and thus the K
þ
/Al ratio in PD_HN was much lower than that in
PBJ.
Also for As which is a tracer for coal-
fi
red power plants, the
density of power plants is also smaller than the industries. Hence, it
was also possible that the backward trajectories that intercepted
Northern China were not representative of the areas around the
sampling site in Beijing. Overall, it was found that the plumes that
invaded the Huaniao Isle were well characterized of origin from
Northern China via the long-range transport.