Multiple sulfur and oxygen isotope compositions in Beijing aerosol

Chemical and sulfur isotopic composition of precipitation in Beijing, China

“…Accordingly, the isotopic variations with time are interpreted to result from isotopic fractionation during equilibrium reactions. This was shown in a previous study for aerosol in Beijing air (Guo et al 2014). Seawater releases sulfate into the atmosphere by sea spray detached from the ocean surface.…”

Stable isotopic compositions of elemental carbon in PM1.1 in north suburb of Nanjing Region, China

“…Recently, stable isotopes have been used to trace and characterize the sources of the pollutants in the atmosphere due to that isotopic compositions are not generally same in different sources (Guo et al, 2010;Guo et al, 2014;Ma et al, 2010;Masalaite et al, 2015). Therefore, the studies on stable carbon isotope ( 13 C) of EC in PM 1.1 have a potential to seek for carbon sources in the atmosphere (Song et al, 2008;Wang et al, 2012).…”

Purification of BaSO4precipitate contaminated with organic matter for oxygen isotope measurements (δ18O and Δ17O)

“…The alumina crucible did not contain visible ash after combusting pieces of 0.2‐μm cellulose filter at 450 °C, 600 °C and 800 °C for 2 h, indicating that the cellulose filter (used to collect the precipitated BaSO 4 ) was completely combusted in an open air system above 450 °C. The results in Fig.…”

“…In some studies, a higher temperature treatment consisting of loading BaSO 4 into an alumina crucible and heating at 800 °C under air in an oven for 2 h has been used to remove OM trapped in precipitated BaSO 4 and to remove the cellulose filter used for precipitating BaSO 4 . The OM removal efficiency during such high‐T (800 °C) combustion is expected to be higher than that at 500 °C.…”

“…In some studies, a higher temperature treatment consisting of loading BaSO 4 into an alumina crucible and heating at 800 °C under air in an oven for 2 h has been used to remove OM trapped in precipitated BaSO 4 and to remove the cellulose filter used for precipitating BaSO 4 . The OM removal efficiency during such high‐T (800 °C) combustion is expected to be higher than that at 500 °C. However, at higher temperature (>500 °C), partial decomposition of BaSO 4 followed by isotopic exchange with the oxygen in air (O 2 and water vapor, among others) and/or container wall may occur, especially during high‐T treatment for several hours (personal communications from H. Bao and S. Halas in 2014 and 2015, respectively).…”