Ultrastructural Nasal Pathology in Children Chronically and Sequentially Exposed to Air Pollutants

Southwest Metropolitan Mexico City (SWMMC) children are repeatedly exposed to a complex mixture of air pollutants, including ozone, particulate matter, and aldehydes. Nasal biopsies taken from these children exhibit a wide range of histopathologic alterations: marked changes in ciliated and goblet cell populations, basal cell hyperplasia, squamous metaplasia, and mild dysplasias. We studied the ultrastructural features of 15 nasal biopsies obtained from clinically healthy children 4 to 15 yr of age, growing up in SWMMC. The results were compared with nasal biopsies from 11 children growing up in Veracruz and exposed to low pollutant levels. Ultrathin sections of nasal biopsies revealed an unremarkable mucociliary epithelium in control children, whereas SWMMC children showed an epithelium comprised of variable numbers of basal, ciliated, goblet, and squamous metaplastic as well as intermediate cells. Nascent ciliated cells, as evidenced by the presence of migratory kinetosomes, were common, as were ciliary...