Cedar fever in Austin: Juniperus ashei plant distributions and airborne pollen
PILOT SAMPLING - JANUARY 2019
PILOT SAMPLING - JANUARY 2019
Pollen allergies afflict over 26 million Americans but predictions of airborne pollen concentrations and exposures are made at the regional scale instead of for individuals. This is partly because pollen concentrations are widely assumed to be homogenous across municipal spatial scales. In cases where pollen concentrations do vary within cities, finer grain estimates could help people avoid pollen and better manage their medications while also quantifying how local plant management can reduce pollen exposures. Creating more sophisticated predictions will require information first on how pollen concentrations vary within cities and second on plant distributions, pollen production, pollen release, and atmospheric dispersion dynamics.
Ashe juniper (Juniperus ashei) is one of the most important allergenic pollen producing plants in the United States and the cause of “cedar fever.” In this pilot study, airborne pollen concentrations were measured and compared with juniper distributions in Austin, TX. Pollen concentrations were measured simultaneously over 24 hours at 12 sites in Austin using custom-made rotorod samplers (Fig. 1A) and pollen grains were identified with microscopy (Fig. 1B). Data on Ashe juniper distributions within Austin (Fig. 2A) were obtained by request from the Urban Forest Inventory and Analysis, US Forest Service. Similar data are being collected nationally, but are not expected to be made available for several years; Austin was the prototype for this new program and this is the first time the survey data have been provided externally. One limitation of these data is that plot coordinates have been fuzzed by up to 1 km to maintain plot location confidentiality.
Ashe juniper (Juniperus ashei) is one of the most important allergenic pollen producing plants in the United States and the cause of “cedar fever.” In this pilot study, airborne pollen concentrations were measured and compared with juniper distributions in Austin, TX. Pollen concentrations were measured simultaneously over 24 hours at 12 sites in Austin using custom-made rotorod samplers (Fig. 1A) and pollen grains were identified with microscopy (Fig. 1B). Data on Ashe juniper distributions within Austin (Fig. 2A) were obtained by request from the Urban Forest Inventory and Analysis, US Forest Service. Similar data are being collected nationally, but are not expected to be made available for several years; Austin was the prototype for this new program and this is the first time the survey data have been provided externally. One limitation of these data is that plot coordinates have been fuzzed by up to 1 km to maintain plot location confidentiality.
Juniper plants were most abundant in West and Southwest Austin (Fig. 2A); these areas also had the highest recorded airborne pollen concentrations (Fig. 2B). During the sampling period, winds were predominently from the west and wind speed was generally low (< 7 mph).
The pilot data demonstrates that juniper pollen concentrations can vary substantially within Austin, and airborne pollen concentrations appeared to match broader patterns of plant abundance. However, this pilot data only includes 24 hours of sampling and does not answer how or whether these spatial patterns vary over time. Additional sampling would be required before these spatial patterns could be used to inform exposure estimates.
