10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Using Low-Cost Sensors (RAMPs) to Evaluate the Spatial and Temporal Variation of Fine Particulate Matter Concentration within Environmental Justice Communities Surrounding Large Industrial Facilities
REBECCA TANZER, Carl Malings, Allen Robinson, R. Subramanian, Albert Presto, Carnegie Mellon University
Abstract Number: 607 Working Group: Low-Cost and Portable Sensors
Abstract The state-of-the-art in air quality monitoring consists of a sparse network of precise reference instruments which give limited information on the spatial distribution of pollutants. Thus, there is value in reliable low-cost air quality monitors that can be deployed in large numbers to more accurately assess spatial variation in pollutant concentrations. One specific use case is to evaluate environmental injustice near industrial point sources. We have developed low-cost air quality monitors called Real-time Affordable Multi-Pollutant (RAMP) sensor packages. The RAMPs include light scattering nephelometers for measurement of fine particulate matter (PM2.5). A network of fifty RAMPs have been deployed throughout Pittsburgh, PA. A subset of nine RAMPs have been deployed within the Monongahela River Valley, an environmental justice region, with major industrial sources. The largest coke plant in the US located in Clairton and a steel mill in Braddock both contribute to the historic nonattainment of the Monongahela River Valley to National Ambient Air Quality Standards.
Nine RAMPs are currently deployed to capture a range of microenvironments near the point sources. Three RAMPs are west/southwest (typically upwind) of both the coke plant and steel mill. Three RAMPs are immediately downwind (within two miles) of the coke plant. The three remaining RAMPs are immediately downwind of the steel mill (within two miles). The distribution of RAMPs allows us to quantify changes in outdoor PM2.5 concentrations in both space and time; comparison of source-impacted RAMPs to RAMPs located upwind and in the Pittsburgh urban core allow us to evaluate the local contribution of these point sources.
There is substantial spatial variation in times and durations of elevated PM2.5 concentrations between test areas. PM2.5 concentrations near the steel mill, downwind of the coke plant, and upwind of the coke plant are higher than 12ug/m3 (the EPA annual average PM2.5 standard) for 32%, 33%, and 22% of the deployment time, respectively. The percent of the time that the hourly averaged PM2.5 concentration is above short-term (daily) standards set by the WHO (25ug/m3) for the steel plant location, downwind of the coke plant, and upwind of the coke plant are 8%, 10.6%, and 3.5% respectively. Even though these locations are less than ten miles apart significant differences exist between their PM2.5 concentrations.
The value of a distributed network of low-cost monitors is demonstrated by the fact that high concentration periods measured at one location are not always experienced at the other sites. For example, a period of over four hours measured concentrations above 60ug/m3 at the location downwind of the coke plant while no such elevated concentration event was recorded at the other test locations during the same period of time. Periods of elevated PM2.5 concentrations (incidents where the hourly averaged PM2.5 concentration was over 25ug/m3) lasting for over ten hours are more likely to occur downwind of the steel and coke plants than they are to occur upwind of the coke plant or in an urban Pittsburgh neighborhood. Further analysis will be conducted into assessing the PM2.5 concentration at additional downwind locations to determine the change in PM2.5 concentration over increasing distance from an industrial facility. Deployment of sensors at the original nine sites began in Spring 2017. Over a year’s worth of data at multiple sites will enable the analysis of seasonal changes in pollutant spatial heterogeneity within these environmental justice regions.