Saharan dust, climate variability, and asthma in Grenada, the Caribbean

Saharan dust is transported across the Atlantic and interacts with the Caribbean seasonal climatic conditions, becoming respirable and contributing to asthma presentments at the emergency department. This study investigated the relationships among dust, climatic variables, and asthma-related visits to the emergency room in Grenada. All asthma visits to the emergency room (n = 4411) over 5 years (2001-2005) were compared to the dust cover and climatic variables for the corresponding period. Variation in asthma was associated with change in dust concentration (R(2) = 0.036, p < 0.001), asthma was positively correlated with rainfall (R(2) = 0.055, p < 0.001), and rainfall was correlated with dust (R(2) = 0.070, p = 0.003). Despite the similarities and the short distance between Trinidad, Barbados, and Grenada, they have markedly different geographies, cultures, population sizes, industrialization level, and economies. Therefore, different than from the studies in Trinidad and Barbados, Grenada is a non-industrialized low-income small island without major industrialized air pollution addition; asthma visits were inversely related to mean sea level pressure (R(2) = 0.123, p = 0.006) and positively correlated with relative humidity (R(2) = 0.593, p = 0.85). Saharan dust in conjunction with seasonal humidity allows for inhalable particulate matter that exacerbates asthma among residents in the Caribbean island of Grenada. These findings contribute evidence suggesting a broader public health impact from Saharan dust. Thus, this research may inform strategic planning of resource allocation among the Caribbean public health agencies.