Print PageChildren in urban areas have high rates of allergies and asthma, and there is strong evidence that pollen exposure is a contributing factor. Much of this pollen is produced locally by herbaceous plants, which also produces more allergenic pollen when grown in high temperatures and carbon dioxide concentrations, which occur in cities. However, the local sources of allergenic pollen in urban areas remains poorly characterized, as does the extent of spatial heterogeneity in pollen concentrations. For this project we investigated whether allergenic pollen concentrations are higher in areas with certain land uses, such as vacant lots. Then we examined whether more vacant lots have more allergenic pollen in the air.
In order to determine allergenic pollen concentrations in different land uses, we worked with students from Western International High School in Detroit. Detroit has the highest proportion of vacant lots in the nation, allowing us to collect pollen samples from a variety of land uses. To collect pollen, students placed homemade Durham gravitational pollen collectors in a variety of different areas around the school and in their own neighborhoods. Pollen collectors were left outside for four days, collected, and brought back to the University of Michigan, where we identified a sub-sample of pollen grains. Our student collaborators also visited the University of Michigan and participated in various activities on campus.
Results/Conclusions
We found a high degree of spatial heterogeneity in pollen concentrations but still observed correlations between pollen concentrations, land use, and local plant abundance. This corroborates anecdotal observations that many of the most allergenic species (e.g. members of the Ambrosia genus) are most abundant in vacant lots. Our work also has policy implications by showing some of the public health risks associated with vacant lots. The importance of these results will only increase over the next several decades, as climate change increases the quantity and allergenicity of pollen in urban areas via rising carbon dioxide concentrations and temperatures.
This research would not have been possible without the help of the high school students. Moreover, working with these students allowed us to accomplish our broader goal of using a hands-on project to educate students about the ecology of the urban environment, and its direct link to everyday life. Working in Detroit also allowed us to introduce ecology to an underrepresented group and to reap the benefits of collaborating with a secondary education institution.
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