respiratory symptoms and lung functional impairments associated with occupational exposure to asphalt fumes

background:  controversy exists as to the potential of asphalt fumes to induce respiratory symptoms and lung functional impairments. objective: to examine the respiratory effects, if any, of occupational inhalation exposure to asphalt fumes. methods:  in this cross-sectional study, 74 asphalt workers and 110 unexposed employees were investigated. the prevalence of respiratory symptoms among subjects was investigated by a standard questionnaire. additionally, the parameters of pulmonary function were measured both, prior to exposure and at the end of work-shift. furthermore, to assess the extent to which workers were exposed to asphalt fumes, total particulate and the benzene-soluble fraction were measured in different worksites. results:  the mean levels of exposure to total particulate and benzene-soluble fraction in asphalt fumes were estimated to be 0.9 (sd 0.2) and 0.3 (sd 0.1) mg/m 3 , respectively. mean values of fev 1 , both prior to the exposure (89.58% [sd 18.69%] predicted value) and at the end of shift (85.38% [sd 19.4%]), were significantly (p<0.05) smaller than those of the comparison subjects (93.88% [sd 13.93%]). similarly, pre-shift (87.05 [sd 8.57]) and postexposure (89.95 [sd 6.85]) fev 1 /fvc ratio were both significantly (p<0.01) lower than those of the unexposed employees (107.56 [sd 9.64]). moreover, the prevalence of respiratory symptoms such as cough and wheezing in exposed employees were 41% and 42%, respectively. the corresponding values for comparison subjects were 10.0% and 3.6%, respectively (p<0.001). the pattern of changes in parameters of lung function in asphalt workers was consistent with that of chronic obstructive lung disease. conclusion:  significant decrements in the parameters of pulmonary function as well as, a significant increase in the prevalence of respiratory symptoms in asphalt paving workers compared to their unexposed counterparts provided evidence in favor of a significant association between exposure to asphalt fumes and lung function impairments.