Climate, air quality, and allergy: Emerging methods for detecting linkages

Both anthropogenic and naturally occurring air contaminants can be influenced by climate variability and change and in turn may have important implications for human health. Anthropogenic ozone (O₃) is a pollutant that poses serious health concerns and whose formation in the lower atmosphere depends on temperature and sunlight as well as other meteorologic parameters. Airborne pollens released by trees, grasses, and weeds are responsible for considerable respiratory morbidity and are also influenced by climate factors, as well as by changing carbon dioxide concentrations. Here we report recent findings from a research team in New York City (NYC) that has been investigating interactions between climate, air quality, and human health. The first case study we cover made projections of future O₃ and temperature levels at the county level in the NYC metro area under alternative climate change scenarios, and then translation of these changes into mortality impacts using exposure-response equations derived from historical data in NYC. Findings suggested that heat-related mortality could grow in importance over future decades as compared with O₃-related mortality, and that health effects could be reduced by policies that limit greenhouse gas emissions. In the second case study, we analyzed the effects of spring tree pollen peaks on sales of over-the-counter allergy medications in NYC over a 6-year period. We found a significant effect which had a maximum at lag 2, indicating that tree pollen peaks precede spikes in medication sales by approximately 2 days. Both sets of findings highlight the value of climate and health research as a tool for policy makers concerned with anticipating and preventing adverse health impacts related to climate change.