Description
Air pollution is the introduction of chemicals, particulates and biological matter into the atmosphere. Particulate matter with a diameter equal to or less than 2.5 micrometers, PM2.5, is a major constituent of air pollution and is associated with an increased risk in cardiopulmonary morbidity and mortality. Like many developing countries with increasing urbanization and population growth, Chile is burdened with air pollution complications. In addition to its increasing emissions, the climate and geography provide unfavorable conditions for the dilution of air pollutants. In this study, the ambient particulate matter and carbon mass concentrations were quantified across three sampling sites within the city of Santiago. The sites included a downtown traffic hotspot, Republica, and two residential areas: Vitacura and Las Condes. MiniVols, DustTrak DRXs, Microaetholometers and a Harvard Impactor were used to measure 24-hour concentrations of PM_._ and black carbon concentrations for 26 days during the 2013 winter season. Subsequently, gravimetric filters were weighed to determine mass concentration of PM_._ and analyzed for elemental carbon (EC) and organic carbon (OC). The mean mass concentrations of PM_._ were 59 +/- 5 _g/m_, 37 +/- 6 _g/m_ and 40 +/- 5 _g/m_ for Republica, Vitacura, and Las Condes, respectively. Mean mass concentrations of black carbon were 7.8 +/- 0.6 _g/m_, 5.4 +/- 0.5 _g/m_ and 3.9 +/- 0.3 _g/m_, respectively. Analysis of OC-EC resulted in mean organic carbon concentrations of 15.3 +/- 1.4 _g/m_, 7.8 +/- 0.8 _g/m3 and 13.8 +/- 1.5 _g/m3 in Republica, Las Condes and Vitacura, respectively. And 6.4 +/- 0.6 _g/m_, 2.2 +/- 0.3 _g/m_ and 3.05 +/- 0.5 _g/m_ for elemental carbon, respectively. PM_._ results seem to be higher than other urban cities like São Paul, Brazil and some U.S. cities, including Los Angeles, CA during the winter season. Overall results suggest that mass concentration levels of PM_._ exceed the WHO 24-hr guideline (25 _g/m_) and Chilean MINSAL 24-hr standard (50 _g/m_) for the majority of the sampling period. Seasonal impacts of frequent thermal inversion layers and decreased wind activity are influencing contributors to elevated air pollution levels. Further chemical analyses are required to assess direct sources of emissions.
