objective: NAAQS         NAAQS
060254004 Purpose: RConc         RConc, Other
  Mon. Type: SLAMS         SLAMS
Westmorland^^ Site Type:           PopEx
570 Cook Street, Westmorland Objective:           NAAQS
060254003 Purpose:           RConc/ other
  Mon. Type:           SLAMS

Currently the Air District is working with the California Air Resources Board in preparing the 5-year Network Assessment Progress Report to EPA