posted on 2021-09-01, 20:03authored bySheng Xiang, Shaojun Zhang, Hui Wang, Yifan Wen, Yu Ting Yu, Zhenhua Li, Timothy J. Wallington, Wei Shen, Ye Deng, Qinwen Tan, Zihang Zhou, Ye Wu
The relative contribution (BCsfb/BCtr ratio)
of black carbon (BC) from traffic and solid fuel burning were evaluated
in different microenvironments. We used a mobile platform to measure
concentrations of BC and Delta-C (DC) in four microenvironments (diesel
plume, urban freeway, urban street, and rural freeway). A total of
38,661 measurements of BC and DC concentrations each averaged over
5 s (in winter 2018 and fall 2020) were used to evaluate the BCsfb/BCtr ratio. Measurements were divided into three
sampling campaigns (2018 nonholiday, 2020 nonholiday, and 2020 holiday)
to evaluate holiday and ambient temperature impacts on the BCsfb/BCtr ratio. There was a large reduction of BC
but not DC concentrations during holidays. We found elevated BCsfb/BCtr ratios in winter 2018 and fall 2020 that
can be related to residential heating and cooking, respectively. A
strong linear relationship (R2 = 0.89, p < 0.05) between DC/BC ratios and BCsfb/BCtr ratios in the four microenvironments is shown as evidence
that the DC/BC ratio is an indicator for solid fuel burning emissions
and is independent of sampling technique and location. The relationship
between DC/BC and BCsfb/BCtr ratios can be further
used to quantitatively discern BC contributions from traffic and solid
fuel burning emissions regardless of the type of microenvironments.