Development of a circuit model to describe the advection-diffusion equation for air pollution

A circuit model for calculating pollutant concentration from an area source is derived. This model includes various loss, production and transfer terms and can be used by grid modellers seeking to build a more sophisticated description of the PBL. After analysis of exchange/removal processes operating in the PBL by using the circuit model, we find that the near ground steady-state concentration is close to max(q0l/2ule, Cb) where q0 is emission rate, l the length of an area source, u wind speed, le an effective mixing length, and Cb upwind concentration. The value of q0l/2ule increases proportionally with the length of an area source and inversely with wind speed until it reaches q0/Vd during rainless time and q0/Λle during raining time. Vd is dry deposition rate, and A scavenging coefficient. The worst air quality occurs under stable atmosphere with low wind speed and rainless conditions. However, it might take more than a day to reach such a high concentration in a stable atmosphere.