Detailed Physicochemical Characterization of the Ambient Fine and Ultrafine Particulate Mixture at a Construction Site

This paper presents a detailed characterization of the size and shape distributions, and chemical compositions of ambient fine and ultrafine particles collected at the site of a building demolition and construction project at the Pennsylvania State University. Particle samples were collected with a nine-stage cascade impactor, characterized via transmission electron microscopy and energy dispersive spectroscopy for elemental compositions, and images analyzed for morphological features. 89.3% of the particles collected by count were ultrafine particles or aggregates of ultrafine particles that disaggregated during the collection process. The mean particulate matter mass and count concentrations were 167.2 µg/m³ and 16,232 particles/cm³, respectively. 72.2% of the particles by count were morphologically circular on two-dimensional images and 74.0% of the particles by count had an aspect ratio of between 1:1 and 2:1. The five most prevalent elements found in the samples were carbon, oxygen, silicon, sulfur, and calcium, with corresponding mass fractions of 40.8%, 26.4%, 7.6%, 5.1%, and 4.7%. Based on the current regulatory occupational exposure limits, the particulate matter at the construction site was within permissible concentrations. These results enable a comparison of a real-world particulate exposure environment to hazard levels determined through single-particle-type exposure studies.