Graeme Nowell Carvlin

Project title: Community Air Monitoring of Particulate Matter in Imperial County, CA

Degree: PhD | Program: Environmental and Occupational Hygiene (EOHY) | Project type: Thesis/Dissertation
Completed in: 2018 | Faculty advisor: Edmund Y. W. Seto


The Imperial Project was a collaboration between community organizations, academia, and state partners created to investigate levels of particulate matter, a criteria air pollutant, in the highly impacted community of Imperial County. Community-based participatory research (CBPR) techniques were used to ensure that community members were engaged in each step of the research process. To cost-effectively measure air quality levels at a high temporal and spatial resolution a new low-cost community air monitor was designed and deployed in a 40-monitor network. These monitors were calibrated to regulatory beta-attenuation monitors (BAMs) operated by the California Air Resources Board. The calibration equation was validated by siting a mobile version of the BAM monitor called an E-BAM at six sites throughout Imperial County. The relatively high spatial density of the community air monitoring network enabled the creation of a land use regression (LUR) model. The LUR model estimated PM2.5, PM less than 2.5 µm in diameter, and PMcoarse, PM between 2.5 and 10 µm in diameter, using land use and meteorology. Back-trajectory analyses were performed to help explain which wind conditions lead to high PM in Imperial County. The combined effect of wind speed, wind direction, and seasonality were explored using polar plots. These analyses, along with the estimated emissions and other information detailed in the Imperial County State Implementation Plans, provide a comprehensive view of the sources of particulate matter in Imperial County. Real-time data from the monitoring network is displayed on a public website, IVAN Air, run by the community group Comite Civico del Valle (CCV). CCV and other project partners have taken the information learned from this project and engaged community residents in learning about their air quality and the actions they can take to reduce their exposure. URI