Paramount - Ongoing Air Monitoring Activities


Air Monitoring Update
South Coast Air Quality Management District (South Coast AQMD) has completed the most extensive hexavalent chromium air monitoring program conducted in the South Coast Air Basin to date and is now transitioning routine monitoring to the City of Paramount. South Coast AQMD will work closely with the City of Paramount’s contractors to ensure proper transition of air monitoring efforts.  Until then, South Coast AQMD will assist with a short-term sampling effort from July 2021-September 2021. 

  • Paramount Emissions Investigation Fact Sheet - April 2021:   English (PDF)  |  Español (PDF)


Updated Air Monitoring Plan for Paramount
In October 2016, South Coast AQMD initiated an extensive air monitoring campaign to assess levels of hexavalent chromium in the industrialized sections of the City of Paramount. Highly elevated levels were found initially and additional efforts were conducted to identify and address sources of hexavalent chromium that were be impacting nearby communities. South Coast AQMD’s ongoing air monitoring results indicate a substantial progress in reducing ambient levels of hexavalent chromium. As a result, the South Coast AQMD is updating its air monitoring efforts in Paramount to focus on conducting studies to evaluate other potential sources of hexavalent chromium and also monitoring other areas of the Basin that may have higher potential for air toxics exposure. South Coast AQMD will continue to perform sampling at selected locations within the Paramount community and this document outlines the updated monitoring plan for the city of Paramount.

Air Monitoring Data, Reports & Assessments

2021 Air Monitoring Update 
Between 2016 and 2021, South Coast AQMD conducted an extensive air monitoring campaign to identify sources of hexavalent chromium and other toxic metals. Air filter sample measurements were paused in December 2020 due to increased COVID-19 concerns. However, monitoring for multi-metals near Kindred Hospital continued. 

Hex Chrom Monitoring Sites
Location of hexavalent chromium monitoring sites active through December 2020 

Monthly Average Results of Hexavalent Chromium Near Facilities
Air monitoring results show substantial reduction of hexavalent chromium levels in late 2016/early 2017 at Aerocraft (site #8) and Anaplex (sites #14/#15). Overall, levels of hexavalent chromium have been consistently lower over the past two years at these sites. 

Compliance Sites

Toxic Metals with Long-Term Health Levels
Continuous multi-metals screening measurements are used to complement regular air monitoring to get a better understanding of emissions from nearby facilities. This, along with our monitoring data were used to provide a more complete picture in the Paramount area. This type of sampling has been used for four years at the Kindred Hospital. Toxic metals with long-term health thresholds (see below) are within typical (background) levels and well under long-term health-based exposure levels established by the Office of Environmental Health Hazard Assessment or the U.S. Environmental Protection Agency.

Background Concentrations  2020 Annual Average 



In 2013, the South Coast Air Quality Management District (South Coast AQMD) received a series of metallic odor complaints from local community members in Paramount. In response to these complaints, the South Coast AQMD staff began conducting an investigation into local sources of emissions, including initiating a local air sampling study. The purpose of these activities was to determine the source of emissions and potential air pollution control strategies. Ambient monitoring of toxic metal emissions began in 2013 at two sites on Vermont Avenue and California Avenue. Based on the monitoring results, there were two metals of concern: nickel and hexavalent chromium.  In 2014 and 2015, South Coast AQMD worked with Carlton Forge Works to reduce metal particulate emissions from its grinding operation. Carlton Forge Works implemented a number of voluntary measures that substantially reduced nickel levels. Since these measures did not reduce hexavalent chromium levels, the South Coast AQMD needed additional data to understand the source of these emissions. In October 2016, as part of its ongoing investigation to identify and address sources of hexavalent chromium that may be impacting the nearby communities, South Coast AQMD staff deployed several monitors in the mostly industrial areas of the City of Paramount. Initial results showed elevated levels of hexavalent chromium upwind of Carlton Forge Works. Results of monitoring efforts, South Coast AQMD Town Hall Meetings, air monitoring and public health reports, and other related information are posted on this website.

Summary of Efforts

The South Coast AQMD has undertaken unprecedented, extensive efforts to identify and reduce sources of hexavalent chromium in the City of Paramount. This Summary of Efforts in Paramount (PDF), summarizes the significant progress made and provides highlights of monitoring, enforcement, rule development, public outreach, and coordination efforts.

Potential Businesses with Metal-Related Operations in Paramount

Participating Agencies/Interagency Coordination

Los Angeles County Department of Public Health:

Related Information


Please contact us at 1-800-CUT-SMOG or file a complaint online, if you have information that can assist us in the investigation of sources of hexavalent chromium in the area. If desired, the information can be provided anonymously.

News Releases

More Information:

South Coast Air Quality Management District

21865 Copley Dr, Diamond Bar, CA 91765



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