Anthropogenic dust as a significant source of ice-nucleating particles
in the urban environment
Abstract
Anthropogenic dust is an important constituent of airborne particles in
the urban environment but its ice nucleation activity remains
uninvestigated. Here, we studied the sources and ice nucleating
properties of size-resolved particles in the urban atmosphere under
mixed-phase cloud conditions. The heat-resistant ice nucleating
particles (INPs) unexpectedly contributed ~70% of the
INPs in coarse mode at temperatures below −15 oC. Detailed size-resolved
particle chemical composition analysis showed that these INPs were
contributed by anthropogenic dust, such as traffic-influenced road dust.
A parameterization based on coarse particles was developed to predict
the anthropogenic dust INP concentration, due to their correlations on
concentration and similarity in chemical compositions. The
parameterization can be used for further evaluating the anthropogenic
dust contribution to INPs on a global scale. We suggest anthropogenic
dust associated with rapid urbanization will become an important factor
for urban climate change by altering the cloud microphysics.