baharan emam

The aim of this study was to investigate the concentrations of PM10, PM2.5, O3, NO2, SO2, and CO in Tehran during March 2014-March 2018, and evaluate the effects of holidays and meteorological parameters on the air pollution levels. Hourly concentrations of PM10, PM2.5, O3, NO2, SO2, and CO in different air quality monitors of Tehran were acquired. The data from each air quality monitored were validated, and only high-quality monitors were included in this study. The 4-year averages of PM10, PM2.5, O3, NO2, SO2, and CO concentrations were 88.74 (μg/m3), 31.02 (μg/m3), 34.87 (ppb), 71.01 (ppb), 20.04 (ppb), and 3.78 (ppm), respectively. Higher concentrations of PM10 and O3 were observed during summer. In case of PM2.5 and CO, autumn and winter concentrations were higher than those in springer and summer. Lower concentrations of PM10 and NO2 in Fridays were observed comparing to other days of week. Ozone had high concentrations in Fridays as the weekend in Iran. Except for O3, all of the pollutants had higher concentrations in the working days, comparing to those in any type of vacation days. Concentrations of all pollutants rather that SO2 and O3 in Nowruz holidays were statistically lower than those in the working days. By controlling for the effects of meteorological variables, our results showed that the air pollution control policies and actions have been not effective for particulate matter. These results determines the time periods in which the concentrations of criteria air pollutants are high. This can be very useful for announcing alarms for citizens, and designing the air pollution control plans. In addition, more effective actions should be designed and implemented for reducing ambient levels of particulate matter.

This study aimed to determine the number of all causes such as lung cancer, chronic obstructive pulmonary disease (COPD), ischemic heart disease (IHD), and stroke deaths due to exposure to PM2.5 in Mashhad during March 2013-March 2017 using the AirQ+ model. Hourly concentrations of fine particulate matter were obtained from Department of Environment (DOE) of Iran, and validated according to APHEKOM study and WHO's criteria. Baseline incidence (BI) values for all-cause, COPD, lung cancer, IHD and stroke mortality was obtained from Ministry of Health and Medical Education. The annual average of (±SD) was determined for all four years and the average four- year were 36.07 (± 26.93), 27.29 (± 13.24), 30.53 (± 13.82), 30.14 (± 15.94), and 31.01 (± 10.22) µg / m3, respectively. The averages of PM2.5 concentrations during the cold months of years was higher than those in the warm months. Calculating the daily air quality index (AQI) indicated that only few days (48 days) during this period of time ( 4 years ) had a "standard" air quality and a concentration lower that 12.5 µg / m3. The total number of deaths in all the four years was 4457 cases. Furthermore, the total number of COPD, lung cancer, IHD, and stroke mortality was 146, 142, 5263, and 2608 cases, respectively. The trend of death numbers did not follow a specific direction, and some fluctuations can be observed. Due to the considerable health effects of the poor air quality in Mashhad, controlling actions should be implemented to reduce the levels of air pollution.

Traffic and mobile sources are possibly responsible to the most of the ambient volatile organic compounds (VOCs) in urban areas. This study aimed to measure and determine the traffic - related concentrations of benzene, toluene, ethylbenzene, xylenes, formaldehyde, and acetaldehyde at the main streets of Tehran, Iran.
The samples were taken from highly populated streets or main roads with heavy traffic in Central, Northern, Eastern, Southern, and Western areas of Tehran. In total, 33 points for BTEX and 23 points for formaldehyde and acetaldehyde were selected for sampling. The sampling and analysis were performed according to NIOSH methods 1501 and 2016.
The averages (± SD) of benzene, toluene, ethylbenzene, xylenes, formaldehyde and acetaldehyde concentrations in Tehran were 15.04 (± 9.18), 23.42 (± 8.73), 4.97 (± 2.55), 11.81 (± 4.46), 107.11 (± 30.58) and 57.10 (± 18.28) ppbv, respectively. Benzene concentrations were 3.30 to 26.00 times higher than air quality standard of European Union (5 μg / m3). High concentrations of BTEX and formaldehyde / acetaldehyde were found in central and eastern areas, respectively. High correlation coefficients were found between BTEX species (r = 0.77-0.95) and also formaldehyde and acetaldehyde (r = 0.98). The highest coefficient of variation (CoV) as a measure of spatial variability was observed for benzene (54.5 %).
The high outdoor concentrations observed in this study needs to be decreased immediately, especially in case of benzene.