Molecular Characterization and Seasonal Variation in Primary and Secondary Organic Aerosols in Beijing, China

Abstract

Biomass burning (BB) aerosols, primary biological aerosol particles, and secondary organic aerosols, are critical components of particulate matter in the atmosphere. In this study, saccharides, lignin/resin acids, biogenic secondary organic aerosols tracers, aromatic acids, and hydroxyacids/polyacids were measured in total suspended particles collected from April 2012 to March 2013 at an urban site in Beijing using gas chromatography/mass spectrometry. The concentration of levoglucosan was elevated during 18-20 June. The high ratio of levoglucosan to mannosan and low ratio of galactosan to mannosan in June demonstrated the influence of wheat straw combustion in the North China Plain via long-rang transport. Sucrose, glucose, and fructose were more abundant in April, the spring bloom season. The maximum trehalose content (298 ng/m 3 ) occurred during a dust storm (27-29 April) with the highest stable carbon isotope ratio (δ 13 C, À21.2‰) of total carbon. Fungal spore tracers (arabitol and mannitol) peaked in summer. The largest concentrations of the oxidization products of isoprene and α/β-pinene also occurred in summer. However, the β-caryophyllene tracer was much more abundant on long-lasting haze days in winter and was positively related to levoglucosan. The contributions of biogenic primary sources (plant debris, fungal spores, and BB) to organic carbon were estimated to be in range of 2.64-35.2% (11.8%), with BB being the predominant source. Biogenic secondary sources (isoprene, α-pinene, and β-caryophyllene) and anthropogenic secondary source (naphthalene) accounted for 0.23-10.9% (3.36%) of organic carbon with large contributions in summer and winter, respectively.

Arabitol, mannitol, and glucose as tracers of primary biogenic organic aerosol: the influence of environmental factors on ambient air concentrations and spatial distribution over France

“…lease microorganisms along with plant debris into the atmosphere, strong air motions induce higher dispersion. These observations are in good agreement with those previously reported (Jones and Harrison, 2004;Liang et al, 2013;Zhang et al, 2010Zhang et al, , 2015Zhu et al, 2018b). For instance Liang et al (2013) have found a negative correlation between wind speed and polyol concentrations, and the highest atmospheric fungal spores concentrations were observed for a wind speed range of 0.6 to 1.0 m s −1 .…”

“…These results highlight that ambient air temperature and humidity are key meteorological drivers of the annual variation cycles of polyol and glucose concentrations. Hot and dry ambient air conditions may decrease the metabolic activity of the microorganisms (e.g., microbial growth and sporulation) (Fang et al, 2018;Liang et al, 2013;Meisner et al, 2018). Finally, maximum ambient concentration levels for both SC and cellulose are observed in excellent temporal agreement with the harvest periods (late summer) at the OPE-ANDRA site (Fig.…”

“…In this context, atmospheric concentrations of specific sugar alcohols and/or primary monosaccharides (including glucose) have been previously quantified at sites in several continental, agricultural, coastal, or polar regions (Barbaro et al, 2015;Chen et al, 2013;Glasius et al, 2018;Li et al, 2018;Pietrogrande et al, 2014;Verma et al, 2018;Wan et al, 2019;Yan et al, 2019;Yttri et al, 2007). However, large datasets investigating their (multi)annual cycles and seasonal and simultaneous short-term variations at multiple spatialscale resolutions (i.e., from local to continental) are still lacking (Liang et al, 2013;Nirmalkar et al, 2018;Pietrogrande et al, 2014;Yan et al, 2019). Such records are essential to better understand the spatial behavior of primary sugar compound (SC) concentrations (i.e., glucose, arabitol, and mannitol) and PBOA emission processes and to isolate their potential key drivers (e.g., vegetation type and density, topography, weather conditions), which are still unclear (Bozzetti et al, 2016).…”

Answer to referee #1

“…These observations are in good agreement with those previously reported (Jones and Harrison, 2004;Liang et al, 2013;Zhang et al, 2010Zhang et al, , 2015Zhu et al, 2018b). For instance Liang et al (2013) have found a negative correlation between wind speed and polyol concentrations, and the highest atmospheric fungal spores concentrations were observed for a wind speed range of 0.6 to 1.0 m s −1 . One of the limitations of this study is that 4 d averaged observations do not allow us to evaluate the driver contributions that might explain some short-term events for which the influence of meteorological parameters such as rainfall or solar radiation could also be significant (Grinn-Gofroń et al, 2019;Heald and Spracklen, 2009;Jones and Harrison, 2004).…”

“…These results highlight that ambient air temperature and humidity are key meteorological drivers of the annual variation cycles of polyol and glucose concentrations. Hot and dry ambient air conditions may decrease the metabolic activity of the microorganisms (e.g., microbial growth and sporulation) (Fang et al, 2018;Liang et al, 2013;Meisner et al, 2018 Finally, maximum ambient concentration levels for both SC and cellulose are observed in excellent temporal agreement with the harvest periods (late summer) at the OPE-ANDRA site (Fig. 6).…”