Pollen in the atmosphere of Mexico City and its impact on the health of the pediatric population

Over a period of eight years, were assessed the main types of airborne pollen in Mexico City (a tropical region). We established the airborne pollen calendar and we evaluated the associations between aeroallergens and allergic diseases in children treated at hospitals. A Hirst-type volumetric spore trap was placed in an open area within the Chapultepec Forest, and pollen records were obtained during the flowering period of the plants. A total of 502 patients between 1 and 17 years old were evaluated. The patients were diagnosed by skin testing with extracts of tree pollen, grass and weeds. During the monitoring period, the airborne pollen grains were dominated by trees (Fraxinus, Cupressaceae, Alnus, Quercus) followed by Poaceae, with the highest average values detected between January and February. Children with positive reactions to pollen aeroallergens were diagnosed with allergic diseases. The predominant airborne allergens were determined. An airborne pollen calendar was established. A close association was found between the most frequent and abundant pollen types and the responses of children produced by exposure to pollen grains. Children with positive reactions to pollen were diagnosed with allergic conjunctivitis, allergic rhinitis, asthma and keratoconjunctivitis.