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The objective of this work was to evaluate the indoor-outdoor particle size distribution in elementary schools located in central parts of Tehran and to evaluate those parameters that could be influencing the indoor particles concentrations in the classrooms. Concentrations of particles including PM10, PM2.5 and PM1.0, as some of the main air pollutants in Tehran, were measured in the schools, during winter 2009. It was found that the average indoor concentrations of PM10, PM2.5 and PM1.0 were 274 µg/m3, 42 µg/m3 and 19 µg/m3, respectively, while the outdoor concentrations for these particles were 140 µg/m3, 38 µg/m3 and 22 µg/m3, respectively. The main factors influencing indoor particle pollution were found to be the outdoor concentrations of the particles and the physical activity of the students, but other factors such as the differences between indoor and outdoor temperatures, class size dimensions and types of boards in the classrooms had negligible effects. [ABSTRACT FROM PUBLISHER]

Worsening environmental conditions in large cities of Iran, such as Tehran, are impeding economic development and creating adverse health consequences. As a common means of transportation, the number of different brands of motorcycles has grown rapidly in Tehran over the past few years. In this study the tail-pipe emissions of randomly selected 2- and 4-stroker have been measured and studied. Motorcycles currently being used in Tehran were tested for carbon monoxide (CO), carbon dioxide (CO2), and hydrocarbons (HC) and compared with emission standards already enforced in some Asian countries like China and Taiwan. It was found that the emissions of CO from some common 4-stroke motorcycles were much higher than from 2-stroke ones, while the CO2 emissions were almost equal to HC emissions for the 2-stroke motorcycles, which was approximately 14000 ppm for all brands. Except for one of the brand of the 4-stroke motorcycles, emissions of HC were less than 1000 ppm. [ABSTRACT FROM AUTHOR]