Temporal and spatial variability of particle-bound polycyclic aromatic hydrocabons in Bogota, Colombia

We have assessed diurnal profiles of particle-bound polycyclic aromatic hydrocarbons (pPAHs) in Bogota, Colombia using photoelectric aerosol sensors (PAS). PAS instruments were located close to a congested avenue to assess exposure to pedestrians, bike riders, drivers, and passengers. PAS signals during weekdays were significantly larger than during weekends, observing a similar pattern to traffic. During two different periods of analysis, it was found that meteorological conditions drive differences in PAS concentrations. An aethalometer was collocated with one PAS device to observe the relationship between PAS signals and black carbon (BC) concentration. We found a significant correlation between PAS signals and BC, suggesting that pPAHs and BC are products of the same source. Two PAS devices were located at different heights to assess vertical dispersion of pollutants. Our results suggest that pPAH loadings may diminish with height possibly due to a street canyon effect in the area. An assessment of exposure indicates that during rush hours, people are exposed to particulate matter enriched with pPAHs emitted from mobile sources. Measures should be implemented to reduce emission from vehicles on the road in order to protect public health.