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Year long performance of Six PM Air Sensor Models Across Seven U.S. Sites
Citation:
Johnson, K., C. Johnson, S. Frederick, R. Yaga, B. Thomas, W. Schoppman, AND A. Clements. Year long performance of Six PM Air Sensor Models Across Seven U.S. Sites. Annual Conference of the American Association for Aerosol Research, Raleigh, NC, October 05 - 09, 2020.
Impact/Purpose:
Interest and concern about air quality has grown in recent years. Simultaneously, growth in the popularity and use of air sensors across the US has also occurred. However, adoption of this technology is limited due to uncertainty and variation in the quality of the data provided. This work evaluates the performance of a multiple low-cost air sensor models across the U.S.. It seeks to inform sensor users of potential data accuracy issues and long term performance applicable to both these sensor and other similar low-cost sensors. This work focuses on performance over a broader range of locations and longer time periods than much previous air sensor work. This abstract is for a presentation that will be made to the community of aerosol researchers attending the American Association for Aerosol Research (AAAR) Annual Conference being held virtually (Oct 5-9, 2020).
Description:
Particulate air sensor performance is often evaluated at a single site or in a single region over a time period from weeks to a few months. However, sensor performance is typically dependent on environmental conditions, pollutant concentrations, and particle properties. In addition, performance may change due to seasonal variations in particle properties, environmental conditions, and degradation of the sensor. To study these impacts on air sensor performance, five models of gas and particulate sensors, were set up in August 2019 for a yearlong study. An additional sensor type was deployed in March 2020. Sensors were collocated alongside a Federal Equivalent Method Monitor for PM2.5 at seven air monitoring stations throughout the United States and across climate regions. The sensor models were the Maxima from Applied Particle Technology, Clarity Node from Clarity Movement, PA-II-SD from PurpleAir, the AQY1 from Aeroqual, and the RAMP from SENSIT, with QuantAQ’s ARISense sensor deployed at the later date. PM2.5 sensors were evaluated for accuracy, precision, and the influences of environmental conditions, including temperature and relative humidity. Prior to deployment, sensors were evaluated and normalized based on a collocation period in Durham, North Carolina so that performance could be compared across sites independent of differences among sensors of the same type. Accuracy was evaluated monthly at each site so that comparisons could be made over time. Initial results suggest significant seasonal changes in performance, low precision between sensors of the same type for some sensor models, and large differences in sensor performance across sensor types. This work provides insights to improve sensor accuracy across optical PM sensors across the United States. Although this abstract was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.