Chemical characteristics of submicron particulates (PM1.0) in Wuhan, Central China

• PM1.0 is a pollutant of regional concern in Central China.
• Water-soluble inorganic ion, carbonaceous fractions, and element species in PM1.0 were measured.
• Chemical species/ratios and enrichment factors were used to identify potential source.
• Two typical haze episodes were recorded during the sampling campaign.

Submicron particulate matter (PM1.0) samples were collected at a suburban site in Wuhan from Sept., 2012 to Aug., 2013. Concentration, composition, potential sources and acidity of the PM1.0 were investigated. The results indicated that the annual average concentration of PM1.0 was 81.7 μg/m3, with the highest and lowest values occurring in winter and summer, respectively. Inorganic water soluble ions constituted 48.9% of the PM1.0, and dominated by secondary species in the form of NH4NO3 and NH4HSO4. The high concentration of Pb (128.4 ng/m3) and greatly enriched Pb, Cd and Se in PM1.0 indicated contribution of coal combustion to PM1.0. Ratios of SO42 −/NO3− (1.3) and Cl−/Na+ (2.7) revealed the dominant stationary emissions, further confirming the coal combustion source in Wuhan. According to the chemical and meteorological analyses, biomass burning and stagnant weather were proposed to be the main causes to the haze episodes in autumn and winter, respectively.