Characterizing air composition of plumes from industrial plants using mobile measurements of volatile organic compounds

Using a novel Vocus Proton Transfer Reaction Time of Flight Mass Spectrometer (Vocus-PTR-Tof-MS or Vocus) with sub parts per trillion (ppt; 10⁻¹²) detection limits for volatile organic compounds (VOCs), mobile measurements were collected while driving in Texas. Near industrial plants, rich and complex atmospheric composition was detected including compounds known as air toxics. This warranted further investigation using QGIS, a geospatial analysis software; concentration maps were produced to identify exact pollutant hotspots and plume patterns. Results revealed that the plumes, pollution clouds from a point source, were composed of high levels of aromatics (e.g. benzene, acetaldehyde, styrene, phenol, toluene, xylene, and naphthalene), highly oxidized compounds, and other classes. These VOCs are not detected by conventional, low-cost air quality monitors that have been implemented in the areas. With schools, homes, parks, and more near the properties, air profiles should be better assessed for resident safety. With PTRwid software, a full mass spectrum signature of VOCs was produced for the plumes at these locations to fingerprint their air composition. Out of more than 1000 VOCs detected, data reduction and quality control retained over 550 VOC specific ions. Many of these compounds are often found in sources like heated asphalt, fossil fuel burning, and other combustion processes that are known to be harmful to human health if not regulated properly. The rich chemical fingerprints will allow researchers to identify numerous pollution sources therefore aiding in source identification. The concentration maps and pollution fingerprints allow insights into pollution plume composition near these types of facilities and can quantify the exposure that workers and nearby residents may be subject to.