Modeling the influence of environmental factors on human respiratory irritation from natural exposures to Karenia brevis aerosols

Abstract

The Coupled Natural and Human Systems program of US National Science Foundation is supporting our effort to elucidate linkages between harmful algal blooms and associated impacts on human health, society and economy of coastal communities. The human respiratory system is negatively impacted by inhaled toxic aerosols from the Florida red tide dinoflagellate, Karenia brevis. It has been hypothesized that surf height, wind speed, and wind direction were the predominant factors determining the amount of toxin reaching exposed individuals. Recent findings indicate that there are more environmental factors influencing the level of respiratory impacts from brevetoxins. We report on analyses that include additional factors such as air temperature, water temperature, dew point, barometric pressure, K. brevis cell counts, annd distance and direction from K. brevis cells to the individual. Factors contributing most to differences between no respiratory irritation and mild respiratory irritation were water temperature, air temperature, and dew point. Those factors contributing most to differences between mild respiratory irritation and moderate respiratory irritation were wind direction, surf conditions, and wind speed. Data on respiratory impacts was provided by the Beach Conditions Reporting System (BCRS). This system provides twice daily reports from lifeguards and park rangers at public beaches. These subjective reports include observed levels of respiratory irritation among beach-goers. Other environmental data were provided by a variety of local sources including private and public weather stations and many monitoring and research efforts. The resultant model provides a means to forecast respiratory impacts from observations of HAB distribution, and meteorological and oceanographic conditions.