Pit F Telemetry Air Monitoring

The Department of Toxic Substances Control (DTSC) has directed the excavation and transport of Pit F waste materials to a permitted landfill in Central California. This work is scheduled to start in June 2021 and conclude in August 2021.

A telemetry-based air monitoring network collects near real-time data during Pit F work hours. Work hours are from 7 a.m. to 6 p.m., Monday through Friday, and on Saturday if required.

In addition to 24/7 air monitoring conducted at the perimeter of the Site and at neighborhood stations, a telemetry-based air monitoring network is collecting additional air quality data during work hours for Pit F cleanup.

Telemetry-based air monitors around the Pit F tent capture a snapshot of air monitoring data. The Pit F telemetry network records total volatile organic compounds (VOCs) and dust data upwind and downwind of the Pit F tent. The Site contribution (concentrations detected downwind of the work area excluding upwind or background) are displayed and compared to the Site action limits, confirming air concentrations are below action limits.

If a brief telemetry reading is above an action level it does not mean that there was a harmful exposure or that the community’s health is at risk. Air monitoring 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. For the purposes of evaluating potential community exposures air data are evaluated over 24-hour periods and longer. The air data are submitted to DTSC, available for review by SCAQMD, and shared on Actively Monitoring Air Quality on asconhb.com.

If a reading is above an action limit, it does not mean that the community’s health is at risk. Scroll down to learn more on how to read the Telemetry results.

Pit F Telemetry Results

How to read the Telemetry results

Dust

The results during work hours show net dust levels in two-hour intervals. Telemetry is a tool that can guide and inform active work. If a brief reading is above 25 ug/m3, it does not mean that the community’s health is at risk but allows onsite teams to adjust dust mitigation efforts.

Air monitoring action limits were approved by DTSC and the South Coast Air Quality Management District (SCAQMD) for total dust.

PM10 Contribution Chart

VOCs

The results during work hours show Site contribution VOC levels in one-hour intervals. Telemetry is a tool that can guide and inform active work. If a brief reading is above an action limit, it does not mean that the community’s health is at risk but allows onsite teams to adjust work and mitigation efforts.

Air monitoring action limits were approved by DTSC and the SCAQMD for total VOCs.

PM10 Contribution Chart

To view data from the last week, last month, or all data, click on the calendar icon  icon and select the timeframe you would like to view for both dust and VOCs.

Ascon Air Quality Monitoring

Pit F air monitoring is being conducted in conjunction with Ascon’s ongoing air monitoring. In the map to the right, you can see the locations of Pit F telemetry monitors and ongoing onsite and offsite air monitors at upwind and downwind locations.

To learn more about Ascon’s onsite and offsite air quality monitoring data and approach, visit asconhb.com/air-monitoring.

Ascon air monitoring map

Frequently Asked Questions

A zero or negative value results when the upwind concentration is greater than or equal to downwind concentrations as determined by subtracting upwind data from downwind data for the “total net dust.” The Pit F telemetry charts show negative readings as zero. Monitors are placed in locations on the Ascon Site to determine dust entering from nearby properties (upwind) and in locations to determine the effectiveness of actions taken onsite to mitigate dust (downwind). Total net dust concentrations are compared to the Site action limits confirming air concentrations are below action limits.

A zero or negative value results when upwind concentrations are greater than or equal to downwind concentrations as determined by subtracting upwind data from downwind data for total VOCs. This occurs when offsite sources of VOCs such as car exhaust are greater than the levels of VOCs on Site.  Significant mitigation efforts onsite including soil stabilizers, managed excavation and the use of odor suppressants and neutralizers  control the levels of VOCs onsite. Telemetry data show VOC concentrations are below established action levels.

Equipment can periodically malfunction, despite quality control measures. Any issues are noticed promptly and documented during daily data collection by air quality technicians. Equipment malfunctions typically have been remedied within 24 hours. We are monitoring seven days a week, and 99 percent or more of the time, the equipment is functioning properly. Malfunctions occur for unforeseeable reasons like excess moisture in the atmosphere, tubing contamination or dilution of samples and issues with flow rate.

If one air quality monitor does not work, the community’s health is not at risk.

Yes, the stations are calibrated. The community air monitoring stations are checked each day and maintained by professional air quality technicians. These stations will continue to monitor total dust and collect samples for VOC laboratory analysis during the Pit F work. The equipment is routinely calibrated per manufacturers’ specifications. The Ascon Site construction manager reviews the information provided by the air monitoring team each day during active work. The field logs are maintained at the Site every day during active work and are available for review by DTSC and SCAQMD.

Yes, air monitoring  equipment is routinely calibrated per manufacturers’ specifications. Onsite monitors along the Site perimeter as well as additional Telemetry monitors are checked multiple times daily during active work and maintained by the air quality technicians.  The Ascon Site construction manager reviews the information provided by the air monitoring team each day during active work. Field logs are maintained at the Site every day during active work and are available for review by DTSC and SCAQMD.

Yes, air monitoring stations are checked multiple times daily during active work and maintained by professional air quality technicians with years of experience in this field.

Pit F Community Resources

For more information on the planned Pit F work, please see: