title: Analysis of meteorologic variables and seasonal aeroallergen pollen counts in Denver, Colorado.
abstract: BACKGROUND
  The observation of low levels of weed pollens following a freeze and an early autumn snowfall in Denver, Colorado led to this analysis of meteorologic variables and pollen counts.
  
  
  OBJECTIVE
  The purpose of this study was to examine, in depth, the relationship between observed pollen counts and a selection of independent meteorologic variables.
  
  
  METHODS
  We prospectively studied in 1991 daily high and low temperature, relative humidity, precipitation, barometric pressure, percent sunshine, wind velocity and direction, tree, grass, and weed pollen, as well as dates of the first frost/freeze. Similar data were retrospectively analyzed for 1987-1990.
  
  
  RESULTS
  Correlation coefficients for the prospective data were as high as .611 for high temperature and cottonwood and .718 for high temperature and maple (P < .001). High and low temperature showed strong correlations with the combined weed counts (.598 and .628, respectively, P < .001).
  
  
  CONCLUSIONS
  Denver weed pollens appear impacted more by temperature and less by precipitation and humidity, while the converse is true for tree and grass pollen. However, weed pollen, especially sage, may appreciably rebound after freezing temperatures. While separate meteorologic variables may have high correlations with specific pollen counts in a given year, such effect is not consistent and varies from year to year.
authors.affiliation: Allergy-Immunology Service, Fitzsimons Army Medical Center, Aurora, Colorado, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Glassheim
authors.forename: R A
authors.initials: RA
authors.lastname: Ledoux
authors.forename: T R
authors.initials: TR
authors.lastname: Vaughan
authors.forename: M A
authors.initials: MA
authors.lastname: Damiano
authors.forename: D L
authors.initials: DL
authors.lastname: Goodman
authors.forename: H S
authors.initials: HS
authors.lastname: Nelson
authors.forename: R W
authors.initials: RW
authors.lastname: Weber
mesh_terms: D000485:Allergens; D011232:Chemical Precipitation; D003080:Cold Temperature; D003120:Colorado; D006109:Poaceae; D011058:Pollen; D012189:Retrospective Studies; D012621:Seasons; D014197:Trees; D014887:Weather
chemical_list: D000485:Allergens