Sadat Feiznia; Rabbaneh Roughani; Saeed Soltani
Abstract
Particulate matters (PM) has a negative effect on human health especially in industrial and urban areas due to their great potential of reaching the furthest parts of human lungs. Therefore, it is essential to conduct continuous monitoring of PM in order to assess their spatial and temporal trend in ...
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Particulate matters (PM) has a negative effect on human health especially in industrial and urban areas due to their great potential of reaching the furthest parts of human lungs. Therefore, it is essential to conduct continuous monitoring of PM in order to assess their spatial and temporal trend in ambient air. This study aimed to assess the spatial and seasonal variations of PM2.5, PM10, total suspended particles (TSP) concentration and evaluating their correlations with meteorological parameters in surrounding regions of Isfahan city, Iran. PM2.5, PM10 and TSP concentrations (24-hours) were measured by gravimetry method with low volume air sampler for one-year period (July 2015-July 2016) at three stations located on western, eastern and southern part of Isfahan. The overall daily mean concentrations of PM2.5, PM10 and TSP were 73, 101 and 134 µg/m3 in east; 50, 86 and 103 µgr/m3 in the south; and 23, 45 and 53 µgr/m3 in west stations, respectively. This study identified that PM2.5 concentrations were above the US Environmental Protection Agency (EPA) guideline at all stations. The daily mean concentration of PM2.5, PM10, and TSP showed a negative correlation with humidity, while a positive correlation was observed between daily average temperature and all pollutant concentrations. A weak positive correlation was observed in case of wind speed. This study found that the meteorological condition has the highest impact on fluctuating PM2.5 concentration over the monitoring period. Pollution rose analysis indicated that westerly and north-westerly wind increased PM2.5 concentration at all sites.
Seyed Hamid Reza Sadeghi; Mohsen Zabihi; Mehdi Vafakh
Abstract
Regarding the undeniable role of rainfall erositivity factor in initiating water erosion, studying its different aspects is important in optimal soil and water resources management. It is taken in to account in many soil erosion estimation models which are used for soil and water conservation. However, ...
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Regarding the undeniable role of rainfall erositivity factor in initiating water erosion, studying its different aspects is important in optimal soil and water resources management. It is taken in to account in many soil erosion estimation models which are used for soil and water conservation. However, the impact of data length, study span, and the number of stations on variability of rainfall erosivity factor has been understudied. The present study therefore is an attempt to investigate the temporal variation of Wischmeier and Smith’s rainfall erosivity factor at different time scales and also the effect of data length, study span, and number of stations upon rainfall erosivity factor is scrutinized. Accordingly, the results of the present study with 70 stations, data span of 20 years and different study periods were compared with those obtained for another study with 18 stations and 23 years of data span. Rainfall erosivity factor of over 12,000 storm events was calculated in present study and mean values for different time scales were compared using t-Test. Results showed that the maximum and the minimum values of monthly rainfall erosivity factor in the country were different from each other. Besides, the results of t-Test showed significant difference between the calculated values of rainfall erosivity factor in some months (p<0.05) and seasons (p<0.05). Nonetheless, the difference between annual rainfall erosivity factor was not significant (p<0.05).
