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More than a yearlong investigation (2008-2009) was carried in Srinagar, in the North-Western folds of Himalayas, involving the estimation of Total Suspended Particulate Matter (TSPM) and different carbonaceous fractions associated with it namely, Total carbon (TC), Elemental carbon (EC), Black Carbon (BC) Organic carbon (OC), no such direct estimates were available at that time for the valley and neither have they been updated till date. The samples collected on quartz filter using high volume sampler in a time series sequence and analyzed reflected marked seasonal dependence. The variability observed in carbonaceous contents of ambient aerosols was found to be similar as generally observed from other urban areas, however the relief along with prevalent meteorology was found to have a profound impact on the concentration of TSPM as well its constituent carbonaceous fractions. The higher values of TSPM were observed during summer months and the contribution of OC to TC as well. The contribution of EC to Tc was higher during colder months, EC arising from combustion sources attributed largely to petrogenic sources (fossil fuel) could be distinctly seen to be augmented by the biomass burning during autumn and winter; also increase in the OC content mainly starting in spring and continuing through to summer can be to attributed to active biogenic sources. [ABSTRACT FROM AUTHOR]

The deposition of light-absorbing aerosol (LAA) onto snow initiates processes that lead to increased snowmelt. Measurements of LAA, such as black carbon (BC) and mineral dust, have been observed globally to darken snow. Several measurement techniques of LAA in snow collect the particulates on filters for analysis. Here we investigate micro-quartz filters' optical response to BC experiments in which the particles are initially suspended in air or in a liquid. With particle soot absorption photometers (PSAPs) we observed a 20 % scattering enhancement for quartz filters compared to the standard PSAP Pallflex filters. The multiple-scattering correction factor (Cref) of the quartz filters for airborne soot aerosol is estimated to be ∼3.4. In the next stage correction factors were determined for BC particles mixed in water and also for BC particles both mixed in water and further treated in an ultrasonic bath. Comparison of BC collected from airborne particles with BC mixed in water filters indicated a higher mass absorption cross section by approximately a factor of 2 for the liquid-based filters, which is probably due to the BC particles penetrating deeper in the filter matrix. The ultrasonic bath increased absorption still further, roughly by a factor of 1.5, compared to only mixing in water. Application of the correction functions to earlier published field data from the Himalaya and Finnish Lapland yielded mass absorption coefficient (MAC) values of ∼7 –10 m 2 g -1 at λ=550 nm, which is in the range of the published MAC of airborne BC aerosol. [ABSTRACT FROM AUTHOR]

The deposition of light-absorbing aerosols (LAA) onto snow initiates processes that lead to increased snowmelt. Measurements of LAA, such as black carbon (BC) and mineral dust, have been observed globally to darken snow. Several measurement techniques of LAA in snow collects the particulates on filters for analysis. Here we investigate micro-quartz filters optical response to BC experiments where the particles initially are suspended in air or in a liquid. With particle soot absorption photometers (PSAP) we observed a 20 % scattering enhancement for quartz filters compared to the standard PSAP Pallflex filters. The multiple-scattering correction factor (Cref) of the quartz filters for airborne soot aerosol is estimated to ~3.4. In the next stage correction factors were determined for BC particles mixed in water and also for BC particles both mixed in water and further treated in an ultrasonic bath. Comparison of BC collected from airborne particles with BC mixed in water filters indicated approximately a factor of two higher mass absorption cross section for the liquid based filters, probably due to the BC particles penetrating deeper in the filter matrix. The ultrasonic bath increased absorption still further, roughly by a factor of 1.5 compared to only mixing in water. Application of the correction functions to earlier published field data from the Himalaya and Finnish Lapland yielded MAC values of ~7-10 m² g-1 at λ= 550 nm which is in the range of published MAC of airborne BC aerosol. [ABSTRACT FROM AUTHOR]