Contribution of Natural and Anthropogenic Emissions to Smog in Bogotá

Abstract:

Bogotá Colombia is an emerging mega-city whose geographic orientation creates an interesting dynamic between regional biogenic and local anthropogenic emissions. Bogotá's metropolitan area has over 13 million inhabitants all above 2,600 meters, where the anthropogenic emissions are concentrated. Because of the high elevation, density of development, and low temperatures, the local biogenic emissions are relatively small contributors to the total VOC. The surrounding area has a much lower altitude and over 5 times higher average biogenic emission fluxes. This work characterizes the interaction between local anthropogenic emissions and surrounding biogenic emissions.

The simulated photochemical environment shows clear urban/rural interfaces. Ozone concentrations are higher in the surrounding region and show titration around the boundary of Bogotá. We use chemical indicators to define the identify the extent of interaction and apportion ozone and photochemically produced secondary aerosols. We also examine the roles of proposed regulation on interaction between biogenic and anthropogenic emissions.

In Bogotá local and regional emissions exert clearly distinct influences, but also interesting confluences. The combination of regional biogenic emissions and local anthropogenic emissions creates an ideal case study for biogenic/anthropogenic interaction. Our results show strong NOx inhibition now that must be considered in the future. We also show that secondary aerosols from biogenic sources are also inhibited in our modeling system.