3. Conclusions
Using static TOF-SIMS to analyze aerosol surfaces on aerosol
particles collected within urban Beijing, we found that (1) PM1.1–2.1
and PM3.3–4.7 had similar surface chemistries, but the concentrations
of some ions and ionic groups were quite distinct between
PM1.1–2.1 and PM3.3–4.7. (2) Secondary inorganic compounds
(such as NH4HSO4 and NH4NO3), organic alkyl compounds (like
aliphatic compounds), and nitrogen-containing organic compounds
occurred on the surfaces of these aerosol particles.
Fluorides also were detected on their surfaces, suggesting that
more attention must be paid to controlling fluoride pollution in
urban environments. (3) The surface compositions of aerosol
particles were clearly influenced by air pollution levels; the
heavier the air pollution, the more complex were the surface
chemical compositions of aerosol particles. Wind, rainfall, and
air mass transport from the south also affected the surface
compositions of atmospheric aerosol particles in urban Beijing