Global warming: knowledge and views of Iranian students

Study of students' knowledge about global warming can help authorities to have better imagination of this critical environmental problem. This research examines high school students' ideas about greenhouse effect and the results may be useful for the respective authorities to improve cultural and educational aspects of next generation. In this cross-sectional study, a 42 question questionnaire with mix of open and closed questions was used to evaluate high school students' view about the mechanism, consequences, causes and cures of global warming. To assess students' knowledge, cognitive score was also calculated. 1035 students were randomly selected from 19 educational districts of Tehran. Sampling method was multi stage. Only 5.1% of the students could explain greenhouse effect correctly and completely. 88.8% and 71.2% respectively believed "if the greenhouse effect gets bigger the Earth will get hotter" and "incidence of more skin cancers is a consequence of global warming". 69.6% and 68.8% respectively thought "the greenhouse effect is made worse by too much carbon dioxide" and "presence of ozone holes is a cause of greenhouse effect". 68.4% believed "not using cars so much is a cure for global warming". While a student's 'cognitive score' could range from -36 to +36, Students' mean cognitive score was equal to +1.64. Mean cognitive score of male students and grade 2 and 3 students was respectively higher than female ones [P<0.01] and grade 1 students [P<0.001] but there was no statistically significant difference between students of different regions [P>0.05]. In general, students' knowledge about global warming was not acceptable and there were some misconceptions in the students' mind, such as supposing ozone holes as a cause and more skin cancer as a consequence of global warming. The Findings of this survey indicate that, this important stratum of society have been received no sufficient and efficient education and sensitization on this matter

Air pollution: the knowledge and ideas of students in Tehran-Iran, and a comparison with other countries

Study of students' knowledge about air pollution can help authorities to have better imagination of this critical environmental problem. This research examines guidance school and high school students' ideas about air pollution and the results may be useful for the respective authorities to improve cultural and educational aspects of next generation. In this cross-sectional study, a closed questionnaire was used to examine knowledge and ideas of 2140 randomly selected school students of Tehran-Iran about composition of unpolluted air, air pollution and its causes and consequences. Cognitive scores were also calculated. Outcomes were compared with results of similar researches in Australia, Hong Kong and the United Kingdom. While a student's 'cognitive score' could range from -16 to +16, Iranian students' mean cognitive score was equal to +2.97. There was not significant statistical difference between girls and boys [P=0.32]. In response to question "most common gas in unpolluted air" nitrogen was mentioned by only 23.7%, While 45.1% of students mentioned oxygen. In general, student's knowledge was not acceptable and there were some misconceptions such as "supposing oxygen as the most prevalent gas in unpolluted air". The findings of this survey indicate that, this important stratum of society of Iran have been received no sufficient and efficient education and sensitization on this matter

Risk assessment of workers exposed to crystalline silica aerosols in the East Zone of Tehran

The term "crystalline silica" refers to crystallized form of SiO2 and quartz, as the most abundant compound on earth crust, is capable of causing silicosis and lung cancer upon inhaling large doses in course of occupational exposure. In this study, airborne respirable dust samples were collected on mixed cellulose filters [25 mm diameter, 0.8 mm pore size], by using a cyclone separator at the flow rate of 2.2 l/min for a maximum volume of 800 liters. Infrared absorption spectrometry was used according to the "National Institute of Occupational Safety and Health" [NIOSH] method No. 7602 for analysis of samples. Risk assessment techniques predictive of silicosis and lung cancer were employed. The geometric mean of workers' exposure to crystalline silica in ten industrial fields [stone milling and cutting, foundry work, glass manufacturing, asphalt, construction, sand and gravel mining, sand blast, ceramics, bricks and cement manufacturing] was in the range of 0.132 to 0.343 mg/m[3]. Mortality rate of silicosis was predicted to be in range of 1 to 52 per one thousand exposed individuals. Risk of lung cancer mortality in exposed workers in the east zone of Tehran based on geometric mean exposure of industrial activity and 45 years of exposure was in range of 50 to 129 per one thousand. In terms of risk assessment of silicosis mortality, cumulative exposure of 21 percent of population complied with the notion of acceptable risk. In regard to lung cancer mortality, 100 percent of the population were expected to have an unacceptable risk after 45 years of active work experience. This study is the first of its kind in Iran demonstrating a profile of exposure in different groups of workers in the east zone of Tehran's greater city, covering 5.5 million populations. Considering the total population of one hundred thousand workers exposed to quartz in east zone of Tehran and aging of the current young workforce, numerous cases of silicosis and lung cancer are forecasted in near future