ABSTRACT
Air pollution is a major problem in urban/industrial areas, like Tehran, and has several impacts on human health. This study aimed at assessing concentrations of criteria air pollutants [CO, SO2, NO2, O3, PM10] in Tehran, extracting patterns of hourly, daily, weekly, and monthly variations of concentrations, and making comparisons to National Standards and WHO Guidelines. Air quality data were taken from Air Quality Control Corporation and 5 sampling stations [out of 13] were selected for analysis according to data availability. Microsoft Excel 2003 was used for data analysis and plotting the charts. Patterns of temporal variation [hourly, daily, weekly, and monthly] of air pollutant concentrations were extracted. In some cases extracted patterns matched with the patterns proposed by other researchers. Pollutant concentrations were compared to National Standards and WHO Guidelines and it was observed that in most of the days, we exceeded the limit values. Air pollution in Tehran is quite high and there are many days that we exceed the standards; therefore appropriate control strategies are needed. Although the number of sampling stations is high enough to be representative of whole city, it is proposed that an independent sampling station is setup to check the validity of the measurements
ABSTRACT
The ever increasing rate of power consumption has led to an increase in public exposure to extremely low frequency magnetic fields [ELF-MFs] and brought severe concerns about their health effects. Considering previous studies and the facts about potential health effects of these fields, the present study aimed to evaluate the ELF-MF flux densities from power distribution lines near hospitals in Tehran. ELF-MF measurements were performed according to IEEE standard procedures-Std 644-1994 near the hospitals entrances using HI-3604 Power Frequency Field Strength Measurement System during three different time periods [i.e. 12-3 AM, 9-12 AM, 6-9 PM]. The results were analyzed using One-Way ANOVA Test. Mean, minimum, and maximum values of ELF-MF flux densities were 0.165 +/- 0.08 microT, 0.018 microT, 0.52 microT, respectively. There were no statistically significant differences in ELF-MF flux densities neither among different hospital groups nor among different time periods. The ELF-MF flux densities from power distribution lines around Tehran hospitals were much less than the standards values, implying that it can be considered only in epidemiological studies. In fact, in the case of powerful sources, magnetic field intensity is declined rapidly by distance and is limited to a few meters around the sources. This subject is considered as one of the main reasons for contradictory results in previous studies. Results of the present study can be used as a part of hospital patients' exposure to quantify the total exposure levels of patients as a critical and sensitive group in Tehran hospitals