As main air pollutants, volatile organic compounds (VOCs) must be paid special attention. In this study, the removal efficiency of xylene from the air was investigated by nano-activated carbons (NACs) as an efficient adsorbent and compared to commercial activated carbons (ACs). In the chamber, the xylene vapor in pure air was generated, stored in the airbag (5 Li), and moved to adsorbents. Then, the xylene vapor was absorbed on the NAC/AC adsorbents and desorbed from it by a heat accessory. The efficiency of xylene removal with NACs and ACs was investigated in the dynamic and static systems based on 100-700 mg L-1 of xylene, flow rates of 100 ml min-1, and 100 mg of adsorbent at a humidity of 32% (25°C). Xylene concentrations were determined by gas chromatography equipped with a flame ionization detector (GC-FID).  In the batch system, the maximum absorption capacity for NACs and ACs was obtained at 205.2 mg g-1 and 116.8 mg g-1, respectively. The mean adsorption efficiency for NACs and ACs adsorbents was obtained at 98.5% and 76.55%, respectively. The RSD% for NACs ranged between 1.1-2.5% in optimized conditions. The characterizations of the NACs adsorbent showed that the particle-size range was between 35-100 nm.

Background:Bakery workers, Beacause of their nature, are at risk of musculoskeletal disorders caused by ergonomic factors. The purpose of this study was to evaluate the biomechanical risk factors for musculoskeletal disorders in bakery workers. Methods: In the current study, all tasks of sangak, taftoon, and lavash bakery in Gonabad were selected based on the census method. Next, Hierarchical Task Analysis (HTA) method was used for task analysis, and the job was degraded to tasks, actions, and movements. For the following step, the ART and OCRA method was implemented to identify common risk factors in repetitive tasks that can contribute to developing musculoskeletal disorders of upper limbs. Analysis of the results in this study was performed using SPSS 17. Results: According to the results study, the ART and OCRA index score for shater and chonegir tasks for all three kinds of bakeries is at high risk (red zone). In ART index score of arm movements, repetition, force, head/neck posture, and back posture for shater and choonegir task in lavash and taftoon bakery and shater task in sangak bakery is in its maximum levels. This reflects the level of red risk and indicates that in these tasks, fast arm movements, repetition, force, head/neck posture, and back posture are recognized as major occupational risk factors in these tasks. Conclusion: The results showed that the risk of musculoskeletal disorders owing to repetitive tasks is relatively high in the bakery and ergonomic interventions are required to redesign the job. This study shows the use of the ART method as a practical, applicable, easy, and convenient method for evaluation and ergonomics interventions in repetitive work tasks.