Actively Monitoring Air Quality

Ascon workers
Weekly onsite and offsite air monitoring for week of December 11th
Onsite Dust and VOC Monitoring Results

October 28th - November 3rd

Important note: Air quality was safely below conservative health-protective screening levels.

Ascon team member collecting data from air monitoring trailer offsite in 2019.

The following is live wind and weather data collected onsite. Seasonal rainfall totals are recorded from January 1 to December 31 each year.

Air Monitoring Approach

During cleanup activities, we are working to ensure the health and safety of the community by protecting air quality at the Site and in the local neighborhood.

Ascon’s air quality monitoring data since 2019 has consistently shown air quality has been safely below health-protective screening levels, including during active work. All air monitoring data is reviewed by DTSC and posted to asconhb.com.

  • Onsite Monitoring: Six onsite near real-time telemetry air monitoring stations for dust and total VOCs are located around the Site perimeter. Onsite workers will be monitoring downwind of excavations for odor and total VOCs.
  • Offsite Monitoring: Four offsite air monitoring trailers monitoring for VOCs, including trailers near Eader Elementary and adjacent to Edison High School. During excavation in areas with a higher potential of odor, dedicated personnel will be in the community downwind of excavation monitoring for potential odor impacts, and a community information table will be set up in Edison Park for community members to ask questions​.

Learn more about how Ascon conducted air monitoring during previous remedial fieldwork here, and learn more about air monitoring practices during 2019-2023 onsite activities here.

Air monitoring screening levels were approved by the Department of Toxic Substance Control (DTSC) and reviewed by South Coast Air Quality Management District (SCAQMD). Screening levels take several factors into account, including the type of substances that may be present, the concentration in the air and how long the exposure lasts. The levels are set to protect potentially sensitive members of the community (e.g., children, pregnant women, those with health concerns) and are for both short-term and long-term exposures, such as daily exposure over a lifetime.

While remedial fieldwork is paused, if the lab analysis results exceed health-protective screening levels for VOCs, we will:

  • Determine the source and necessary mitigation actions.
  • Share with DTSC and the community via this website.

Example of Health Protective Screening Levels Used for Monitoring Benzene

Benzine Graphic

Air monitoring is currently occurring at the following onsite perimeter locations:

* Map is for illustrative purposes only. Boundaries and locations shown are approximate.

Air Monitoring Glossary

An amount of a substance established by regulatory agencies that is protective of public health. Action levels are used during the work at Ascon to guide mitigation actions, stop work actions, and prompt increased actions to control potential odor, emissions or dust.

The air occurring at a particular time and place outside of structures. Often used interchangeably with “outdoor air”.

The periodic or continuous sampling and analysis of air pollutants in ambient air or from individual pollution sources.

See Full Glossary

Explainers