Abstract. Biomass burning activities are ubiquitous in China, especially in northern China,
where there is a large rural population and winter heating
custom. Biomass burning tracers (i.e., levoglucosan, mannosan and potassium
(K+)), as well as other chemical components, were quantified at a rural
site (Gucheng, GC) in northern China from 15 October to 30 November, during a
transition heating season, when the field burning of agricultural residue
was becoming intense. The measured daily average concentrations of
levoglucosan, mannosan and K+ in PM2.5 (particulate
matter with aerodynamic diameters less than 2.5 µm) during this study were
0.79 ± 0.75, 0.03 ± 0.03 and 1.52 ± 0.62 µg m−3, respectively. Carbonaceous components and
biomass burning tracers showed higher levels during nighttime than daytime,
while secondary inorganic ions were enhanced during daytime. An episode with
high levels of biomass burning tracers was encountered at the end of
October 2016, with high levoglucosan at 4.37 µg m−3. Based on
the comparison of chemical components during different biomass burning
pollution periods, it appeared that biomass combustion can obviously elevate
carbonaceous component levels, whereas there was essentially no effect on secondary
inorganic aerosols in the ambient air. Moreover, the levoglucosan / mannosan
ratios during different biomass burning pollution periods remained at high
values (in the range of 18.3–24.9); however, the levoglucosan / K+
ratio was significantly elevated during the intensive biomass burning
pollution period (1.67) when air temperatures were decreasing, which was substantially
higher than in other biomass burning periods (averaged at 0.47).
Characterization of PM1-Bound Metallic Elements in the Ambient Air at a High Mountain Site in Northern China
