Polychlorinated dibenzo-p-dioxin and dibenzofuran in urban air of an Andean city

Abstract

Particle-bound polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in ambient air were monitored together with particulate matter less than 10 μm (PM(10)) at three sampling sites of the Andean city of Manizales, Colombia; during September 2009 and July 2010. PCDD/Fs ambient air emissions ranged from 1 fg WHO-TEQ m(-3) to 52 fg WHO-TEQ m(-3) in particulate fraction. The PM(10) concentrations ranged from 23 μg m(-3) to 54 μg m(-3). Concentrations of PM(10) and PCDD/Fs in ambient air observed for Manizales - a medium sized city with a population of 380,000 - were comparable to concentrations in larger cities. The highest concentrations of PCDD/Fs and PM(10) found in this study were determined at the central zone of the city, characterized by public transportation density, where diesel as principal fuel is used. In addition, hypothetical gas fractions of PCDD/Fs were calculated from theoretical K(p) data. Congener profiles of PCDD/Fs exhibited ratios associated with different combustion sources at the different sampling locations, ranging from steel recycling to gasoline and diesel engines. Taking into account particle and gas hypothetical fraction of PCDD/Fs, Manizales exhibited values of PCDD/Fs equivalent to rural and urban-industrial sites in the southeast and center of the city respectively. Poor correlation of PCDDs with PM(10) (r=-0.55 and r=0.52) suggests ambient air PCDDs were derived from various combustion sources. Stronger correlation was observed of PCDFs with PM(10). Poor correlation between precipitation and reduced PM(10) concentration in ambient air (r=-0.45) suggested low PM(10) removal by rainfall.