Stable hydrogen isotope composition of n-alkanes in urban atmospheric aerosols in Taiyuan, China

The hydrogen isotope compositions (delta D) of n-alkanes associated with particulate matter with a diameter of <= 10 gm from Taiyuan, China, during heating and non -heating periods were measured via gas chromatography isotope ratio mass spectrometry to reveal the spatial and temporal characteristics of five functional zones and to provide another constraint on atmospheric pollutants. The OD values of n-C-16 to n-C-31 during the heating and non -heating periods ranged from 235.9 parts per thousand to 119.8 parts per thousand and from 231.3 parts per thousand to 129.2 parts per thousand, respectively, but these similar spans had different distribution features. During the heating period, the OD distributions between non central heating and commercial districts were consistent, as were those between residential and industrial districts; the n-alkanes came from two or more types of emission sources. Coal soot might be the primary local emission source, but not the only source. During the non -heating period, the n-alkanes of n-C-16 to n-C-20 were more depleted in D with the increasing carbon number in all functional zones, but there was no rule for n-C-21 to n-C-31. Specifically, coal soot and vehicle exhaust might be the primary sources of n-alkanes for non central heating districts in the heating and non -heating periods, respectively, according to the OD distribution of n-C-18 to n-C-22; gasoline vehicle exhaust might be an n-alkane source, and the hydrogen isotope fractionation effect during the condensation process should be a pollution mechanism for the commercial district during the heating period; the OD distribution difference of n-C-16 to n-C-18 between the two periods in the residential and industrial districts was consistent, which indicates a similar source of fossil fuel combustion and a similar isotope fractionation effect during the non -heating period. (C) 2017 Elsevier Ltd. All rights reserved.