“…V was retained as it is an important tracer of oil combustion (Liu et al, 2018;Wang et al, 2018). The Xact 625 has already been used in several studies (Chang et al, 2018;Gao et al, 2016;Phillips-Smith et al, 2017;Tremper et al, 2018). Due to malfunction of the instrument, data from the period of 11 February to 21 March are not available.…”