الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Carbon black is a very fine powdered form of elemental carbon and is manufactured by the pyrolysis of liquid or gaseous hydrocarbons.
Carbon black has so many applications as being a reinforcing agent in tires and rubber products, it provides pigmentation and ultraviolet stabilization in coatings, and acts as a conductive agent in electrostatic discharge compounds. Thus, millions of workers are exposed to carbon black dust either during the production process or in many different industries and under a wide range of circumstances.
Researches assessing the impact of carbon block exposure on the respiratory system of workers showed contradictory results. Some studies reported pneumoconsis, reduced lung function, emphysema and chronic bronchitis in carbon black exposed workers. In other studies respiratory impairment was not detected. Interpretation of the studies was complicated by the lack of exposure information (production process, air borne concentration of carbon black, duration of exposure, and particle size) small study population size, lack of information regarding smoking history and other occupational exposures. Hence, this study was conducted to reveal the potential respiratory effects following long term exposure to furnace carbon black.
The strategy selected for this study was the retrospective cohort approach, where data were derived from medical records of workers in a carbon black factory in Alexandria. Health status of carbon black workers was assessed periodically by the Occupational Medicine medical team of the Alexandria Faculty of Medicine, and the validity of this study was sustained by the completeness and accuracy of the medical records for the carbon black exposed and unexposed workers, as the workers´ examination and evaluation were conducted by the same medical team and by using the same tools.
In this study for respiratory assessment and to detect the presence of respiratory symptoms, chronic bronchitis and asthma among carbon black exposed workers and their controls, medical records of all workers (n=370) exposed to carbon black in the studied carbon black factory were revised, of these records 315 were selected for workers who had undergone periodic examinations since the year 2000 till 2010,and fulfilled the inclusion criteriae.
Records of a group of manual workers (300) from the Alexandria Main University hospital who were not exposed to any respiratory hazardous materials in their work environment were selected randomly and served as the comparison group.
All workers were subjected to:
- An interview which was designed based on the MRC questionnaire, only minor modification to some questions were done to adjust to the Egyptian workers.
- General medical examination and local examination of the chest.
- Spirometric measurements by means of a computerized flow volume spirometer, which can produce both volume time and flow volume curves. Lung function indices recorded were the VC, FVC, FEV1, FEV1%, PEFR, FEF 75%, FEF50% and FEF25% and percent predicted values of different lung function indices were calculated according to prediction equation of lung function for male manual workers published by the European community for steal and coal.