Influence of environmental conditions on carbonaceous particle concentrations within New Zealand

Variables that influence ambient concentrations of air particulate matter due to motor vehicle emissions and biomass burning for home heating were investigated for 10 urban environments in New Zealand. It was found that contributions to ambient particulate matter concentrations from these two main anthropogenic carbonaceous sources were only sometimes correlated with the population and/or source activity within an airshed. The average particulate concentration attributed to motor vehicle emissions was found to correlate with the airshed population, whereas the home heating contribution was observed to be independent. It was found that particulate matter from biomass burning for home heating emissions often build up during cold calm nights under temperature inversion conditions, restricting vertical dispersion thus confining air particulate matter to a limited atmospheric volume. The average winter particulate concentrations due to home heating within the airsheds studied were attributed more to environmental confinement rather than source activity.