ATMOCHEM - Interaction of trace gases with mineral dust: Impact on atmospheric photochemical cycles and dust properties

该项目包括矿物粉尘对大气/环境科学若干方面影响的实验（实验室）和理论（大气模型）研究。实验室研究的目的是调查几种重要的大气痕量气体在与大气有关的条件下与真实的（撒哈拉、中国、亚利桑那）和合成的空气中矿物气溶胶样品的相互作用。使用分散的空气尘埃样品（而不是散装基质）将使描述过程的物理化学参数能够以高置信度转移到真实的大气中。获得的参数包括吸收系数/能力和反应机制及其对大气变量的依赖性，如相对湿度，阳光照射强度和其他痕量气体的浓度。正在调查的痕量气体包括可能对大气NOy、NOx和HOx预算和O3混合比产生重大影响的大气物种。此外，实验数据将能够评估这种痕量气体相互作用对矿物尘埃的光学和云形成特性的影响。将在大气模型中评估实验室研究的过程的全球和区域影响，这些模型具有现实的粉尘排放计划，并测试了痕量气体气溶胶相互作用的表现，包括上述大气变量的影响。将在已知气相反应和其他气溶胶类型（硫酸盐和海盐）的现实框架内评估矿物粉尘在改变例如关键氮氧化物储存库、HO 2/ OH预算以及对对流层臭氧的直接和间接影响等浓度方面的作用。此外，还将评估矿物粉尘在运输过程中的化学老化/吸湿特性变化的影响，以及对光学特性和云/降水变化以及辐射收支的相关影响。一旦使用新的实验室数据进行改进，模型将能够提供更准确的结果，例如在不同的粉尘负荷情况下未来污染物排放的影响。

This project includes experimental (laboratory based) and theoretical (atmospheric modelling) studies of the impact of mineral dust on several aspects of atmospheric / environmental science. The laboratory studies are designed to investigate the interactions of several important atmospheric trace-gases with authentic (Saharan, Chinese, Arizona) and synthetic, airborne mineral aerosol samples under conditions which are relevant for the atmosphere. The use of dispersed, airborne dust samples (rather than bulk substrates) will enable the physical-chemical parameters that describe the process to be transferred with a high level of confidence to the real atmosphere. The parameters obtained include uptake coefficients / capacities and reaction mechanisms and their dependence on atmospheric variables such as relative humidity, intensity of irradiation by sunlight and concentrations of other trace gases. The trace gases under investigation include atmospheric species that are likely to have significant impacts on the atmospheric NOy, NOx and HOx budgets and O3 mixing ratios. Furthermore, the experimental data will enable assessment of the impact of such trace-gas interactions on the optical and cloud forming properties of mineral dust. The global and regional impact of the processes studied in the laboratory will be assessed in atmospheric models which have realistic dust emission schemes, and tested representations of trace-gas aerosol interactions including the effect of the atmospheric variables mentioned above. The role of mineral dust in changing concentrations of e.g. key NOx reservoirs, the HO2 / OH budgets and both direct and indirect impacts on tropospheric ozone will be assessed within a realistic framework of known gas-phase reactions and other aerosol types (sulphate and sea-salt). In addition, the effects of chemical ageing / changing hygroscopic properties of mineral dust during transport and the associated impact on optical properties and modification of clouds / precipitation and the radiation budget will be assessed. Once improved with the new laboratory data, the models will be in a position to provide more accurate prognoses of the effects of e.g. future pollutant emissions under different dust loading scenarios.