Influence of meteorology and source variation on airborne PM10 levels in a high relief tropical Andean city

Abstract

Atmospheric particulate matter (PM10) was evaluated with meteorology, mixing height and source variation over a two year period (January 2010 to December 2012) in the densely populated tropical Andean city of Manizales. The highest levels of PM10 were observed in areas with the highest vehicular density with values in a range of 18 - 69 µg m-3. PM10 concentrations were influenced by meteorological parameters, positively associated with temperature (r = 0.40), and negatively associated with relative humidity (r = -0.47) and precipitation (r = -0.38). The effects of scavenging by precipitation were observed by analyzing PM10 concentrations for dry periods versus wet periods. The high sulfate PM10 ionic contents observed throughout the city were consistent with the influence of public transport and automobiles, which use diesel and gasoline as principal fuels, and are recognized as the main source of particulate matter emissions. Increasing midday mixing height over downtown of the city (from 900 m to 1600 m) effectively diluted peak hour emission from vehicular traffic, as observed over a 24 hour sampling period with 30 second intervals. These preliminary data suggest factors important to modeling PM10 in high rainfall and densely populated tropical mountain ecosystems.

Keywords

• PM10
• meteorological variables
• scavenging
• mid-sized Andean cities