Speciated Volatile Organic Compound Measurements in Downtown Chicago

Abstract

Real time measurements of ambient volatile organic compounds were made using a Tofwerk’s PTR-ToF-MS equipped with an Aerodyne gas chromatography instrument in downtown Chicago (University of Illinois Science and Engineering South, 901 W Taylor St, Chicago, IL 60607) during the summer of 2023, from July 15th-August 21st. Instrument zeroes (both the real time Vocus and the GC) were taken after every file switch (at least one per hour), three real time calibrations were conducted each day, and one GC calibration was conducted each day (14 VOC Apel-Riemer standard). A strong near field source of select VOCs is evident (e.g. acetone). The attached data set includes a preliminarily and conservative indicator flag to identify these events using an adaptation of Jian Wang groups local pollution flag (Zheng et al., ACP 2018).