Onsite Pilot Work Telemetry Air Monitoring

Onsite Telemetry Air Monitoring

A telemetry air monitoring system is collecting near real-time data during working hours while Ascon tests two odor mitigation technologies onsite, Engineered Misting Containment (EMC) and Soil Vaper Extraction (SVE). Work hours are from 7 a.m. to 6 p.m., Monday through Friday.

Telemetry-based air monitors around the active work areas capture air monitoring data in near real-time. The telemetry network records total volatile organic compounds (VOCs) and dust data upwind and downwind of the work area. Site contributions, concentrations detected downwind of the work area excluding upwind or background, are displayed and compared to the Site action levels, confirming air concentrations are below action levels.

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 the California Department of Toxic Substances Control (DTSC), available for review by the South Coast Air Quality Management District (SCAQMD), and shared on our Actively Monitoring Air Quality webpage.

Scroll down to learn more on how to read the Telemetry results.

View the latest Site Updates here.

Onsite Pilot Work Telemetry Results

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.

How to read the Telemetry results

If a dust, VOC or H2S reading is above their action level, it does not mean that the community’s health is at risk, but allows onsite teams to adjust mitigation efforts.

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.

Air monitoring action levels were approved by DTSC and SCAQMD for total dust.

PM10 Contribution Chart

VOCs

The results during work hours show Site contribution VOC levels in two-hour intervals. Telemetry is a tool that can guide and inform active work.

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

PM10 Contribution Chart

Hydrogen Sulfide (H2S)

The results during work hours show Site contribution H2S levels in one-hour intervals. Telemetry is a tool that can guide and inform active work.

Air monitoring action levels were approved by DTSC for H2S.

Hydrogen sulfide (H2S) is a colorless gas that smells like rotten eggs. Hydrogen sulfide occurs naturally in crude petroleum, natural gas, volcanic gases and hot springs. It can also result from bacterial breakdown of organic matter that may occur such as in estuaries and wetlands. People usually can smell hydrogen sulfide at extremely low concentrations, down to a few parts per billion (ppb). The action level of 7 ppb is based on the health-protective screening level for continuous exposure for a lifetime, established by the California Office of Environmental Health Hazard Assessment (OEHHA).

PM10 Contribution Chart

Ascon 24/7 Air Quality Monitoring

Air monitoring during pilot work is being conducted in conjunction with Ascon’s ongoing air monitoring. In the map to the right, you can see the locations of telemetry stations 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

Telemetry 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 pilot work 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. 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 pilot 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.

Pilot Work Community Resources

For more information on the planned onsite pilot work, please see: