Evaluation of dustfall in the air of yazd
Humar can not live without breathing air. Humar needs air even more than water and food. Average amount of air breathing by an adult is 15 kg in 24 hours while water and food using by adult is 2.5 and 1.5 kg. To consider how important of air, it is enough to know that people can continue to live without food for 5 weeks and without water for 5 days but without air can not continue to live more than a few minutes. In addition, it is very important for the human health. Unfortunately, nowadays air pollution is a universal problem and thousands of people suffer from this problem every moment (Hesam, 2005). Yazd is one of the cities with considerable air pollution. Dry weather in Yazd is due to vast desert around it. Most of the time the weather is stormy (sandstorm) which increase the dustfall. A method to measure the particles in the air is the dust fall Jar method. This method has been used in many foreign countries like India, U.S.A., Palestine and China. Previous research has shown that this method can estimate dust fall particles in the air of city (Crabtree, 2005). In Iran, only one or two researches have been done in this field (Pakseresht, 1977). This research has studied the amount of dust fall particles in the air of Yazd and its volatile and fix parts.