AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Applicability of Different Type Particulate Matter Sensors to Urban Air Quality Measurements
JOEL KUULA, Heino Kuuluvainen, Topi Rönkkö, Jarkko Niemi, Erkka Saukko, Harri Portin, Minna Aurela, Sanna Saarikoski, Rostedt Antti, Hilkka Timonen, Finnish Meteorological Institute
Abstract Number: 407 Working Group: Air Quality Sensors: Low-cost != Low Complexity
Abstract Dense monitoring networks are required for detailed spatiotemporal characterization of urban air quality. Conventional instrumentation is often conceived as bulky and expensive and hence inadequate to be used in monitoring networks. Prospective alternatives for these instruments are small sized and low-cost sensors specifically designed for network applications. However, as urban air composes of complex mixture of particles with different physical properties, it remains indefinite how sensors with reduced capabilities are best utilized in urban air quality monitoring.
Applicability of two different type particulate matter measurement techniques to urban air quality measurements were studied at a street canyon site in Helsinki, Finland. The measurement station was located in the immediate vicinity of a busy street which consequently highlighted vehicular exhaust emissions. However, long-range transported and street dust episodes were also observed. The tested sensors were a custom build optical Prototype Aerosol Sensor (PAS, utilized Shinyei PPD60PV and PPD42NS sensor modules as its detection units) and three commercial diffusion charging-based sensors (Pegasor AQ Urban, DiSCmini and Partector). Sensors were compared against Tapered Element Oscillating Microbalance (TEOM, PM2.5 and PM2.5-10) and Differential Mobility Particle Sizer (DMPS, lung deposited surface area) reference instruments. The results showed that the optical sensor was not able measure ultrafine particles emitted from vehicular exhaust emissions due to their small size (< 0.5 µm). However, it was able to observe local street dust and long-range transported particles with good accuracy. Diffusion-charging sensors were well-suited for measuring of vehicular emissions. These results highlight that supplemental sensor networks are best leveraged when the used measurement technique is chosen according to the features and limitations set by the specific environment. Additionally, the density of the measurement points should be determined according to the locality of the pollution sources as particles originating from longer distances (i.e. long-range transported) show much smaller city-scale spatial variability than e.g. local traffic.