第三十一期TSI气溶胶论坛邀请到了美国Magee科技公司Anthony D.A. Hansen 教授 和 Griša Močnik博士, 报告信息如下：

时间：2015年10月26日9:30-11:30

地点：1102会议室

报告1: Aerosol Black Carbon: Interpretation of Measurements of Optical Absorption Spectrum in terms of Source Apportionment

报告人: Anthony D.A. Hansen教授

报告2摘要

Aerosol ‘Black Carbon’ (“soot”) is the world’s oldest pollutant. In pre-historic times, the life-span of primitive people was reduced by exposure to smoke from burning wood for cooking and heating. In classical and medieval times in Europe, wealthy people lived on the West (upwind) side of cities, while poor people lived on the East (downwind) side. In historical times, the ‘Coal Age’ of early industrialization covered Europe and the eastern USA with black smoke. The invention of the Diesel engine added to the burden of inhalable, micron-sized carbon particles coated with toxic compounds. In modern times, some parts of the world have successfully controlled these emissions: but many countries with rapidly-developing economies are seriously affected by particulate air pollution of combustion origin. Carbonaceous aerosols have many effects on the environment, all of which are harmful. These include impacts on public health; forcing for climate change; modification of precipitation; and degraded visibility. The emission of these primary aerosols from combustion sources can differ by orders of magnitude: they cannot be predicted simply from economic data on the amount of fuel consumed. Consequently, BC must be measured, and its sources must be identified. Different categories of combustion sources major contributions to carbonaceous aerosols. In modern times, diesel engine exhaust adds to ‘traditional’ emissions from the burning of biomass (residential wood combustion; forest fires; and agricultural burning) as well as coal combustion. Public policy must be based on good data: pollution cannot be regulated or reduced, until it can be measured and identified quickly and accurately. This requires source apportionment to reveal the important contributors. The Aethalometer® analyzes the aerosol at 7 wavelengths in real time. Different categories of emissions may have different optical absorption characteristics across the operational spectrum from 950 nm to 370 nm. Deconvolution of the data allows us to identify different characteristics and perform real-time source apportionment. We shall discuss the mathematical method, and present examples of the results from field observations in Europe and the USA.

报告2：INTERPRETATION OF THE LOADING EFFECT IN ABSORPTION FILTER PHOTOMETERS – DUAL SPOT AETHALOMETER MEASUREMENTS

报告人: Griša Močnik博士

报告2摘要：

Filter-based measurements of aerosol optical absorption are widely used to determine Black Carbon (BC) concentrations in real time. Measurements at multiple wavelengths permit the separation of contributions of BC from different combustion sources. Filter-based methods can suffer from non-linearity due increasing sample deposit on the filter. The dual-spot Aethalometer model AE33 provides a real-time determination of this loading effect, by determining the compensation parameter k in real time for each of the wavelengths. We present an interpretation of the compensation parameter k in terms of aerosol composition and mixing state. Optical properties of combustion aerosols were investigated under laboratory conditions. Optical properties of emitted aerosols varied greatly with the combustion regime. The type of combustion also influenced the parameter k, which is attributed to different particle coating thickness. In ambient campaigns, optical and chemical properties of aerosols were measured with high time resolution during summer and winter at different sites. The ratio of the sum of inorganic secondary and organic aerosol mass to BC (expected to be high for air parcels containing aged aerosols) correlates well with the parameter k measured by the AE33 at 880 nm. To investigate the influence of coating on parameter k, a drier and a thermodenuder were used to remove the coating. The results indicate that the compensation parameter k can be used for discrimination between fresh and aged aerosols. In the second part of the talk, I will present examples of measurements with the Aethalometers in the context of source apportionment studies, spatial heterogeneity of combustion aerosol from different sources and regional transport of air pollutants.