EVALUATION OF DUSTFALL IN THE AIR OF YAZD

Air pollution phenomenon in urban areas is a consequence of industrial revolution. Since air pollution destroys the environment, destruction, many countries have devoted research work to this issue and have developed considerable amount of programs to control air pollution. There are a lot of industrial activities in addition to sandstorms that lead to the spread of dust and particles in the air in Yazd city. In this work, dustfall and its relation with climate conditions in Yazd were determined. The study method was descriptive and cross-sectional. The sampling was done from 25/8/2005 to 19/3/2006 in 4 month long periods. (end of August-end of September), (end of September –end of October), (end of October-end of November), (19 February-19 March). The sampling was done in Jomhuri bulevard, Homafar Square, Shahid Beheshti Square, Seyd Gole Sorkh Ave. and Kashani Street by dust fall jar method. Results of this research shows that maximum concentration of dust fall was in the first period equal to 9.74 g/m².mo and minimum concentration was in the third period (October-November) and was equal to 3.13 g/m².mo. the maximum concentration was related to Homafar Square (8.91 g/m².mo) and the minimum concentration was related to Kashani Street was equal to 3.68 g/m².mo. Concentration average of dustfall in 4 the periods was 6.49 g/m².mo. The volatile part of dustfall was 50.6% and the fixed part was 49.4%. Correlations between concentration of dustfall, humidity, temperature, wind speed, and precipitation and the corresponding Pvalue were calculated and the results show that there is a direct relationship between the amount of dustfall and wind speed while humidity and precipitation are inversely proportional to the amount of dustfall. No relationship was found between temperature and dustfall concentration.