Wind erosion, airborne particle production, their transport, deposition and accumulation on different natural and anthropic surfaces have always given rise to inconvenience for many people. During the last decades this phenomenon has become a very important international problem. A major effect of the atmospheric particles corresponds to the broad term of air pollution Air pollution is essentially caused by the presence of what is called « fugitive dust emissions ». The latter term denotes dust that is injected into the atmosphere by the combined effects of man's activity and the action of the wind, especially over farms, unpaved roads and other ground surfaces, industrial activity and re-suspension of particles by traffic flow. Wind-blown dust is also an efficient way to spread pathogens that are harmful to people, animals and plants. Particles less than 2 μm in diameter are retained in the human lungs. Some of these particles are pathogenic and may have a considerable negative impact on health. The field measurements (PM10 and PM2.5 concentrations), the laboratory analysis (particle size distribution, micromorphology, mineralogy, and chemistry) and the study of the data and the correlations with the atmospheric dynamics (especially its advective component), lead to the following general conclusion: the majority of the airborne particle concentrations measured in Brussels belongs to sources located out of the urban area. A smaller percentage of the particles originate from local sources. They are caused by different human activities: road traffic, domestic heating, building industry, general industrial activities, etc... Under dry weather conditions, wind and local activities may lead to the re-suspension of the coarser particles (between PM2.5 and PM10) formerly deposited on different urban surfaces. The formation of secondary aerosols (e.g. ammonium salts), under conditions with mild temperature and a relative high humidity range, seems to be an important contributor to the PM2.5 concentration. Recent EC directives on the allowed concentrations of PM10, PM2.5 and, especially, smaller particles in urban and rural areas imposes further investigations in order to determine with enough accuracy their origin, shape and chemical composition. As the recent outbreak of Saharan dust storm over the Brussels region has shown, the constant field monitoring, laboratory analysis and data study of extreme events involving airborne particles are an important part of our research program.
|Title of host publication||Impact, Monitoring and Management of Environmental Pollution|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||16|
|State||Published - 1 Jan 2011|