The atmospheric concentration of NO2 in Lima, Peru was measured through 1 year using passive samplers. The concentration was stable and evident seasonal change was not observed. Also, the distribution of NO2 concentration in entire Lima was monitored twice in different seasons. The average NO2 concentrations at 33 and 27 sites of these monitoring were 17.1 and 15.3 ppb, respectively. NO2 distribution was high in the downtown area and decreased gradually with distance from there. The wind that almost always blew from the ocean had a great influence on it. High NO2 level and the change of CO concentration suggest that the residential area in the northeast side forms a topological channel among hills to blow out the pollutants from the downtown area.