in order to assess the effect of prolonged inhalation of polluted ambient air on the respiratory tract , 30 sprague-dawley rats were kept in facilities built close to a street with heavy traffic in the city of yokohama for 18 months in an atmosphere of either filtered ( filtered group ) or non-filtered polluted ambient air ( exposed group ) , and the histology of the lung was examined .
C0035237
respiratory tract
C0024109
lung