Concentration of airborne cypress pollen in Beijing city with Burkard sampler

Objective To study and classify the concentration of airborne cypress pollen in Beijing city. Methods Senven-day Burkard volumetric strap was used for sampling airborne pollen from 1st,March to 30th,April.Twenty-two hay fever patients who were only allergic to cypress pollen were asked to report their symptoms and the medical treatment.Results Cypress pollen season in 2007 was from March 14 to April 12.During the last ten days of March,the highest concentration of cypress pollen was 294g/m3/day and the average concentration was 81g/m3/day.Concentration of cypress pollen was related with the severity of symptoms with a Spearman's coefficient correlation of 0.804,(P0.001).The clas-sification of the cypress pollen concentration was 0≤6 g/m3,Ⅰ≥7 g/m3,Ⅱ≥16 g/m3,and Ⅲ≥67 g/m3.Conclusion It was the first time to monitor the concentration of cypress pollen with Burkard sampler in Beijing city. The cypress airborne pollen season lasted about 4 weeks,and the last ten days of March was the dangerous time for the patients allergic to cypress.