Grantee Research Project Results

Final Report: Predicting Regional Allergy Hotspots in Future Climate Scenarios – Putting the Where & When on Wheezing

EPA Grant Number: R834359
Title: Predicting Regional Allergy Hotspots in Future Climate Scenarios – Putting the Where & When on Wheezing
Investigators: Foster, David R. , Rogers, Christine A. , Stinson, Kristina
Institution: Harvard University , University of Massachusetts - Amherst
EPA Project Officer: Chung, Serena
Project Period: September 1, 2009 through August 31, 2013 (Extended to August 31, 2014)
Project Amount: $898,634
RFA: Climate Change and Allergic Airway Disease (2008) RFA Text | Recipients Lists
Research Category: Human Health , Climate Change

Objective:

The central objective of this project was to better predict the impacts of climate change on pollen-induced allergic airway disease. We focused on the allergenic plant, common ragweed (Ambrosia artemisiifolia L.), and how its distribution, abundance, and pollen production may change in response to current and future climatic variation in the Northeast. Specifically, we: (a) conducted field observations of common ragweed presence and absence across New England and created maps of its distribution based on climate and other land cover datasets; (b) measured and compared demographic properties of common ragweed populations in Massachusetts across an urban-rural gradient; (c) collected data on concentrations of ragweed pollen by counting pollen grains captured by special air samplers installed across an urban-rural gradient; and (d) conducted a large greenhouse study to test growth and reproductive responses of ragweed plants from VT, MA, and NY to current and predicted levels of atmospheric CO₂.

We used these datasets to explore the relationships between allergenic plants and climate change, and tested the hypothesis that a populations origin will determine its response to predicted increases in atmospheric CO₂. Data from our field observations and experiments are being used in combination with geographic datasets on climate and human demographic patterns to predict the current and future distribution of ragweed, and assess specific risk factors (output, timing, and pollen potency) for ragweed allergy exposure across the region.

We evaluated the effects of environmental conditions on three pollen allergy risk factors: (i) timing of pollen production (onset, peak and duration); (ii) pollen output; and (iii) allergic potency (Amb-1 protein levels) in order to address the following questions: What is the role of climate on the production, distribution, dispersion and potency of pollen? How do climatic conditions affect growth, distribution and phenology of allergenic plant species? How will these risk factors change in future climate scenarios?

Summary/Accomplishments (Outputs/Outcomes):

Distribution of ragweed: Using data from a presence-absence survey of ragweed populations across New England and associated spatial datasets, we showed that ragweed distribution in New England is largely attributable to fine-resolution predictor variables such as mean annual temperature, mean temperature of the warmest quarter, percent impervious surfaces, and percent forest canopy.

Ecological variation in field populations: Results from a field survey of 24 populations across three climate zones in Massachusetts indicate key differences in plant size, flowering, and allometric relationships between size and flowering. Flower production appears more strongly dependent upon size in the cooler sites than in the warmer sites, suggesting that plants produce more flowers per unit of growth in warmer areas than in cooler areas. Thus, smaller urban populations may produce as much or more pollen than equal sized populations in the more rural/cooler locations. We also found population-level variation in plant size, flowering time, flower production, and population size.

Pollen cloud variation in Massachusetts: We generated a 3-year dataset from the Burkard pollen traps to provide high-resolution calendars of airborne pollen abundances across a Massachusetts urban-rural gradient. We found important differences between sites that are persistent from year to year, as well as inter-annual variation in the duration and peak of the pollen season. For example, data from years 1-2 show that peak 24-hour pollen concentrations were higher at in areas surrounded by agriculture than in those surrounded by forest or developed surfaces. Airborne pollen declines in late August, 2011 corresponded with Hurricane Irene, indicating reduced pollen output under heavy rains. This is the first dataset to demonstrate fine-scaled patterns of airborne ragweed pollen concentration.

Responses of ragweed to experimentally elevated CO₂:We found that ragweed populations from different parts of its range differ in several types of plant traits including phenology, biomass and pollen production. For example, we saw rapid flowering times and greater stimulation of phenology in the most northern latitude in the study. Although elevated carbon dioxide significantly increased the start of the flowering season and flowering duration for all populations, northern plants had a earlier start to flowering and a longer flowering season than the middle and southern populations. We also found that CO₂ growth stimulated growth and reproduction more in northern latitudes than elsewhere. Together, our findings underscore the importance of population-level differences in understanding regional pollen exposures, with hotspots identified in northern latitudes.

Conclusions:

By combining field sampling, geographic information system (GIS) analysis, and controlled experiments we have generated unique datasets to help predict when and where pollen allergies caused by common ragweed are most likely to increase in response to changes in atmospheric carbon dioxide. Specifically, we have (1) mapped common ragweed abundance as a function of regional climate patterns; (2) demonstrated landscape-level ecological variation in allergenic plant responses to environmental conditions in urban and rural ecosystems of Massachusetts; (3) documented fine-scaled landscape and temporal variation in atmospheric pollen counts across Massachusetts; and (4) provided unique data showing that not all ragweed populations within a given region are alike and will have different responses to predicted increases in levels of CO₂ in the atmosphere. Our datasets include evidence for how climate change may affect (i) timing of pollen production (onset, peak and duration); (ii) pollen output; and (iii) allergic potency (Amb-1 protein levels). We can conclude that: climate has a role on the production and distribution of pollen, and that environmental conditions differentially affect growth, distribution and phenology of allergenic plant species. As a result, we can begin to better understand ragweed allergy potential under future climate scenarios.

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Publications Views
Other project views:	All 13 publications	1 publications in selected types	All 1 journal articles

Publications
Type	Citation	Project	Document Sources
Journal Article	Stinson KA, Albertine JM, Hancock LMS, Seidler TG, Rogers CA. Northern ragweed ecotypes flower earlier and longer in response to elevated CO₂: what are you sneezing at? Oecologia 2016;182(2):587-594.	R834359 (Final)	Full-text from PubMed Abstract from PubMed Associated PubMed link Full-text: Springer-Full-text PDF Exit Abstract: Springer-Abstract & Full-text HTML Exit

Supplemental Keywords:

Common ragweed, pollen, allergy, Amb-A1 protein, RFA, Health, Air, Scientific Discipline, Health Risk Assessment, Risk Assessments, Atmosphere, Air Pollution Effects, climate change, Ecology and Ecosystems, air quality, ecosystem models, public health effects, environmental monitoring, climate models, future projections, allergens, climatic influence, global vegetation models

Relevant Websites:

https://sites.google.com/a/umass.edu/stinson/

http://harvardforest.fas.harvard.edu Exit

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.