IL6 and asthma: Clinical and epidemiologic studies indicated that fine particles (<2.5 μm) and nanoparticles (<100 nm) from urban airborne particulate matter (PM) contributed to asthma exacerbation [11,12,13], showing an increased use of asthma medication [14], the reduction of lung function, and the increase of bronchial hyper-reactivity, as well as sputum IL-6 levels in subjects with asthma [13,15], after exposure to traffic-related air pollution.