10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Indicating Black Carbon Exposure with a Smartphone App Using Image Analysis
Gang Chen, Mengxuan Cai, Bruce Urch, Frances Silverman, Yushan Su, ARTHUR W. H. CHAN, University of Toronto
Abstract Number: 1449 Working Group: Low-Cost and Portable Sensors
Abstract Exposure to indoor air pollutants leads to 4.3 million premature deaths each year (World Health Organization, 2012), mostly in low and middle-income countries. Particulate matter (PM) is a pollutant of special concern, which contributes significantly to those deaths. As one of the major components of fine PM (PM2.5) from combustion sources, black carbon (BC) has been suggested as a better indicator of harmful particulate substances than undifferentiated PM in studies of health effects, but current commercial BC sensors remain too costly to deploy widely. The objective of this project is therefore to develop an affordable and relatively accurate BC measurement method using a smartphone. Here we use image analysis to determine the amount of BC collected on a filter substrate. The image of the filter substrate is first obtained using a smartphone, and the darkness of the filter substrate is then determined by comparison to standardized colour panels. To obtain the relationship between the filter colour and BC mass, we have analyzed over 1300 filter samples collected across Ontario, Canada by the Synchronized Hybrid Ambient Real-time Particulate (SHARP) monitor with corresponding BC measurements. Results show a strong correlation (R2>0.92) between BC loading (measured by commercial BC instruments, e.g. aethalometer) and the colour information (RGB) obtained from the image, demonstrating the feasibility of our method. We also verify this model with further sampling from engine exhaust and personal sampling in Toronto and China. The outcomes of this project will lead to a relatively accurate method to measure BC exposure at significantly lower costs compared to commercially available BC sensors and can be used to inform the general public in developing countries about BC exposures.