A Comprehensive Analysis of the Air Quality in the NYC Subway System

University Transportation Centers Program2022PDFTech ReportGhandehari, MasoudAzad, ShamsConnected Cities for Smart Mobility toward Accessible and Resilient Transportation Center (C2SMART)New York University. Tandon School of EngineeringUnited States. Department of Transportation. University Transportation Centers (UTC) ProgramUnited States. Department of Transportation. Office of the Assistant Secretary for Research and TechnologyConnected Cities for Smart Mobility toward Accessible and Resilient Transportation Center (C2SMART)New York (New York)United StatesAir qualityAnalysisParticulatesSensorsSpatial analysisSubwaysRail transit facilities69A3551747124Spatial Distribution of PM included as Supplemental AttachmentWe have carried out a study analyzing the concentrations of particulate matter in the New York City subway system. Realtime and gravimetric measurements were made inside train cars along the full length of 9 subway lines, as well as real-time measurements on 341 platforms from 287 stations, all at one-second intervals that the mean (\ub1SD) PM2.5 concentrations on the underground platforms was 216 \ub1 82 \u3bcg/m3 versus 29 \ub1 27 \u3bcg/m3 for aboveground stations. Concentrations inside train cars were 148 \ub1 51 \u3bcg/m3 when traveling through underground tunnels and platforms, and 22 \ub1 44 \u3bcg/m3 while on aboveground tracks. US EPA\u2019s standards limit the allowable daily average PM2.5 mass concentration at 35 \u3bcg/m3. Using particle element analysis, we found that the concentration of iron particles in subway stations was 140 times higher than ambient outdoor levels. Other trace elements measured in the NYC subway system include silicon, copper, nickel, aluminum, calcium, barium, Manganese, and chromium. Results also suggest that when train cars are at stations with doors open, mixing of air between the platform and cars results in a rapid increase of PM concentrations in the cars.143