The South Coast AQMD recently adopted a first-in-the-nation testing protocol for low-cost Volatile Organic Compounds (VOC) sensors. The new protocol is now available to assist other air quality agencies, researchers, and sensor manufacturers to produce more accurate, reliable conditions for VOC sensors in laboratory settings. 

Major sources of VOCs in urban areas come from vehicle emissions, gasoline evaporation, and industrial sources. VOCs include a wide variety of chemical families including aliphatic hydrocarbons (alkanes), carbonyls (such as formaldehyde, acetaldehyde), aromatic hydrocarbons (such as benzene, toluene, xylene), and halogenated hydrocarbons (tetrachloroethylene). 

With recent advancements in sensor technology, the emergence of “low-cost” VOC sensors can offer faster, more cost-effective air quality monitoring. However, there is a lack of approved performance  procedures that can properly evaluate the sensors accuracy. So, as the nation’s premier air quality management agency, South Coast AQMD developed its own thoroughly researched, detailed testing protocol.

Conventional VOC monitoring relies on methods that are time consuming, labor intensive and expensive to operate, including calibration, sampling, sample storage, separation, and laboratory analysis. 

VOC sensors can be deployed more rapidly and easily than conventional regulatory grade equipment for specific near-source, fence-line and indoor monitoring applications. The results can provide a better understanding of levels of VOC emitted locally, as well as provide faster feedback to the public. 

The testing protocol outlines procedures South Coast AQMD is following for evaluating the performance of commercially available VOC sensors including chamber conditions of relative humidity, temperature, method detection limit safety measures and setup and installation procedures. 

All data collected, documentation developed, and testing results obtained from laboratory testing of VOC sensors project are organized and posted online at www.aqmd.gov/aq-spec.