Objective To provide evidence for treatment of local pollen allergic diseases such as allergic rhinitis,allergic asthma,by defining species,amounts,dispersal variation of airborne pollen in Xi'an city. Methods Daily airborne pollen monitoring was performed by Durham gravitational method from January 1 st 2013 to December31 st 2014,and the species of pollen were identified by optical microscopic. Results A total of 27464 grains of pollen were collected in two years,which belonged to 4 families,22 genera and ...