International Journal of Occupational Hygiene
Volume:4 Issue: 1, Jan 2012

Noise is one of the major hazardous occupational exposures and one of the occupations at risk is the transportation industry. However, few studies have measured and reported the amount of noise exposure in drivers. In this study, we evaluated noise exposure among the public transportation bus drivers of one major Iranian city, Kerman, southeast Iran. Eighty public transportation buses in the streets of Kerman, Iran in 2010 were randomly sampled during week day business hours and in each driver noise exposure was measured for 10 minutes according to the standard methods. The noise exposure was measured in 4 different models of buses. All of the buses were 7 or fewer years old. There was no significant difference in the noise produced by the 4 models. The measurements were similar ranging from 65.9 dBA to 79 dBA. The noise pressure, measured in a range from 31.5 Hz to 8000 Hz, decreased from about 90 dBA to 50 dBA as frequency increased but was below 85 dBA in the speech frequencies. The noise levels measured in these buses for the drivers were under the 85 dBA threshold for speech frequencies, and by sure less than 85 dBA for the passengers; it will probably not cause hearing or other health related problems. However, more studies in this field are suggested.

Exposure to welding gases can cause health adverse effects. Risk assessment is a useful tool for good assessment of exposed workers. The purpose of this study was to determine the risk levels for exposed welders to welding gases. Welders (n=239) were selected from Iranian Natural Gas Transmission Pipelines Industry from four regions in Iran including Assaluyeh, Omidieh, Loshan, and Borujen. Ozone (O3) and nitrogen dioxide (NO2) samples were collected according to OSHA ID-214 method and NIOSH analytical method 6014, respectively. Direct reading instruments were used for sampling of carbon monoxide (CO) and carbon dioxide (CO2). A semi-quantitative method was used for risk assessment. Exposure to O3, NO2, CO, and CO2 ranged 0-0.0371, 0.01-0.58, 0.375-4.33, and 89.5-1395.44 ppm, respectively. Among welders, Back weld group had the maximum exposure to O3, CO, CO2, while the maximum exposure to NO2 was seen for Filling group and then for Back weld group. Although average exposure values were significantly lower than Threshold Limit Values-Time Weighted Average (TLV-TWA) (p<0.05), the results of risk assessment showed that, control approaches should be applied for welders specially in Full pass, Filling, Filling cap, and Back weld groups due to their medium (M) and high (H) rank of risk.

The risks of fire and explosion in oil and gas industry need to be managed. The objectives of the present study were to assess the risk of fire and explosion in Iso-max unit of Tehran Oil Refinery using Dow’s fire and explosion index and to study the influences of the controlling methods. The latest version of DOW fire and explosion index guideline was applied to calculate the fire and explosion index at process subunits of Iso-max. The important process subunits in Iso-max unit were identified based on important affecting parameters such as process pressure, temperature and material value. In next step, the important parameters affecting the fire and explosion index were identified and estimated. The fire and explosion index was calculated for each subunit. Mean time, the controlling methods for each case was identified and its influences were studied. The results revealed that, 6 subunits out of 8 studied subunits had a sever fire and explosion risk. One subunit had a heavy risk and one had an intermediate risk of fire and explosion. The separating container at high pressure was the most critical subunit of Iso-max, holding an F&E Index of 220. The reactor feeding furnace was the least dangerous subunit with an F&E Index of 122. The study showed that the application of controlling methods could reduce the F&E Index extensively.

Nowadays, in addition to implement the quality of management systems and environment management and due to the effects of safety and health issues on working processes, the organizations have also sought to acquire health and safety management systems. This descriptive –analytic and past reviewing study has been implemented based on five years (from 2006 to 2010) recorded documents and statistics information in food industrial. Information was collected based on the food industries checklists. The safety indices including risk evaluation, safety auditing, personnel safety training, investment in personal protection equipments, accident severity, accident frequency, accident frequency-severity and job decease repetition coefficient were used for determination of safety programs successfulness degree. Productivity indices such as human forces productivity, wastage amount, production per capita, personnel absence, personnel complaint and production exploitation were for organizational productivity measurements. The results showed that the safety programs implementation have positive impacts on mentioned productivity indices. So there was a direct relationship between safety rules respect and work condition optimization which arouse productivity development in the organizations. Indices definition could be helpful for the safety system effectiveness and system continuous performance optimization.

Due to the physicochemical properties of nitrogen oxides as active molecules, the removal of this group of pollutants has always been considered as a matter of concern for specialists. The present study seeks to develop the removal technique of nitrogen oxides «as a major type of air pollutant» by means of non-thermal plasma process under atmospheric conditions. Besides having the potential to reduce energy consumption in the pollutant removal process, non-thermal plasma technology also provides particular flexibility for the simultaneous removal and mitigation of the secondary pollutants. In this research we have used the Dielectric Barrier Discharge (DBD) plasma process to achieve an effective conversion of Nitrogen Oxides (NOx). As a result of the collisions between the electrons and the airflow containing NOx, active radicals and molecules are generated in a limited and controlled volume (plasma reactor) and the conversion and removal process is then carried out in the presence of hydrocarbon as reducer gas. The key factors for NOx conversion especially in the non-thermal plasma condition are the geometric structure and design of the reactor, type of discharge, type of power supply, temperature, space velocity, propane/NOx mole ratio, and voltage. In the present study, the factors of temperature, mole ratio of the reducer and input voltage were examined. The results showed that the optimal conditions for conversion of NOx into N2 and O2 are temperature of 180°C, propane/NOx mole ratio of 0. 5, and voltage of 5 KV. Under the optimal conditions acquired, NOx conversion was 0. 79 in the 100 PPM concentration. Under the conditions of the present study, 1-5 PPM Ozone, Formaldehyde, and CO was generated as the undesirable pollutants.

Musculoskeletal disorders commonly experienced by dental professionals can affect their health and well-being. The main aim of this study was to determine the prevalence of musculoskeletal disorders among dentists in Iran. A cross sectional study was carried out in Rasht, northern Iran. Participants were dental workers who completed structured questionnaire on the topic of musculoskeletal disorders related to their job. The first part of the questionnaire was self-administered regarding their demographic information and job satisfaction. The second part was the Nordic Musculoskeletal questionnaire for determining the site of pain, if any. The severity of pain was assessed by using Visual Analog Scale (VAS). The third section was RULA questionnaire (Rapid Upper Limb disorder Assessment) to determine the awkward posture during their work and eventually the need to improve the condition. A total of 92 dentists responded to the questionnaire. Seventy three percent of participant dentists had musculoskeletal pain. The common painful sites of the body were as follows: neck (43.4%), back (35.8%), and shoulder and wrist (each 25%). Direct inspection was a risk factor for neck pain (OR: 35.34, p<0.001). This study revealed a relatively high prevalence of musculoskeletal pain among dentists. The severity of pain was related to higher action level of the RULA score; indicating that dentists with higher RULA scores needed to adopt better working posture.

The school environment is a place wherein students spend one third of their life with the other students and school staff. Therefore, it is essential to pay continuous and specific attention to safety problems in schools. We identified 20 critical success factors (CSFs) in the current study based on previous researches in order to achieve effective school safety. Then these factors validated by 33 governmental high school administrators. This survey was conducted in Tehran, among 96 governmental high school administrators. The data for this survey was collected from 96 high school administrators and then we prioritized those success factors based on high school administrators'' viewpoints. ‘‘Physical safety’’ was the most influential factor for school safety in Tehran governmental high schools. The last four factors of school safety CFSs were excluded from the list. In conclusion, physical safety which is the most traditional school safety element and concerned with the physical vulnerability of the buildings at school, plays a major role in making a safe school in Tehran governmental high schools.

This study was carried out to evaluate tobacco dust concentration and also designing a suitable ventilation system for reduction of tobacco dust concentration in a tobacco processing factory in the north of Iran.Gravimetric method was used to determine the tobacco dust concentrations in the emission sources an also indoor workplace. A local exhaust ventilation system was designed according to the velocity pressure method recommended by ACGIH. Mean tobacco dust concentrations (ranged from 23.56 to 432.59 µgm-3) were higher than TLV-TWA in the proximity of all indoor emission sources where some individuals were working. However, mean indoor and outdoor tobacco dust concentrations (7.71and 0.04 µgm-3 respectively) were lower than TLV-TWA. Totally 5 separated ventilation systems and 5 centrifugal fans were designed and selcted to pull the air through 46 different hoods. Some downward slot hoods similar to VS-708 type were designed for the work-tables in tipping unit and some upward slot hoods that are similar to VS-903 type recommended by ACGIH''s industrial ventilation committee were also selected for tipping manipulation unit. Some enclosing hoods were designed for feeders. Duct velocity of 1060 mmin-1 has been selected for all systems. Total air flow rates ranged from 240-369 m3min-1. A very high efficient bag house containing several bag filters was used to collect dust. In conclusion, because of a high concentartion of tobacco dust in the proximity of sources and risk of workers exposure to tobacco dust, a suitable local exhaust ventilation system was designed to reduce particulate air pollution concentrations in a tobacco processing factory.