ABSTRACT
PM2.5 refers to particles with an aerodynamic diameter of less than 2.5 μm and is also known as fine particulate matter, including dust, dirt, soot, smoke, and liquid droplets. PM2.5 originates from both natural and anthropogenic sources (Alves et al. 2000). Some particulates are emitted naturally from volcano eruptions, dust storms, and forest and grassland fires. However, natural sources only make a small contribution to the total concentration, and anthropogenic sources are more important. For instance, human activities, including the burning of fossil fuels in road vehicles, power plants, and certain industrial processes, contribute a significant amount of fine particles. In addition, secondary aerosols derived from precursors emitted from various sources such as cars, trucks, power plants, and industrial facilities are also a major contributor. Secondary aerosol formation occurs because of chemical reaction in the atmosphere generally downwind a distance from the original emission sources (Hodan and Barnard 2004). Besides outdoor sources, PM2.5 is also produced by indoor activities such as cooking (e.g., frying). The composition of particles varies and depends on their sources. For example, mineral dust is generally made of mineral oxides. Primary aerosols that are directly emitted from emission sources into the atmosphere may include sulfur dioxide (SO2), nitrogen oxides (NOx), volatile
10.1 PM2.5 and Its Health Effects ......................................................................... 193 10.2 Remote Sensing Applications for PM2.5 Concentration Prediction .............. 195
10.2.1 Data ................................................................................................... 195 10.2.1.1 AOD Data........................................................................... 195 10.2.1.2 Fire Data ............................................................................ 199 10.2.1.3 LIDAR Data .......................................................................200
