Abstract
Abstract. An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles) from Pudong (China) was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment) experiment in 2009. Data for organic and elemental carbon (OC and EC), organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs), and stable carbon isotopes OC (δ13COC) and EC (δ13CEC) were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA); high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = −24.5 ± 0.8‰ and δ13CEC = −25.1 ± 0.6‰) indicated that fossil fuels were the most important source for carbonaceous PM2.5 (particulate matter less than 2.5 micrometers in diameter), with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%; other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.
Highlights
The urbanization of China, coupled with rapid industrial development, has led to serious air pollution problems in many of the country’s large cities
The greater variability for organic carbon (OC) is presumably due to more complex sources for this carbon fraction, most especially those leading to the formation of secondary organic aerosol (SOA)
Our study shows that data for OC/elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and stable carbon isotopes in OC and EC obtained from single quartz-fiber filters provide insights into the sources, formation, and degradation of carbonaceous particles
Summary
The urbanization of China, coupled with rapid industrial development, has led to serious air pollution problems in many of the country’s large cities. We present data for carbonaceous aerosols, which were produced as part of an exploratory campaign called the Megacity Impacts on Regional and Global Environments (MIRAGE-Shanghai 2009, http://www.acd.ucar.edu/mirage). This project was conducted in collaboration with the Shanghai Meteorological Bureau. The broad objective of our specific component of this campaign was to obtain information on the chemical composition of carbonaceous aerosols, and the sources for these particles at the Pudong site in Shanghai. Specific objectives for our study were: (1) to document the variations of selected carbonaceous species during the MIRAGE-Shanghai 2009 Experiment; (2) to use diagnostic ratios for source identification; and (3) to quantitatively estimate the source contributions for carbonaceous aerosols
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