Bronchial asthma is regarded as an allergic inflammation of the airways. Air pollutants have been shown to enhance allergic responses and previous studies have demonstrated that air pollutant stimulate airway epithelial cells to produce various cytokines including inerleukin-8. Broncho alveolar lavage will be done to asthmatic patients to assess the level of interleukin 8 as a biomarker of air pollution trying to find a correlation between the level of the interleukin 8 and the spirometric parameters of the study group. There is a correlation between the level of interleukin-8 and the decreased FEV1 and FEV1/FVC parameter of the study group. The more the increase in the level of the interleukin-8 the less the value of FEV1 FEV1/FVC measured for the study group. There was a significant negative relation of between the levels of IL-8 and the FEV1 were the p value was 0.006. There was a significant negative relation between the levels of IL-8 and the values of FEV1/FVC were the P values was 0.000. Air pollution is an exacerbating factor for asthma as detected by increased level of its biomarker (interleukin-8) in the lavage of the asthmatics.