Perchloroethylene, the most widely used solvent in dry cleaning, is toxic to the liver, kidneys and central nervous system and may be a human carcinogen. An exposure assessment was carried out in 69 dry-cleaning shops using perchloroethylene in Tehran city, Iran. The 8-h time weighted average (TWA) breathing zone air samples and end-exhaled air samples were obtained from 179 workers who worked ...

the effect of three levels of eucalyptus leaf (0, 28.65 or 57.37mg/200mg substrate), which were either oven, freeze or air dried on in vitro ruminal fermentation characteristics was assessed. the studied parameters were in vitro gas production (ivgp), methane production, ammonia (nh3-n) concentration, in vitro organic matter degradability, partitioning factor (pf) (ratio of substrate truly degr...

The interface-selective second harmonic generation (SHG) nonlinear optical spectroscopy and the surface tension method have been used to measure the effect of electrolyte on the adsorption isotherm of 4-hydroxyacetophenone (4-HA) at the air-solution interface. It was observed that high NaCl concentration favors adsorption of organic molecules to the air-solution interface. Measurements of the p...

laboratory scale experiments were performed to evaluate the feasibility of biofilters for the removal of h2 s from wastewater treatment plant waste air. the effects of changes in air flow rate and contaminant concentration on biofilter performance treating h 2 s odours were also assessed. compost was used as media in biofilter. the study was carried out in six different phases, by increasing h2...

Background: Air pollution and concerns about health impacts have been raised in metropolitan cities like Tehran. Trend and prediction of air pollutants can show the effectiveness of strategies for the management and control of air pollution. Artificial neural network (ANN) technique is widely used as a reliable method for modeling of air pollutants in urban areas. Therefore, the aim of current ...

Air may be dehumidified when it is brought into contact with a suitable liquid desiccant. Different types of liquid desiccants are available in the market and the application of the proper desiccant in hot humid climates would improve the dehumidification effectiveness. The driving potential for a dehumidification process is the difference in the pressure of the water vapor in the air and the w...

objective: there are many communities at risk by a series of air pollution episodes. tehran is one of the most polluted cities in the world. the presence of one or more air pollutants with a certain concentration in a particular period of time can cause several adverse effects on human and animals’ well-being that can cause much morbidity. there are several pollutants in the air but some of the...

introduction: hydrogen fluoride is one of the materials which is widely used in making glass, cleaning  silicon, manufacturing florescent lamps, ceramics and also in separating uranium isotopes. on the other hand, exposure to this substance could cause health problems including eye, nose, throat and mucus membranes irritation. this study examines the relationship between fluoride (f) in the uri...