Lagrangian particle dispersion simulations in cases of sea-breeze convergence

The impact of sea-breeze convergence on air quality in an area of complex coastlines and orography in northern New Zealand is investigated. Results of simulations using a mesoscale model and a Lagrangian particle dispersion model for an idealised case are described. These show that the convergence zones limit the exchange of air between opposing circulations while providing a means of elevating near-surface pollution. This provides a mechanism for transport of relatively polluted air many kilometers from the original source with potential for re-mixing to the surface the following day.