10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
A Community Network of 100 Low-Cost Black Carbon Sensors
CHELSEA V. PREBLE, Julien Caubel, Troy Cados, Joshua Apte, Thomas W. Kirchstetter, University of California, Berkeley
Abstract Number: 1680 Working Group: Low-Cost and Portable Sensors
Abstract We developed a low-cost black carbon (BC) sensor that employs the filter-based light transmission method and field tested it to verify good precision and correspondence with current commercial black carbon instruments. We built over 100 of these BC sensors and deployed them as a connected air quality network in West Oakland, California. West Oakland is a mixed residential and industrial community that is adjacent to regional port and rail yard facilities and surrounded by major freeways. As such, the community is affected by diesel particulate matter emissions from heavy-duty diesel trucks, locomotives, and ships associated with freight movement.
In partnership with the Environmental Defense Fund, Bay Area Air Quality Management District, and West Oakland Environmental Indicators Project, we positioned the BC sensors outside of residences and businesses, along truck routes and arterial streets, along the Port of Oakland boundary, and at upwind locations. We operated this air quality network for 100 days beginning mid-May 2017.
Throughout the 100-day period, each of the 100 sensors transmitted data via a cellular network. A MySQL database was built to receive and manage the data in real-time. The database included diagnostic features to monitor each sensor's operational status and facilitate the maintenance of the network.
Spatial and temporal patterns in black carbon concentrations in West Oakland are observed to be driven by truck activity within the community. “Hot spots” exist along truck routes, near trucking facilities, and around businesses that use trucks to transport goods and materials. Almost everywhere, BC concentrations are higher on week-days than weekend-days, as is truck activity. The community-average black carbon concentration matches well the concentration measured at a centrally located site operated by the Bay Area Air Quality Management District. However, on average, 75% of locations within the community are more polluted than the centrally located monitoring site, with daytime average BC up to 1.75x higher. Daytime average concentrations along the Port of Oakland boundary and designated truck routes around the community are up to 3x higher than the central monitoring site average. Overnight, the spatial gradient within the West Oakland neighborhood diminishes, such that BC concentrations are more uniform. Areas downwind of the freeway, along the Port of Oakland boundary, and at some trucking facilities have persistent elevated BC concentrations in the evening and early morning hours.