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Ô nhiễm không khí tại các khu vực đô thị là một vấn đề ngày càng tăng, do sự gia tăng kích thước của chúng, và hiệu ứng nó có thể có về sức khỏe cộng đồng, các loài sinh vật sống khác, các tòa nhà, và khả năng hiển thị. Hơn nữa, có là một xu hướng trên toàn thế giới đối với các thành phố lớn. Như vậy, theo Niên lịch Thế giới 1 (1994), có 45 thành phố với hơn 4 triệu dân vào năm 1985, lên đến 52 vào năm 1991. Điều này quá trình nguồn gốc để củng cố một trong. | 20 Analysis of Atmospheric Aerosols in Large Urban Areas with Particle Induced X-ray Emission Javier Miranda CONTENTS Introduction.405 Urban Aerosols.406 Basic Principles of PIXE Analysis.406 Sampling Procedures.408 PIXE Studies and Results.408 Conclusions.411 References.412 INTRODUCTION Air pollution in urban areas is a growing problem due to the increase in their dimensions and the effects it may have on public health other living species buildings and visibility. Moreover there is a worldwide tendency toward having larger cities. Thus according to the World Almanac1 1994 there were 45 cities with more than 4 million inhabitants in 1985 going up to 52 in 1991. This process gives origin to a reinforcement in health problems as the number of pollutant sources becomes greater in concentrated areas and more people are exposed to the emissions of those sources. The pollutants produced in large urban areas are also transported to surrounding zones or even remote sites thus worsening the air quality in those places also. Among air pollutants atmospheric aerosols are a special kind that is receiving increased attention because besides the aforementioned effects they may be responsible for a global temperature decrease produced by radiation reflection.2 In particular fine aerosols those having dimensions below 2.5 pm are capable of scattering solar radiation efficiently while additionally they can enter the respiratory tract and be deposited deeply in the lungs. Atmospheric aerosols are normally studied with one or more analytical techniques 3 which include atomic absorption spectrometry AAS ion chromatography IC neutron activation analysis NAA inductively-coupled plasma spectrometries ICP X-ray fluorescence XRF and particle-induced X-ray emission PIXE . None of them is individually capable of giving full characterization of the aerosols. However for analysis of elements having atomic numbers larger or equal to 13 i.e. heavier than Mg PIXE is the most suitable technique.4
