Pollutant dispersion in a developing valley cold-air pool

Pollutants are trapped and accumulate within cold-air pools, thereby affecting air quality. A numerical model is used to quantify the role of cold-air-pooling processes in the dispersion of air pollution in a developing cold-air pool within an alpine valley under decoupled stable conditions. Results indicate that the negatively buoyant downslope flows transport and mix pollutants into the valley to depths that depend on the temperature deficit of the flow and the ambient temperature structure inside the valley. Along the slopes, pollutants are generally entrained above the cold-air pool and detrained within the cold-air pool, largely above the ground-based inversion layer. The ability of the cold-air pool to dilute pollutants is quantified. The analysis shows that the downslope flows fill the valley with air from above, which is then largely trapped within the cold-air pool, and that dilution depends on where the pollutants are emitted with respect to the positions of the top of the ground-based inversion layer and cold-air pool, and on the slope wind speeds. Over the lower part of the slopes, the cold-air-pool-averaged concentrations are proportional to the slope wind speeds where the pollutants are emitted, and diminish as the cold-air pool deepens. Pollutants emitted within the ground-based inversion layer are largely trapped there. Pollutants emitted farther up the slopes detrain within the cold-air pool above the ground-based inversion layer, although some fraction, increasing with distance from the top of the slopes, penetrates into the ground-based inversion layer.Peer reviewe

AIRWATCh: DOES IT MEASuRE PARTICLES OR WhAT? AirWatch: Does it Measure Particles or What?

ABSTRACT CSIRO's contribution to the educational and community AirWatch program included a 'filter soiling' technique for measuring airborne particle concentrations. This paper (i) describes the robust calibration process underlying the technique, (ii) shows that the technique actually measures black carbon concentrations rather than overall particulate matter concentrations, (iii) compares the results with a European black smoke calibration, demonstrating that the latter has been adjusted by a factor of two to account for organic components, an

The Australian Air Quality Forecasting System : prognostic air quality forecasting in Australia

The Australian Air Quality Forecasting System provides over 24-36 hours into the future, hourly high-resolution, numerical air quality forecasts for New South Wales and Victoria. The forecasts are updated twice daily. The System is described, and performance results are summarised. Now there are moves to extend the System throughout Australia, and to participate in the uptake of adaptations of the System internationally.6 page(s