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Development and performance evaluation of online monitors for near real-time measurement of total and water-soluble organic carbon in fine and coarse ambient PM. | LitMetric

AI Article Synopsis

  • This study introduces two online monitors designed to measure total organic carbon (TOC) and water-soluble organic carbon (WSOC) in fine and coarse particulate matter (PM).
  • The monitors were tested under lab and field conditions, showing they can accurately measure TOC and WSOC concentrations in real-time, with findings aligning closely with established reference methods.
  • Results included diurnal profiles of fine PM-bound WSOC, revealing seasonal variations influenced by temperature and photochemical activity, and the monitors' data can support future pollution source investigations and health impact assessments in urban areas like Los Angeles.

Article Abstract

In this study, we developed two online monitors for total organic carbon (TOC) and water-soluble organic carbon (WSOC) measurements in fine (d < 2.5μm) and coarse (2.5μm < d < 10μm) particulate matter (PM), respectively. Their performance has been evaluated in laboratory and field tests to demonstrate the feasibility of using these monitors to measure near real-time concentrations, with consideration of their potential for being employed in long-term measurements. The fine PM collection setup was equipped with a versatile aerosol concentration enrichment system (VACES) connected to an aerosol-into-liquid-sampler (AILS), whereas two virtual impactors (VIs) in tandem with a modified BioSampler were used to collect coarse PM. These particle collection setups were in tandem with a Sievers M9 TOC analyzer to read TOC and WSOC concentrations in aqueous samples hourly. The average hourly TOC concentration measured by our developed monitors in fine and coarse PM were 5.17 ± 2.41 and 0.92 ± 0.29 μg/m, respectively. In addition, our TOC readings showed good agreement and were comparable with those quantified using Sunset Lab EC/OC analyzer operating in parallel as a reference. Furthermore, we conducted field tests to produce diurnal profiles of fine PM-bound WSOC, which can show the effects of ambient temperature on maximum values in the nighttime chemistry of the winter, as well as on increased photochemical activities in afternoon peaks during the summer. According to our experimental campaign, WSOC mean values during the study period (3.07 μg/m for the winter and 2.7 μg/m for the summer) were in a comparable range with those of earlier studies in Los Angeles. Overall, our results corroborate the performance of our developed monitors in near real-time measurements of TOC and WSOC, which can be employed for future source apportionment studies in Los Angeles and other areas, aiding in understanding the health impacts of different pollution sources.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10795521PMC
http://dx.doi.org/10.1016/j.atmosenv.2023.120316DOI Listing

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