Air monitoring and Sampling Strategies

Roaming Handheld Real-Time Air Monitoring

Air monitoring data is collected by field personnel using handheld instruments on a 24-hour basis throughout the duration of the air quality study. Chemicals evaluated using handheld instruments include hydrogen sulfide, benzene and volatile organic compounds (VOCs). Because handheld instruments are generally less sensitive than laboratory-grade analytical instruments, air monitoring data collected using these instruments is not intended for comparison to health-protective benchmarks (i.e., screening levels). These data help inform where further investigation is warranted. In this regard, handheld real-time air monitoring may be used to trigger the deployment of short-term air samples which are submitted for laboratory analysis.

Mobile Van Real-time Air Monitoring (PTR-MS Van)

A mobile van that uses proton transfer reaction mass spectrometry (PTR-MS) collects air quality data for a subset of compounds of interest while driving around communities surrounding the landfill. Data is collected between the approximate hours of 7:00 AM and 6:00 PM. The mobile van produces large data sets, as measurements are collected every few seconds. Data displayed on this website provide an illustration of average concentrations across defined regions (hexagonal cells) of the community. Additionally, minimum and maximum concentrations detected across those defined regions are displayed for each of the chemicals evaluated.

Fixed Location 24-hour Air Sampling

Air samples are deployed over consecutive 24-hour periods for continuous evaluation of air quality across fixed locations in the communities surrounding the Chiquita Canyon Landfill, as well as two background locations. Canisters are collected for testing and replaced each day.

Short-Term One-Hour Air Sampling

Air samples deployed for one-hour periods are deployed when benzene levels are detected twice within a 15-minute period by field personnel using handheld real-time air monitoring instruments. Results from these samples may be compared to California OEHHA Acute Reference Exposure Levels (RELs) or other applicable 1-hour values, where available.

Benzene is a colorless sweet-smelling chemical that is derived from both natural and manmade process. Common sources of benzene are oil, gas, and chemical manufacturing, gasoline engine combustion, forest fires, and cigarette smoke.

The California Office of Environmental and Health Hazard Assessment has established the following health-protective screening values for Hydrogen Sulfide

Health-Protective Screening Level for Short Term (1-hour) Average Exposures: 8 parts per billion (ppb)

Health-Protective Screening Level for Long Term Average Exposures: 1 part per billion (ppb)

Hydrogen Sulfide is a colorless gas described as having a “rotten egg” smell. It has a low odor threshold meaning people can generally smell it at very low concentrations. Naturally occurring hydrogen sulfide results from the degradation and/or digestion of plant and animal materials. As such, it is commonly found in areas around swamps, animal farming, and is even produced by bacteria living inside of your own body. Industrial sources of hydrogen sulfide typically include oil, gas, and chemical manufacturing, poultry and other animal processing facilities, as well as sewage treatment facilities.

The California Office of Environmental and Health Hazard Assessment has established the following health-protective screening values for Hydrogen Sulfide

Health-Protective Screening Level for Short Term (1-hour) Average Exposures: 30 parts per billion (ppb)

Health-Protective Screening Level for Long Term Average Exposures: 8 parts per billion (ppb)

Dimethyl Sulfide is a colorless gas described as having a “cabbage like” disagreeable odor. Naturally occuriing processes are responsible for the majority of emissions. Microbes such as bacteria, algae, and plankton create DMS as a biproduct of their lifecycles. Industrial sources of DMS include facilities that utilize microbial activity as part of their processes such as paper pulp mills, breweries, and landfills.

While no screening values intended to protect the public over repeated or sustained, long-term exposures have been developed for Dimethyl Sulfide, the American Industrial Hygiene Association has established a short-term (1-hour) average exposure value of 500 parts per billion (ppb) based on levels at which humans detect an easily noticed odor.