Objective: To define if exposure to environment pollution in Mexico City causes histopathological nasal mucousa changes; if so, to describe which is the most frequently histologic alteration. Method: Research made by performing biopsies in 33 adults in the inferior turbinate, residing on the northwest of Mexico City. Age range: 15 to 50 years old. The research was divided into two groups: 1. Fifteen patients exposed to pollution environment during 10.5 + 0.3 hours at day. 2. Eighteen patients not exposed. Result: There were histopathologic changes in all patients predominating chronic inflammation and squamous cell metaplasia in both groups. Conclusions: The exposed time to the environment pollution gave no significative statistic differences in the histopathologic discoveries between the two groups. Environment pollution exposure develops histopathologic changes in the nasal mucosa.