Long-term Measurements of Carbonaceous Aerosols in the Caribbean Region

Carbonaceous aerosols (i.e., those composed of organic carbon and elemental carbon) play an important role in the Earth's chemistry-climate system, air quality, and public health due to their small particle sizes (< 1 µm) and strong light-absorbing and scattering properties. The tropics contribute significantly to the global radiative balance partly because of influences from carbonaceous aerosols, which have both natural and anthropogenic sources. There is not much information of the properties of total carbon (TC) fraction in terms of their characterization in natural and polluted environments. Therefore, it is required further investigation to quantify their true extend and implications over the Caribbean with an extensive, long-term study in which in-situ measurements can be taken at different sites, representative of the multiple tropical environments. Aerosol samples collected on tandem quartz filters were analyzed using the thermal-optical analyzer to correct the over estimation of particulate OC (positive artifact) that occurs during the sampling. Mass concentrations of TC during summer (mean 0.06 µg m^-3) were less than those in winter (mean 0.25 µg m^-3). Samples collected during African dust events showed lower TC mass concentrations (mean 0.13 µg m^-3) than those collected with absence of African dust (0.27 mean µg m^-3). Moreover, samples were classified according to the origin of their air masses to provide a better insight on the possible sources of the carbonaceous aerosols. These results will provide a baseline for seasonal OC and EC aerosol mass concentration in Puerto Rico.