Photoacoustic Measurements of Black Carbon Light Absorption/Scattering Coefficients and Visibility Degradation in Jordan During 2007/2008

Abstract

Air is the name given to atmosphere used in breathing and photosynthesis. Air supplies us with oxygen which is essential for our bodies to live. Air consists of 79% nitrogen, 20% oxygen, 1% water vapor and inert gases. Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to organisms into the atmosphere. Air pollutants are known as substances in the air that can cause harm to humans and the environment. These substances are not naturally found in the air at greater concentrations or in different locations from usual. Pollutants can be in the form of solid particles, liquid droplets, or gases. In addition, they may be arising from natural processes or human activities. Pollutants can be classified as primary air pollutants or secondary air pollutants according to their sources. Usually, primary air pollutants are directly emitted from a process, such as ash from a volcanic eruption, sulfur dioxide released from factories or the carbon monoxide gas from a motor vehicle exhaust. Secondary pollutants are not emitted directly. But, they form in the air when primary pollutants interact or react. An example of a secondary pollutant is ground level ozone, which is one of the many secondary pollutants that make up photochemical smog. Some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants. The primary air pollutants found in most urban areas are dispersed throughout the world’s atmosphere in concentrations high enough to gradually serious health problems. This problems can occurs quickly when air pollutants are concentrated. The main sources of pollutants in urban areas are transportation and fuel composition in stationary sources, such as commercial, coal-burning power plant, cooling, and industrial heating. One type of air pollution is the release of particles (aerosols) into the air from burning fuel for energy. Aerosols are defined as the relatively stable suspensions of solid or liquid particles in gas. There are many properties of particles that are important for their role in the atmospheric processes. These include number concentration, mass, size, chemical composition, and aerodynamic and chemical properties (Chang et al. 1982; Walker 1966). Of