To date only greenhouse gas emissions are usually considered for the evaluation of the climate effect of air pollution. However, the climate effect of the emitted primary aerosols and the secondary aerosols formed in the atmosphere is not negligible either. Sulfate aerosols are mainly considered as responsible for negative climate forcing. This component became less important because of the decreasing SO2 emission due to the introduction of flue gas desulfurization techniques at fossil power plants. Transport that consumes 30% of the primary energy, however, is responsible for three quarters of the formation of nitrate aerosol. The direct and indirect climate effects of aerosols are strongly dependent on their chemical composition and size distribution. The present project aims the characterization of primary aerosols emitted by the energy sector and secondary aerosols formed in the atmosphere that are relevant for climate effect. Since atmospheric aerosol is usually a mixture of different particle types, the description of the heterogeneity of the particles requires development and application of high-sensitivity measurement methods. The aims of the project are (i) the description of mixing of different components in individual aerosol particles and (ii) the determination of the chemical state of nitrogen in the aerosol fraction below 1 µm. These studies might result in useful atmospheric chemical information in addition to elemental composition of aerosols.
Development of sampling technique for high-sensitivity aerosol analytical
methods.
Sampling at fossil fuel burning power plants as well as in the vicinity of
a selected biomass burning boiler. Background aerosol sampling at two
locations.
Upgrading and validation of microanalytical methods capable of determining
the heterogeneity of the particles and the chemical state of nitrogen
using aerosol standards. Measurement of the aerosol samples collected
during the sampling campaigns using the upgraded methods.
Selection and application of dispersion model including chemical reactions
for description of the formation of sulfate and nitrate aerosol.
Comparison of the concentrations of secondary aerosols measured at high
time resolution with aerosol optical thicknesses calculated from satellite
images.
The resulted aerosol characteristics will be applicable to climate models,
thus the uncertainty of the calculated radiation forcing can be decreased.
The results of the project can also be utilized for the evaluation of the
environmental impact of the energy sector.