Chemical and Molecular Characterization of Aerosols in the Caribbean During African Dust Events: Focusing on Fungal Content

African dust (AD) particles are transported to the Caribbean region every year mostly during the summer months causing an increase in the concentrations of particulate matter in the atmosphere. AD is one of the most important natural sources of mineral particulate matter at the global scale, and many investigations suggest that it has the ability to transport dust-associated biological particles through long distances. Fungal spores, a major component of primary biogenic aerosol particles, are ubiquitous in the atmosphere, and play an important role in the chemistry and physics of the atmosphere, climate, and public health. The relationship between AD incursions and the concentration of fungal spores in the Caribbean region is poorly understood. In order to have a better understanding of the effects of AD incursions on fungal spore's emissions, we used a Burkard spore trap to determine spore's concentration at the tropical montane cloud forest of Pico del Este at El Yunque National Forest (PE), Puerto Rico. Results showed that Basidiospores and Ascospores comprised the major components of the total spore's concentrations (as high as 98%) both in the presence and absence of AD. A considerably decrease (of up to 75%) in the concentration of fungal spores during AD events was observed. Aerosol samples in the presence and absence of AD were also sampled using the stacked-filter units at the UPR's atmospheric observatory of Cabezas de San Juan (CSJ), a marine site located in Fajardo, Puerto Rico; and at an urban site, Facundo Bueso (FB) building, at the University of Puerto Rico. The presence of AD was supported with satellite images of aerosol optical thickness, and with the results from the air masses backward trajectories calculated with the NOAA HYSPLIT model. Preliminary results of gravimetric analyses, ion speciation, carbonaceous content (organic and elemental carbon (OC and EC)) and molecular characterization (ergosterol content) will be presented. Additional efforts to understand the relationship between the arrival of AD to the Caribbean and a decrease in spore's concentrations are needed in order to investigate changes in local spore's vs the contribution of long-range spores transported within the AD.