10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Comparison of PM-Bound Polycyclic Aromatic Hydrocarbons and Nitropolycyclic Aromatic Hydrocarbons in Urban Air in the WHO’s Western Pacific Regions
KAZUICHI HAYAKAWA, Ning Tang, Edward Nagato, Kanazawa University
Abstract Number: 301 Working Group: Aerosol Transport and Transformation
Abstract The combustion of fossil fuels and biomass produces many kinds of air pollutants such as carbon dioxide, sulfur oxides, nitrogen oxides, polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs). Large fractions of PAHs and NPAHs are found in airborne particulate matter (PM), especially fine particulate matter (PM2.5) which have a diameter no more than 2.5μm. Among these compounds, the International Agency for Research on Cancer (IARC) has classified benzo[a]pyrene (BaP) as a Group 1 compound (carcinogenic to humans), while dibenz[a,h]anthracene, 6-nitrochrysene and 1-nitropyrene (1-NP) are classified as Group 2A compounds (probably carcinogenic to humans). Moreover, 1,3-, 1,6-, 1,8-dinitropyrenes and 1-NP show strong direct-acting mutagenicity, and several PAHs and NPAHs show endocrine-disrupting and reactive oxygen species-producing activities. Recently, outdoor air pollution, including PM, has been classified into Group 1 by the IARC.
In this report, total suspended particulate matter was collected during the summer and winter seasons over two decades, in urban areas of more than 15 cities in the WHO’s Western Pacific Regions and South-East Asia. PAHs, including pyrene (Pyr) and benzo[a]pyrene, were determined using high-performance liquid chromatography (HPLC) with fluorescence detection and NPAHs, including 1-nitropyrene (1-NP), were determined using HPLC with chemiluminescence detection. The concentration ratio of 1-NP to Pyr ([1-NP]/[Pyr]), which increases with an increase in combustion temperature, was used as a source marker for all cities.
In the Western Pacific Regions, Chinese and Russian cities showed much higher PAH and NPAH concentrations than Japanese and Korean cities. Chinese cities showed significant differences by season (Winter > Summer) and latitude (North > South). The smaller [1-NP]/[Pyr] ratios in northern and central Chinese cities suggested that the major contributors were winter coal heating or biomass burning, while the larger [1-NP]/[Pyr] ratio in south Chinese cities suggested that the major contributor was automobiles. In South-East Asia, Vietnamese and Thai cities showed relatively high PAH and NPAH concentrations. The [1-NP]/[Pyr] ratio was smaller in the wet season but larger in the dry season, suggesting that the major contributors are automobiles (motor bikes) during the wet season and slash-and-burn agriculture in the dry season, respectively. Atmospheric BaP levels in several cities in the regions were still much higher than the standards of the WHO (0.12 ng m-3) and the EU and China (1 ng m-3). Recent regional air quality has changed dramatically from the point of view of PM-bound PAHs and NPAHs.