title: Uncertainty assessment of source attribution of PM(2.5) and its water-soluble organic carbon content using different biomass burning tracers in positive matrix factorization analysis--a case study in Beijing, China.
abstract: Daily PM2.5 samples were collected at an urban site in Beijing during four one-month periods in 2009-2010, with each period in a different season. Samples were subject to chemical analysis for various chemical components including major water-soluble ions, organic carbon (OC) and water-soluble organic carbon (WSOC), element carbon (EC), trace elements, anhydrosugar levoglucosan (LG), and mannosan (MN). Three sets of source profiles of PM2.5 were first identified through positive matrix factorization (PMF) analysis using single or combined biomass tracers - non-sea salt potassium (nss-K(+)), LG, and a combination of nss-K(+) and LG. The six major source factors of PM2.5 included secondary inorganic aerosol, industrial pollution, soil dust, biomass burning, traffic emission, and coal burning, which were estimated to contribute 31±37%, 39±28%, 14±14%, 7±7%, 5±6%, and 4±8%, respectively, to PM2.5 mass if using the nss-K(+) source profiles, 22±19%, 29±17%, 20±20%, 13±13%, 12±10%, and 4±6%, respectively, if using the LG source profiles, and 21±17%, 31±18%, 19±19%, 11±12%, 14±11%, and 4±6%, respectively, if using the combined nss-K(+) and LG source profiles. The uncertainties in the estimation of biomass burning contributions to WSOC due to the different choices of biomass burning tracers were around 3% annually and up to 24% seasonally in terms of absolute percentage contributions, or on a factor of 1.7 annually and up to a factor of 3.3 seasonally in terms of the actual concentrations. The uncertainty from the major source (e.g. industrial pollution) was on a factor of 1.9 annually and up to a factor of 2.5 seasonally in the estimated WSOC concentrations.
authors.affiliation: RCE-TEA, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China; South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, China; Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. Electronic address: taojun@scies.org.
authors.forename: Jun
authors.initials: J
authors.lastname: Tao
authors.affiliation: Air Quality Research Division, Science Technology Branch, Environment Canada, Toronto, Canada.
authors.forename: Leiming
authors.initials: L
authors.lastname: Zhang
authors.affiliation: RCE-TEA, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China. Electronic address: zrj@mail.iap.ac.cn.
authors.forename: Renjian
authors.initials: R
authors.lastname: Zhang
authors.affiliation: RCE-TEA, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Wu
authors.affiliation: South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, China.
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Environmental Meteorology Forecast Center of Beijing-Tianjin-Hebei, Chinese Meteorological Administration, Beijing, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Environmental Meteorology Forecast Center of Beijing-Tianjin-Hebei, Chinese Meteorological Administration, Beijing, China.
authors.forename: Yixi
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
authors.forename: Junji
authors.initials: J
authors.lastname: Cao
authors.affiliation: College of Environmental Sciences and Engineering, Peking University, Beijing, China.
authors.forename: Yuanhang
authors.initials: Y
authors.lastname: Zhang
keywords: Biomass burning tracers; Source apportionment; Source profiles