Histopathologic changes of the nasal mucosa in southwest Metropolitan Mexico City inhabitants.

Metropolitan Mexico City (MMC) is one of the most polluted urban areas in the world. The authors characterized the morphologic nasal mucosal changes in short-term (less than 30 days) and long-term (more than 60 days) exposures to the polluted southwest MMC atmosphere with high levels of ozone and other contaminants versus a control group of subjects living in a nonpolluted, low-ozone Mexican port. Seventy-six inferior turbinate biopsies were examined. The control group showed normal mucociliary epithelium, whereas the short-exposure group displayed loss of normal epithelium, basal cell hyperplasia, and mild dysplasia (17.64%). In the long-term exposure group, 78.72% of dysplasias were found (59.45% mild and 40.54% moderate) together with severe loss of normal respiratory epithelium, prominent basal cell hyperplasia, squamous metaplasia, and submucosal vascular proliferation. Our findings suggest that southwest metropolitan Mexico City inhabitants develop histopathologic changes in their nasal mucosa on exposure to the polluted city atmosphere.