TY - CHAP
T1 - Oxidative properties of ambient particulate matter - An assessment of the relative contributions from various aerosol components and their emission sources
AU - Verma, Vishal
AU - Sioutas, Constantinos
AU - Weber, Rodney J.
N1 - Funding Information:
This chapter primarily discusses the work conducted by the authors in the last ten years in the field of OP measurements for addressing these challenges by presenting results from various sampling campaigns in the western and southeastern United States. All of these campaigns were conducted under two research centers, i.e. Southern California Particle Center (SCPC) and Southeastern Center for Air Pollution and Epidemiology (SCAPE) funded by the United States Environmental Protection Agency (USEPA). The overall objective of SCPC was to investigate the underlying mechanisms that produce the health effects associated with exposure to PM, in relation to the sources, chemical composition and physical characteristics of PM, and with a focus on the unique urban settings of the Los Angeles air basin. Particularly, we present the results of OP measurements on the PM samples collected intermittently between Fall 2007 and Fall 2009, at an urban site near the University of Southern California (USC) in Los Angeles. We also include discussion of diesel exhaust PM samples collected under a different project (funded by California Air Resources Board) and analyzed for the OP measurement.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018
Y1 - 2018
N2 - The current national ambient air quality standards for PM 2.5 are based on particulate matter (PM) mass. Although epidemiological research conducted in the last few decades has associated PM mass with both respiratory and cardiovascular diseases, the heterogeneous and inconsistent nature of these associations suggests that not all components of PM are equally toxic. The capability of ambient particles to generate reactive oxygen species (ROS), also called the ROS activity or the oxidative potential is proposed as an alternative metric for relating the PM concentrations with health effects. In this chapter, we discuss our work on the measurement of oxidative potential of ambient PM from various sampling campaigns in the United States. The core objective of this work was to identify the components of ambient PM and their emission sources, which are most responsible for inducing the ROS generation. The role of organic compounds in the oxidative potential of PM was assessed by their removal using thermodenuder and solid phase extraction techniques, while the contribution of metals was quantified with a chelation technique. A class of water-soluble organic compounds characterized by their strong hydrophobicity known as humic-like substances or HULIS, and transition metals (particularly Fe, Cu, and Mn) were identified as the major species driving the ROS generation mechanisms in ambient particles. However, our work shows that there are strong synergistic and antagonistic interactions among the HULIS components and transition metals. Limited source apportionment results revealed that biomass burning and secondary organic aerosol are the largest contributors to the oxidative potential in the southeastern United States. Further studies in this direction should help to develop useful insights on the origin of PM toxicity leading to a better assessment of the human health effects of ambient PM pollution.
AB - The current national ambient air quality standards for PM 2.5 are based on particulate matter (PM) mass. Although epidemiological research conducted in the last few decades has associated PM mass with both respiratory and cardiovascular diseases, the heterogeneous and inconsistent nature of these associations suggests that not all components of PM are equally toxic. The capability of ambient particles to generate reactive oxygen species (ROS), also called the ROS activity or the oxidative potential is proposed as an alternative metric for relating the PM concentrations with health effects. In this chapter, we discuss our work on the measurement of oxidative potential of ambient PM from various sampling campaigns in the United States. The core objective of this work was to identify the components of ambient PM and their emission sources, which are most responsible for inducing the ROS generation. The role of organic compounds in the oxidative potential of PM was assessed by their removal using thermodenuder and solid phase extraction techniques, while the contribution of metals was quantified with a chelation technique. A class of water-soluble organic compounds characterized by their strong hydrophobicity known as humic-like substances or HULIS, and transition metals (particularly Fe, Cu, and Mn) were identified as the major species driving the ROS generation mechanisms in ambient particles. However, our work shows that there are strong synergistic and antagonistic interactions among the HULIS components and transition metals. Limited source apportionment results revealed that biomass burning and secondary organic aerosol are the largest contributors to the oxidative potential in the southeastern United States. Further studies in this direction should help to develop useful insights on the origin of PM toxicity leading to a better assessment of the human health effects of ambient PM pollution.
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U2 - 10.1021/bk-2018-1299.ch019
DO - 10.1021/bk-2018-1299.ch019
M3 - Chapter
AN - SCOPUS:85056285891
T3 - ACS Symposium Series
SP - 389
EP - 416
BT - Multiphase Environmental Chemistry in the Atmosphere
A2 - Nizkorodov, Sergey A.
A2 - Laskin, Alexander
A2 - Hunt, Sherri W.
PB - American Chemical Society
ER -