فصلنامه سلامت و محیط زیست
سال ششم شماره 1 (پیاپی 19، بهار 1392)

Backgrounds and Precise air pollutants prediction، as the first step in facing air pollution problem، could provide helpful information for authorities in order to have appropriate actions toward this challenge. Regarding the importance of carbon monoxide (CO) in Tehran atmosphere، this study aims to introduce a suitable model for predicting this pollutant. We used the air pollutants and meteorological data of Gholhak station located in the north of Tehran; these data provided 12 variables as inputs for predicting the average CO concentration of the next day. First، support vector machine (SVM) model was used for forecasting CO daily average concentration. Then، we reduced the SVM inputs to seven variables using forward selection (FS) method. Finally، the hybrid model، FS-SVM، was developed for CO daily average concentration forecasting. In the research، we used correlation coefficient to evaluate the accuracy of both SVM and FS-SVM models. Findings indicated that correlation coefficient for both models in testing step was equal (R~0. 88). It means that both models have proper accuracy for predicting CO concentration. However، it is noteworthy that FS-SVM model charged fewer amounts of computational and economical costs due to fewer inputs than SVM model. Results showed that although both models have relatively equal accuracy in predicting CO concentration، FS-SVM model is the superior model due to its less number of inputs and therefore، less computational burden.

Weather pollution، caused by Ozone (O3) in metropolitans، is one of the major components of pollutants، which damage the environment and hurt all living organisms. Therefore، this study attempts to provide a model for the estimation of O3 concentration in Tabriz at two pollution monitoring stations: Abresan and Rastekuche. In this research، Artificial neural networks (ANNs) were used to consider the impact of the meteorological and weather pollution parameters upon O3 concentration، and weight matrix of ANNs with Garson equation were used for sensitivity analysis of the input parameters to ANNs. The results indicate that the O3 concentration is simultaneously affected by the meteorological and the weather pollution parameters. Among the meteorological parameters used by ANNs، maximum temperature and among the air pollution parameters، carbon monoxide had the maximum effect. The results are representative of the acceptable performance of ANNs to predict O3 concentration. In addition، the parameters used in the modeling process could assess variations of the ozone concentration at the investigated stations.

Microorganisms are the agents that can cause disruption in the biochemical and physiological reactions through mechanisms such as infection، allergy or toxic properties in the case of entering human body and if the body’s immune system be unable to destroy and eliminate biological agents، illness and even death will occur. This study evaluates air pollution (aerosol and bioaerosol) in different parts of a hospital in Tehran. We assessed and evaluated bioaerosols by applying 0800 NIOSH method using Bacterial sampler and specific cultures for bacteria and fungi separately in ICU (intensive care unit)، Pathology laboratory، Operating room، Recovery، and CSR (Central Service Room) of a hospital. The assessment showed that the average density of bacteria in the hospital studied was in the range of 1226. 88 - 294. 47 CFU/m3; the highest density was observed in the CSR and the lowest density measured was in the operating room. The bacteria identified included gram-positive bacillus (50. 6%)، Staphylococcus epidermis (20. 29%)، Staphylococcus Saprophyticus (2. 6%)، Staphylococcus aureus (7. 03%)، other Staphylococcus (5. 9%) and Micrococcus (13. 43%). Moreover، it was found that the average density of fungi was in the range of 0-188. 45 CFU/m3; the maximum density in ICU and the minimum density in operating room and recovery room. The fungi identified included Aspergillus flavus (31. 65%)، Aspergillus fomigatus (25. 17%)، Aspergillus niger (15. 82%)، and penicilliom (27. 33%). Comparison of bacteria density in different parts of the hospital with the recommended limits of ACGIH (500 CFU/m3) showed that density exceeded the limits in all units except in operating room whereas، density of fungi was less than the recommended limits of ACGIH (100 CFU/m3) in all units of hospital.

Exceeding the standard level in most cases، Tehran air pollution has become a national environmental challenge. Therefore، it is crucial to analyze Tehran air-pollution data set during 2000-2009 for trend analysis. In this study، we collected the hourly data of Tehran air pollution during 2000-2009 recorded by monitoring station of Tehran Air Pollution Control Company and statistical methods was used to determine the trend of the five pollutants، including: CO، PM10، SO2، NO2 and O3. The results indicate that average annual concentration of PM10، CO، NO2، SO2 and O3 has changed from 91، 11. 18، 102. 6، 46. 8، and 22. 1 at monitoring station in 2000 to 88 µg/m3، 3. 64 ppm، 66. 1 ppb، 21. 4 ppb، and 83 ppb in 2009 respectively. Our findings revealed that although the air quality in Tehran has improved in term of particulate matter، SO2 and NO2 during this decade as a result of government''s recent program in air pollution control، ozone concentration has increased.

Cyclone is one of the most utilized dust collectors for airborne particles control. It separates particles from airflow by centrifugal force. However، it is not effective in collecting very fine particles smaller than 10 μm in diameter. The aim of this study was to assess the performance of charging particles on cyclone efficiency in collecting particles smaller than 1 μm. To achieve the above aim، a pilot air conditioning system equipped with conventional cyclone of Lapple model was designed and installed. A high voltage (18 KV) DC power supply was used for charging silica particle in corona charger. Isokinetic probe was used for particles sampling at upstream and downstream of cyclone under different study conditions and measurement was carried out using Grimm 1. 08 dust counter. Charging fine airborne silica particles caused a significant increase in collection efficiency. There is a direct relationship between collection efficiency and charging voltage، so that the total particles collection efficiency was increased from 2. 7 to about 72% with respect of increasing charging voltage from zero to 18 Kv. However، inlet air velocity has a negative effect on the collection efficiency of particles charged. Applying electrocyclone in collecting fine particles smaller than 1 µm is more efficient compared with that of conventional cyclones.

Dust phenomenon has adverse effects on the health of the population. Due to the increasing concentration of Kermanshah dust phenomenon in recent years، The aim of this study was to measure the concentration of the sensitivity coefficients between dust phenomenon hospitalization and mortality rates for heart and respiratory. This was a descriptive study in which we studied the sensitivity coefficient of hospitalization and mortality rates for heart disease and respiratory to changes of dust concentration.. The study duration was during March-September 2010 and 2011. We collected the dust phenomenon data from Kermanshah Province Environmental Protection Department. The admissions and mortality of the cardiovascular and respiratory sufferers was collected from the Imam Ali، Imam Reza، and Imam Khomeini governmental hosiptals in Kermanshah. 1% increase in air pollution caused by the dust phenomenon will result in increasing about 0. 5 % of the respiratory patients، 1% cardiac patients، and about 0. 3% of the heart disease mortality. The relationship between dust phenomenon and respiratory sufferers was statistically not significant. We found that respiratory and cardiovascular hospital admission has a high sensitivity to dust phenomenon. This sensitivity has increased from 2010 to 2011. This sensitivity was greater for males than females. At least، during March-September 2010، for every 100% increase in the concentration of dust phenomenon، cardiovascular mortality increased by 29%. ject classid= «clsid: 38481807-CA0E-42D2-BF39-B33AF135CC4D» id=ieooui>

Tous gas power plant as an emission source of gas pollutants is located in the northwest of Mashhad City. This power plant is located in the neighborhood of various (linear، point and area) sources of pollution including Tous thermal power plant، Tous industrial town and motor vehicles; hence، it is not possible to determine precisely and accurately the share of these gases emission contribution at this power plant using conventional instruments. Therefore، we used modeling in order to estimate the dispersion of the pollutants emitted from this power plant. we used Screen 3 software using data of exhaust fume concentration، mass emission، chimney features of each unit، meteorology data، and fuel types consumed in order to model dispersion of NOx and SO2 emitted from Tous gas power plant having V94. 2 turbine equipped with DLN torches. Maximum concentration of NOx and SO2 at the distance about 30 km from the power plant was 1. 08 and 3. 69 µg/L respectively. The results of dispersion modeling of pollutants indicated that in most cases emission of air pollutants towards southeast. The NOx and SO2 concentration measured revealed that the concentration of these pollutants is lower than the standards of Clean Air Act.

According to the WHO estimates، air pollution is accounted for about 800000 premature death of cardiovascular and respiratory disease and lung cancer resulted from air pollution throughout the world; approximately 150000 cases of those deaths occur in south Asia. The studies conducting on short-term and long-term effects are reported in terms of admission rate، consulting with a physician، number of a particular disease، death، and years of the lost life (YOLL). We used Air Q2. 2. 3 (Air Quality Health Impact Assessment) Model to evaluate adverse health effects caused by NO2 exposure in Ahvaz City during 2009. NO2 reacts with ammonia، moisture، and other compounds to form small particles. These small particles penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease، such as emphysema and bronchitis، and can aggravate existing heart disease، leading to increased hospital admissions and premature death. First the data required was collected from Ahvaz Environment Organization and Meteorological Organization. Then، this data were processed by Excel software through correcting temperature and pressure، coding، averaging and filtering. Finally، the data processed were entered to Air Q model. This model is a valid and reliable WHO-proved tool to estimate the potential short term effects of air pollution. This model includes four screen inputs (Supplier، AQ data، Location، Parameter) and two output screens (Table and Graph). It was found that the Meteorological and Environment Organization stations have had the maximum and minimum NO2 concentration respectively. Moreover، the annual، summer، and winter average and 98cile of this pollutant was 27، 6، 43، and 115 µg/m3 respectively. The cumulative number of myocardial infarction resulted from NO2 exposure was estimated to be nine persons per year. This value for the cardiovascular death was found to be 19 cases. Finally، the COPD cases was estimated to be seven per year. Air Q software calculated relative risks، attributable proportion، and baseline incidence using data processed by Excel and presents the output as the cause specific deaths. It is noteworthy that there is no model that can estimate all of the pollutants health effects simultaneously. Cumulative number of persons for acute MI attributed to NO2 exposure was 9 in 2009. Moreover، 51% of this number occurred in the days with concentrations lower than 60 µg/m3. It should be noted that 72% of this value are corresponded to the days with concentrations below 90 µg/m3. The total cumulative number of cardiovascular death attributed to exposure with NO2 during one year of monitoring was 19 persons. 60% of these cases have occurred in days with NO2 levels not exceeding 90 µg/m3. Cumulative number of hospital admission of COPD attributed to exposure with NO2 during one year of monitoring was 7 persons. 87 % of these cases have occurred in days with NO2 levels not exceeding 110 µg/m3.