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This paper uses observations and The Air Pollution Model (TAPM) to examine the atmospheric processes controlling air pollution dispersion for the period May 1st - August 31st 2008 in the small town of Milton, located in the southern part of New Zealand. Similar to other small towns in the region, Milton suffers from poor air quality during winter, with 43 days observed to exceed a 24-hour average PM10 concentration of 50 µgm-3 (HIGH air pollution) during the study period. Observed PM10 concentration in Milton has two air pollution peaks each day: 17:00- 1:00 NZST and 7:00 - 11:00 NZST. On HIGH air pollution days, a stable boundary layer (SBL) is typically present between 17:00 - 11:00 NZST (18 hours). The SBL reaches an average maximum depth of 150 m, with a strongly stable layer (SSL) (> 2.5 °K m-1) near the surface, which has an average depth of 25 m. Importantly, the strength and depth of the SBL and SSL in Milton is affected by the interaction of surrounding topography with gradient air flow, Modelled results compare well with observations and the performance of TAPM was found to improve using data assimilation (DA). With (without) DA, TAPM correctly predicted 58% (23%) of HIGH air pollution days. Using TAPM to assess the sensitivity of the Milton township to a range of emission scenarios suggests a 50% reduction in both industrial and domestic PM10 emissions (a total of 208 kg day-1) is required to adhere to the Air Quality National Environmental Standards (AQNES) target of one exceedance per year. [ABSTRACT FROM AUTHOR]

This paper investigates seasonal patterns and annual trends of PM10 concentrations in the small town of Mosgiel located in Otago, southern New Zealand. A second aim is to explore the relationship between PM10 concentrations and concomitant meteorological factors. PM10 data were collected intermittently over a seven-year period (1998-2004) using both gravimetric Minovol and Hivol methods. Meteorological data were gathered over the same time period from two sites in the region. Although there has been an increase in annual PM10 concentrations over the period 2001-2004, the small dataset and the high variability precludes drawing firm conclusions. Monthly PM10 levels were at their highest in the winter months of June and July on days with low minimum daily temperatures, low wind speeds and little or no rainfall. the analysis shows that, based on limited data, PM10 exceeded the new national 24-hour PM10 standard of 50µg m-3 to ten times each winter. Given more frequent sampling, it is expected the number of exceedances could be significantly higher, and the Mosgiel area is unlikely to meet the new national standard, which allows only one exceedance of the standard each year. Analysis of meteorological data shows that minimum daily temperature and logarithmically transformed average daily wind-speed and total daily rainfall are all significantly correlated with PM10 concentration, but the correlations are not strong. The study highlights the need for regional authorities to undertake continuous sampling of particulate and more detailed meteorological monitoring close tot the pollution sources in order to better understand the air pollution meteorology of this small town. [ABSTRACT FROM AUTHOR]

The composition and relative abundance of airborne pollen in urban areas of Australia and New Zealand are strongly influenced by geographical location, climate and land use. There is mounting evidence that the diversity and quality of airborne pollen is substantially modified by climate change and land-use yet there are insufficient data to project the future nature of these changes. Our study highlights the need for long-term aerobiological monitoring in Australian and New Zealand urban areas in a systematic, standardised, and sustained way, and provides a framework for targeting the most clinically significant taxa in terms of abundance, allergenic effects and public health burden. [ABSTRACT FROM AUTHOR]