DOI: 10.5061/dryad.rn8pk0pnk
title: PurpleAir PM2.5 from the 2022-23 Florida agricultural-fire season

description: Smoke from agricultural fires is a potentially important source of fine
 particulate matter (PM2.5) in the US. Sugarcane is burned in Florida to
 facilitate the harvesting process, with the majority of these fires
 occurring in the Everglades Agricultural Area (EAA), where there is only
 one regulatory air quality monitor. During the 2022–2023 sugarcane burning
 season (October–May), we used public low-cost PurpleAir sensors,
 regulatory monitors, and 29 PurpleAir sensors deployed for this study to
 quantify PM2.5 from agricultural fires. We found satellite imagery is of
 limited use for detecting smoke from agricultural fires in Florida due to
 the cloud cover, overnight smoke, and the fires being small and
 short-lived. For these reasons, surface measurements are critical for
 capturing increases in PM2.5 from smoke, and we used multiple
 smoke-identification criteria. During the study period, median 24-hour
 PM2.5 concentrations increased by 2.3–6.9 µg m-3 on smoke-impacted days
 compared to unimpacted days, with smoke observed on 4–28% of the campaign
 days (ranges from the different smoke-identification criteria). Further,
 short-term PM2.5 increases were observed over 40 µg m-3 during smoke
 events. We contrast the region near the EAA with large populations of
 low-income and minoritized groups to the more affluent coastal region. The
 inland region experienced more smoke-impacted monitor days than the
 Florida east coast region, and there was a higher study-average smoke
 PM2.5 concentration in the inland area. These findings highlight the need
 to increase air quality monitoring near the EAA.
description: We deployed 29 PurpleAir PM<sub>2.5</sub> sensors in
 southern Florida during October 2022 - May 2023. PurpleAir sensors are
 low-cost devices (~$300 USD) that use light scattering techniques to
 estimate PM<sub>2.5</sub> mass (µg
 m<sup>-3</sup>). We performed several quality checks of the
 raw PurpleAir data (“CF1”) using the methods outlined in a previous study
 (https://doi.org/10.1029/2023GH000982). We took 10-minute averages of the PM<sub>2.5</sub> estimates and then removed data with the following conditions: (1) temperature &gt; 65 <sup>o</sup>C (0.0092 % of observations), (2) relative humidity &gt; 100% (0.0007 % of observations), (3) channel disagreement &gt; 10% from the average of the two channels or 10 µg m<sup>-3</sup> in the absolute difference between the channels (1.4 % of observations), and (4) measurements &gt; 500 µg m<sup>-3</sup> (0.0007 % of observations). We applied the Barkjohn et al. (2021) correction factor to all the quality-checked 10-minute average PurpleAir data from the deployment in Florida (https://doi.org/10.5194/amt-14-4617-2021). This correction factor was developed for the entire US and scales PM<sub>2.5</sub> based on measurement concentrations and relative humidity.
description: # Southern Florida PurpleAir PM2.5 data from October 2022 - May 2023
 [https://doi.org/10.5061/dryad.rn8pk0pnk](https://doi.org/10.5061/dryad.rn8pk0pnk) ## Description of the data and file structure This dataset includes PM2.5 concentrations from PurpleAir sensors which were deployed in southern Florida to monitor smoke from agricultural fires during October 2022 - May 2023. The locations of each monitor are reported and have been rounded for privacy of the monitor hosts. We report hourly averages of the data. For finer temporal resolution, please contact the authors. ### Files and variables #### File: PurpleAirData.csv **Description:** The data is formatted in a comma-separated values file. The following is a description for each column: ##### Variables * local_time: The timestamp associated with the PurpleAir measurements reported in Eastern Time. The format for this column is "Day/Month/Year Hour:Minute". * temperature: The temperature that is measured by the PurpleAir BOSCH BME280 reported in degrees Fahrenheit. * humidity: The percentage of relative humidity that is measured by the PurpleAir BOSCH BME280. * Uncorrected_PM25: The uncorrected PM2.5 reported in µg m-3. This data has been quality checked, as explained in the data description. * ID: The identification number for the associated PurpleAir sensor. * Corrected_PM25: The corrected PM2.5 reported in µg m-3. This data has been quality checked, as explained in the data description as well as corrected using the Barkjohn et al. (2021) correction factor. * Latitude: The latitude of the corresponding PurpleAir measurement site. This value has been rounded to the nearest 100th of a degree. * Longitude: The longitude of the corresponding PurpleAir measurement site. This value has been rounded to the nearest 100th of a degree.