The Air quality in Shiraz was assessed based on a one-week passive sampling campaign. During the first week of the summer 2003, about 400 passive samplers were used in groups of two and three, so that 187 sampling stations covered all of Shiraz. Pollutant gases including SO2, NO2 and BTX (benzene, toluene and xylene) were sampled by diffusive sampling tubes. Collected samples were analyzed and pollutant concentrations were determined by using ion chromatography, spectrophotometry and gas chromatography techniques. The result of the analysis shows that SO2 and NO2 concentrations exceed national and international standards in the central and southern parts of Shiraz. Weekly averaged concentrations of benzene, toluene and xylene at all sampling sites were 105, 206 and 123 μg/m3, which exceed national and international standards. Based on the results, more than 15% of Shiraz's population (180,000 out of 1.2 million people) were exposed to high levels of NO2 during this survey period.

Introduction: The applicability of Nanofiber (NF) membranes in Air sampling of pollutants for the purpose of determining the Airborne concentration has received little attention around the world. The present study aims to optimize the fabrication of NF membrane for the of Air sampling application. Materials and methods: The polyvinyl chloride NF membranes were fabricated using needle-based solution electrospinning technique. The experimental design was prepared by Design-Expert v7. 0 and data analysis was done by Central Composite Design (CCD) base on Response Surface Methodology (RSM) technique. The ability of the fabricated membranes in Air sampling applications was performed by sampling of Airborne crystalline silica by them using the National Institute for Occupational Safety and Health (NIOSH7602) method and then comparing with the commercial PVC membranes. Results: The fabricated NF membranes had a mean porosity of 31. 60% compared to a porosity of 25. 1% in the case of commercial Polyvinyl Chloride (PVC) membranes. The electrospun NF membranes had mean pressure drop of 194. 23 Pa, which is lower than the 204 Pa pressure drop of commercial PVC filters. The mean concentration of silica sampled by the electrospun NF membrane was 0. 14 mg/m 3 while this was 0. 03 mg/m 3 for commercial PVC membrane. The difference concentration of crystalline silica sampled by NF and commercial PVC membranes had the strongest relationship with the electrospinning solution concentration (r=-0. 785, p>0. 05). Conclusion: The NF membrane has high performance in sampling the crystalline silica dust from the Air stream compared to commercial PVC membranes.

The jarless cyclone calibration method is an appealing approach because it removes the need for calibration adapters and eliminates potential sources of error that result from poor or inconsistent seals in calibration adapters or calibration jar lids. The aim of this study was to perform a detailed review of the jarless calibration method by (1) examining the rationale behind the initial pressure drop range specified by the method and (2) evaluating the accuracy of the method in contrast to flow rate measurements in a well-controlled, jar protocol. Four types of respirable cyclones and two filter brands with samples from three separate production lots were considered as components of the sampling trains under consideration. Volumetric flow rate and pressure drop were measured under controlled conditions in a cylindrical jar designed for these determinations. The initial challenge pressure range evaluated in this study was modified based on cyclone type. The measured pressure drop fell within the modified range for all configurations considered, indicating the modified ranges were appropriate. The accuracy of the jarless method was then evaluated by comparing measured volumetric flow rates using different calibration methods for various cyclone, filter brand, and filter lot combination. The jarless method provided accurate calibration results utilizing the modified initial pressure drop ranges utilized in this study. Therefore, it is recommended the initial pressure drop range specified by the jarless method be modified to account for differences among cyclone types.

Introduction: Trichloroethylene (TCE) is an industrial solvent which is often used as a degreaser for metal parts. Due to adverse health effects and carcinogenic properties of this solvent, knowing its concentration in the workplace atmosphere is really crucial. Nowadays, carbon nanotubes with high efficiency are being used for sampling of this chemical. Method: Three types of static standard atmosphere with the concentrations of 18, 35, and 53 ppm were produced. Then, sampling tubes which contained 10 mg of functionalized multi-walled carbon nanotubes were prepared. Subsequently, Air standard atmosphere was made inside sampling bags. The mean adsorption efficiency was examined in three sampling flows (0. 1, 0. 15, and 0. 2 L/minute). Finally, desorption was performed by carbon disulfide and analysis was conducted using gas chromatography coupled to mass spectrometry) GC/MS (according to the instructions of NIOSH 1022 and OSHA 1001. Results: The highest amount of adsorption occurred in the flow of 0. 1 L/minute (81. 51± 3. 72). Furthermore, considering the three studied concentrations of trichloroethylene (18, 35, and 53 ppm); the highest efficiency was recorded at 18 ppm concentration (83. 18± 11. 67). The highest adsorption efficiency with the lowest standard deviation (80. 55± 3. 85) was observed in samples that were immediately injected into the GC/MS machine. Conclusion: Given that time-lapse had no significant effect on adsorption efficiency, it is argued that the pollutant had suitable stability on the surface of the adsorbent. The results of this study show that multi-walled carbon nanotubes have better performance at lower concentrations of trichloroethylene.