Particulate Size Distribution and Sources Evaluation of n-Alkanes during Long-Term Haze Episode around Chaohu Lake, Eastern China

Abstract

ABSTRACTn-Alkanes (from nC 16 to nC 32 ) associated with particulate matters were determined in the ambient air around Chaohu Lake, Eastern China, from October to December in 2014 during a long-term haze episode. The total concentrations of particle bounded n-alkanes varied from 332 to 2500 ng m -3 , with the homologues of nC 24 -nC 30 the most abundant species. Spatial analysis revealed that low concentrations of n-alkanes existed at the sites close to Chaohu Lake, while high concentrations were generally at locations distant from the lake. For all aggregated fractions, most n-alkanes were distributed in fine particles with the mean geometric mean diameter (GMD) varying from 3.0 ± 0.6 µm for nC 16 to 2.1 ± 0.6 µm for nC 32 . Short chain n-alkanes were accumulated in coarse particles with a unimodal distribution, but long chain aliphatic hydrocarbons appeared to have a biomodal distribution in fine and coarse particles. The mass size distribution of individual n-alkane homologue was predominantly influenced by its volatility; thus GMDs were well correlated with the logarithmically transformed subcooled liquid vapor pressures (P L o , Pa) of n-alkanes at each sampling site, following the equation: GMDs = m g LogP L o + b g . Furthermore, m g and b g obtained from all locations tended to exhibit a significant linear correlation. This suggests that all saturated aliphatic hydrocarbons follow a similar accumulation mode during a haze episode, which allows us to predict the size distribution and GMD of a compound based on its P L o .

Size−resolved source apportionment of particulate matter from a megacity in northern China based on one-year measurement of inorganic and organic components

“…Most 12 steranes, hopanes and n-alkanes showed two peaks at 0.43-1.1µm in the fine mode and 3.3-5.8 µm in the coarse mode. The bimodal distribution of most n-alkanes was observed by Wang et al (2009), Lyu et al (2017) and Xu et al (2017). The size distributions of hopanes were reported as unimodal in the fine mode (Kleeman et al, 2008;Han et al, 2018), and can be bimodal during summer (Wang et al, 2009).…”

The Effects of Outdoor Source on Pollution Characteristics and Dynamic Changes of Particulate Matter in an Office

“…From Equations (1)- (6), it can be seen that, in summer, the indoor PM1 is more affected by the outdoor particle concentration; in winter, the indoor PM10 is more affected by the outdoor particle concentration. In addition, indoor particulate matter is more affected by outdoor particulate matter in winter.…”

“…At present, indoor air quality has become an increasing concern topic in architecture, medical hygiene, building environment, real estate, etc. [6]. It is also a research frontier of modern architectural science.…”