UNASSIGNED: Little is known about pollution in urban snow and how aerosol and gaseous air pollutants interact with the urban snowpack. Here we investigate interactions of exhaust pollution with snow at low ambient temperature using fresh snow in a temperature-controlled chamber. A @entity18683 -powered engine from a modern light duty vehicle generated the exhaust and was operated in homogeneous and stratified engine regimes. We determined that, within a timescale of 30  min, snow takes up from the exhaust a large mass of organic pollutants and aerosol particles, which were observed by electron microscopy, mass spectrometry and aerosol sizers. Specifically, the concentration of total organic @entity505 in the exposed snow increased from 0.948      0.009 to 1.828      0.001  mg/L (homogeneous engine regime) and from 0.275      0.005 to 0.514      0.008  mg/L (stratified engine regime). The concentrations of @entity7935 , @entity8336 and 13 out of 16 measured @entity2555 ( @entity2556 ), particularly @entity12683 , @entity9437 , @entity12684 and @entity3014 in snow increased upon exposure from near the detection limit to 0.529      0.058, 1.840      0.200, 0.176      0.020, 0.020      0.005, 0.025      0.005 and 0.028      0.005  ng/kg, respectively, for the homogeneous regime. After contact with snow, 50-400  nm particles were present with higher relative abundance compared to the smaller nanoparticles (<50  nm), for the homogeneous regime. The lowering of temperature from 25      1    C to (-8) - (-10)     1    C decreased the median mode diameter of the exhaust aerosol particles from 69  nm to 57  nm (p  <  0.1) and addition of snow to 51  nm (p  <  0.1) for the stratified regime, but increased it from 20  nm to 27  nm (p  <  0.1) for the homogeneous regime. Future studies should focus on cycling of exhaust-derived pollutants between the atmosphere and cryosphere. The role of the effects we discovered should be evaluated as part of assessment of pollutant loads and exposures in regions with a defined winter season.

Role of snow in the fate of gaseous and particulate exhaust pollutants from XXXX -powered vehicles.

@entity2555 :: ('MESH:D011084', 'Chemical') :: ['polycyclic aromatic hydrocarbons'] @entity3014 :: ('MESH:D001564', 'Chemical') :: ['benzo[a]pyrene'] @entity7935 :: ('MESH:D001554', 'Chemical') :: ['benzene'] @entity8336 :: ('MESH:D014050', 'Chemical') :: ['toluene'] @entity2556 :: ('CHEBI:33848', 'Chemical') :: ['PAHs'] @entity9437 :: ('MESH:C030935', 'Chemical') :: ['benz[a]anthracene'] @entity12683 :: ('MESH:C031721', 'Chemical') :: ['naphthalene'] @entity12684 :: ('MESH:C031180', 'Chemical') :: ['chrysene'] @entity18683 :: ('MESH:D005742', 'Chemical') :: ['gasoline'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon']
@entity18683 :: (MESH:D005742,Chemical) :: ['gasoline']
