The polyols arabitol and mannitol, recently proposed as source tracers for fungal spores, were used in this study to estimate fungal contributions to atmospheric aerosol. Airborne particulate matter (PM 2.5 and PM 10 ) was collected at Jianfengling Mountain, a tropical rainforest on Hainan Island situated off the south China coast, during spring and analyzed for arabitol and mannitol by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The average concentrations of arabitol and mannitol exhibited high values with averages of 7.0 and 16.0 ng m −3 respectively in PM 2.5 and 44.0 and 71.0 ng m −3 in PM 10 . The two tracers correlated well with each other, especially in the coarse mode aerosol (PM 2.5−10 ), indicating they were mainly associated with coarse aerosol particles and had common sources. Arabitol and mannitol in PM 10 showed significant positive correlations with relative humidity, as well as positive correlations with average temperature, suggesting a wet emissions mechanism of biogenic aerosol in the form of fungal spores. We made estimations of the contribution of fungal spores to ambient PM mass and to organic carbon, based on the observed ambient concentrations of these two tracers. The relative contributions of fungal spores to the PM 10 mass were estimated to range from 1.6 to 18.2%, with a rather high mean value of 7.9%, and the contribution of fungal spores to organic carbon in PM 10 ranged from 4.64 to 26.1%, with a mean value of 12.1%, implying that biological processes are important sources of atmospheric aerosol.

The Tibetan Plateau is one of the highest regions in the world, exerting profound influence on the large‐scale atmospheric circulation of Asia and the global climate. Here we report ambient concentrations of black carbon (BC), aerosol mass (PM2.5 and PM10) and associated carbonaceous species and water‐soluble inorganic ions from a remote mountain site in the southeastern part of the Tibetan Plateau during spring, in order to characterize the major sources contributing to the ambient aerosol in the background atmosphere of Southeast Asia. Significant build‐up of aerosol and BC concentrations was observed during a dry period, accompanied by the occurrence of fires and transport of pollution from the nearby regions of Southeast Asia and the northern part of the Indian Peninsula. The concentrations of BC, PM2.5 and PM10 mass reached maximum hourly values of 1470 ng m–3, 107 and 117 μg m–3, respectively. Organic carbon (OC), elemental carbon (EC) and sulfate were the predominant aerosol components. OC showed strong correlations with EC (R2= 0.93 for PM2.5 and 0.74 for PM10) and non‐sea‐salt potassium, especially in fine aerosol (R2= 0.95). In addition, the relative change rates of K+ against OC reached characteristically high values, highlighting the important contributions of biomass‐burning smoke.

With the aim of determining the impacts of various factors on commuter exposure to fine particulate matter (PM 2.5 ), a series of field studies were carried out to measure commuter exposure to PM 2.5 on six major commuting modes (in-cabin mode: bus, taxi and metro; on-roadway mode: walking, bicycle and motorcycle) in a highly industrialized city in the Pearl River Delta, China. The results showed that the exposure level was greatly influenced by the commuter mode, with the onroadway mode showing a higher PM 2.5 concentration (76 μg/m ). An experiment with the taxi mode suggested that the use of air-conditioning can effectively reduce exposure levels in most cases (by at least 83%). Apart from traffic-related emissions, ambient PM 2.5 concentration also had important impacts on exposure levels in most commuting modes, which was further ascertained by the seasonal variations in exposure levels and their significant correlations (p < 0.05) with meteorological parameters (temperature, relative humidity, wind speed and direction). The results of a General Linear Model analysis show that temperature, traffic mode and wind speed were significant factors that explained 27.3% of variability for the incabin mode, while relative humidity and wind speed were the significant determinants for the on-roadway mode, which contributed 14.1% of variability. In addition, wind direction was also an important determinant for both in-cabin and onroadway modes. This study has some valuable implications that can help commuters to adopt appropriate travel behavior to reduce their personal exposure to such pollutants.

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A new method for stable carbon isotope ratio analysis of anhydrosugars from biomass burning aerosol particle source filter samples was developed by employing Thermal Desorption--2 Dimensional Gas Chromatography--Isotope Ratio Mass Spectrometry (TD-2DGC-IRMS). Compound specific isotopic measurements of levoglucosan, mannosan, and galactosan performed by TD-2DGC-IRMS in a standard mixture show good agreement with isotopic measurements of the bulk anhydrosugars, carried out by Elemental Analyzer--Isotope Ratio Mass Spectrometry (EA-IRMS). The established method was applied to determine the isotope ratios of levoglucosan, mannosan, and galactosan from source samples collected during combustion of hard wood, softwood, and crop residues. δ(13)C values of levoglucosan were found to vary between -25.6 and -22.2‰, being higher in the case of softwood. Mannosan and galactosan were detected only in the softwood samples showing isotope ratios of -23.5‰ (mannosan) and -25.7‰ (galactosan). The isotopic composition of holocellulose in the plant material used for combustion experiments was determined with δ(13)C values between -28.5 and -23.7‰. The difference in δ(13)C of levoglucosan in biomass burning aerosol particles compared to the parent fuel holocellulose was found to be -1.89 (±0.37)‰ for the investigated biomass fuels. Compound specific δ(13)C measurements of anhydrosugars should contribute to an improved source apportionment.