Iranian Journal of

Background and Objective: The aim of this study was to investigate dust origin particulate (PM_2.5) in Mashhad city in a long period of time (2014-2019) based on unhealthy days. Furthermore, changes in meteorological parameters and their relationship with dust storms have also been investigated.
Materials and Methods: In order to locate dust pollution hotspots in mashhad air, first, information about unhealthy days of Mashhad city in a 5-year period was obtained from the site of Mashhad Pollutants Monitoring Center and then HYSPLIT model was used to locate air pollution hotspots caused by particulate matter. To verify the results, the outputs obtained from this model were also compared with the DREAM8b model.
Results: By examining the meteorological parameters and its relationship with the outputs obtained from THEHYSPLIT and DREAM8b models, the maximum wind speed and relative humidity were obtained in autumn. There was no rainfall in the studied days (19 days) and the highest temperature was related to summer, indicating the relationship between the occurrences of polluted days due to particulate matter less than μ 2.5, wind speed and relative humidity in autumn. The results of the two models showed that the southern and northeastern regions of Mashhad city had the highest source of dust particles during the studied days.
Conclusion:  Although in previous articles, the origin of dust in Mashhad city was announced outside the geographical boundaries of the province, long-term investigation at low altitude (below 10m) showed that local origin of dust have an essential role in air pollution in Mashhad city under unstable atmospheric conditions. Inappropriate use of agricultural lands and severe changes in land use often in the northern region and implementation of construction projects such as the southern belt of Mashhad city play essential roles in increasing PM_2.5 particles in the air of Mashhad. This finding shows the importance of decision making for the implementation of soil stabilization projects etc... at the local level.

Background and Objective: Smoking is one of the biggest public health problems in the world, which can increase the overall burden of disease in the world. Since understanding the factors related to smoking among medical students is considered an important and necessary factor for formulating and explaining educational intervention programs, therefore, this study was conducted determine the prevalence of smoking among students of Kashan University of Medical Sciences and the factors related to it.
Materials and Methods: This cross-sectional study was conducted on 681 students of Kashan University of Medical Sciences in the first semester of 2018 by simple random sampling. Smoking in individuals, family, close friends, and other demographic characteristics was measured using a questionnaire with good reliability and multiple logistic regression was used for statistical analysis.
Results: The average age of the participants in this study (313 male and 368 female students) was 25 ±4.2 years old. The prevalence of smoking among students was 9.4% (16.7% in boys and 3.35% in girls). Also, smoking had a significant relationship with the desire to smoke, living in a dormitory, having close friends who smoke, and family members with a history of smoking (p<0.05).
Conclusion: The academic drop of students who smoke is significantly higher than other students. Since this study has shown the factors related to smoking in students, the use of these findings can be a basis for the prevention of smoking and the development of preventive interventions.