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https://hdl.handle.net/10217/181884

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Browsing Research Data by Subject "air quality"

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    ItemOpen Access
    Data collected during the pilot campaign of the citizen-enabled aerosol measurements for satellites (CEAMS) network in northern Colorado
    (Colorado State University. Libraries, 2019) Ford, Bonne; Pierce, Jeffrey R.; Wendt, Eric; Long, Marilee; Jathar, Shantanu; Mehaffy, John; Tryner, Jessica; Quinn, Casey; van Zyl, Lizette; L'Orange, Christian; Miller-Lionberg, Daniel; Volckens, John
    These measurement data were collected by participants using the Aerosol Mass and Optical Depth (AMOD) sampler during a pilot campaign for the Citizen-Enabled Aerosol Measurements for Satellites (CEAMS) network in Fall/Winter 2017 in northern Colorado. Data include multi-wavelength aerosol optical depth, filter mass and composition, and optical particle mass concentrations (for a subset of the files).
  • No Thumbnail Available
    ItemOpen Access
    Dataset associated with "Laboratory evaluation of low-cost PurpleAir PM monitors and in-field correction using co-located portable filter samplers"
    (Colorado State University. Libraries, 2019) Tryner, Jessica; L'Orange, Christian; Mehaffy, John; Miller-Lionberg, Daniel; Hofstetter, Josephine C.; Wilson, Ander; Volckens, John
    Low-cost aerosol monitors can provide more spatially- and temporally-resolved data on ambient fine particulate matter (PM2.5) concentrations than are typically available from regulatory monitoring networks; however, low-cost monitors—which do not measure PM2.5 mass directly and tend to be sensitive to variations in particle size and refractive index—sometimes produce inaccurate concentration estimates. We investigated laboratory- and field-based approaches for calibrating low-cost PurpleAir monitors against gravimetric filter samples. First, we investigated the linearity of the PurpleAir response to NIST Urban PM and derived a laboratory-based gravimetric correction factor. Then, we co-located PurpleAir monitors with portable filter samplers at 15 outdoor sites spanning a 3×3-km area in Fort Collins, CO, USA. We evaluated whether PM2.5 correction factors derived from periodic co-locations with portable filter samplers improved the accuracy of PurpleAir monitors (relative to reference filter samplers operated at 16.7 L/min). We also compared 72-hour average PM2.5 concentrations measured using portable and reference filter samplers. Both before and after field deployment, the coefficient of determination for a linear model relating NIST Urban PM concentrations measured by a tapered element oscillating microbalance and the PurpleAir monitors (PM2.5 ATM) was 0.99; however, an F-test identified a significant lack of fit between the model and the data. The laboratory-based correction factor did not translate to the field. Correction factors derived in the field from monthly, weekly, semi-weekly, and concurrent co-locations with portable filter samplers increased the fraction of 72-hour average PurpleAir PM2.5 concentrations that were within 20% of the reference concentrations from 15% (for uncorrected measurements) to 45%, 59%, 56%, and 70%, respectively. Furthermore, 72-hour average PM2.5 concentrations measured using portable and reference filter samplers agreed (bias ≤ 20% for 71% of samples). These results demonstrate that periodic co-location with portable filter samplers can improve the accuracy of 72-hour average PM2.5 concentrations reported by PurpleAir monitors.