AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Aerosol Chemical Speciation Monitor (ACSM) Inter-Comparison Study for Ambient Fine Aerosol Measurements in Downtown Atlanta, Georgia
SRI HAPSARI BUDISULISTIORINI, Manjula Canagaratna, Philip Croteau, Karsten Baumann, Eric Edgerton, Nga Lee Ng, Vishal Verma, Wendy Marth, Stephanie Shaw, Eladio Knipping, Douglas Worsnop, John Jayne, Rodney Weber, Jason Surratt, University of North Carolina at Chapel Hill
Abstract Number: 262 Working Group: Instrumentation and Methods
Abstract Currently, there are a limited number of studies that evaluate ACSM performance in the field. In the present study, we report on the inter-comparison of the ACSM with collocated continuous and integrated species and mass measurements at the Jefferson Street (JST) site located in Atlanta, GA, over different seasons.
Correlations of two collocated ACSMs result in high correlation (r$^2 > 0.8) for all chemical species, except for chloride (r$^2 = 0.66), with slopes and 1-standard deviations (1.03–1.09 ± 0.005–0.02). The ACSM chemical constituents are linearly correlated with the continuous (r$^2 > 0.7) and integrated (r$^2 > 0.6) measurements from the JST site, but correlations of nitrate and chloride in the summer are weaker (r$^2 < 0.4). Slopes of linear correlations of ACSM PM$_1 versus JST PM$_2.5 measurements for sulfate, ammonium, nitrate, and chloride are (0.87–1.12 ± 0.004–0.05), (1.05–1.31 ± 0.004–0.06), (1.73–2.79 ± 0.01–0.18), and (0.51–0.57 ± 0.04–0.07), respectively. OM/OC ratios from ACSM PM$_1 OM with that of OC PM$_2.5 from Sunset OC/EC Analyzer and filter measurements are (3.07–3.16 ± 0.01) and (2.81–2.77 ± 0.13–0.17), respectively. Large discrepancy found in nitrate measurements might be attributed to evaporation of nitrate from filter during warm periods and condensation of gas phase species on filters during cold periods. The possible contributions of organic nitrate signals to the measured ACSM nitrate concentrations are also investigated.
Correlations of the ACSM non-refractory PM$_1 plus EC with TEOM PM$_2.5 mass are strong (r$^2 > 0.7) with slopes (1.14–1.80 ± 0.02–0.09). The ACSM NR-PM$_1 correlations with FRM PM$_1 are very high (r2 > 0.8) with slopes (0.7–1.30 ± 0.05–0.21). Estimation of aerosol density from correlation of ACSM PM$_1 mass with SEMS-DMA-MCPC PM$_1 volume concentration yields a density of 1.66 ± 0.3 g cmS^-3.