A black carbon study for the Maltese islands

Abstract

Black carbon (BC) is a component of soot which is mainly produced from the incomplete combustion of fossil fuels, bio-fuels and biomass. The main sources in our islands are mobile vehicles mostly diesel engines. Black carbon is a defined term describing the carbon as measured by light absorption. Several studies performed under the supervision of the World Health Organization recognized that the black carbon levels in particulate matter PM25 are an indicator of combustion-related air pollution which evidences the association of cardiopulmonary morbidity and mortality with BC exposure. In fact these studies show that BC content in PM2.5 or PM10 is a more robust indicator than just the levels of PM2.5 and PM10 found in air. Studies suggest that health related issues are not a direct cause of BC but it acts as a universal carrier of other chemicals which are toxic for the human body mostly the lungs, the defense cells and blood circulation. Reviews provide very good evidence that short term health effects are associated with short term exposure to BC, while cohort studies also provide sufficient evidence associating all cause and cardiopulmonary mortality with longer BC exposure. On a second note, black carbon is a powerful aerosol and is possibly the second most climate forcing factor after carbon dioxide. However, differently from carbon dioxide, black carbon remains in the atmosphere only for a number of days.