Report: TR 2005/54

Author: Emily Wilton, Environet Ltd

Abstract

Concentrations of PM₁₀ measured at Hamilton, Tokoroa, Te Kuiti and Taupo generally exceed the National and Regional Air Quality Guideline for PM₁₀ of 50 µg m^-3 (24-hour average) most years during the winter months.

Tokoroa typically experiences the worst air pollution, with PM₁₀ breaches occurring between 15 and 41 occasions per year. The maximum measured PM₁₀ concentration in Tokoroa (97 µg m^-3) is also higher than in the other urban areas. Taupo, Te Kuiti and Hamilton generally record fewer breaches (typically 0-12 per location) with maximum concentrations between 60 and 70 µg m^-3. Concentrations of PM₁₀ in Tokoroa also exceed the national annual average guideline for PM₁₀ of 20 µg m^-3. All locations also fail to meet the National Environmental Standard (NES) for PM₁₀ that allows for one exceedance per year of 50 µg m^-3 (24-hour average).

Although the guidelines for PM₁₀ have been set at 50 µg m^-3 (24-hour average) and 20 µg m^-3 (annual average), PM₁₀ is considered a no threshold contaminant. This means there is no known safe level below which effects will not occur. Thus even at the guideline concentrations, health impacts can occur with exposure to PM₁₀. Concentrations of PM₁₀ measured at Hamilton, Tokoroa, Te Kuiti and Taupo are therefore likely to result in health impacts on residents of these towns.

The types of health impacts associated with exposure to PM₁₀ range from minor nose and throat irritations to more severe effects such as hospital admissions and premature mortality. The elderly and people with pre-existing conditions are more susceptible to health impacts associated with exposure to PM₁₀.

An evaluation of management options to reduce PM₁₀ concentrations has been carried out for Hamilton, Tokoroa, Te Kuiti and Taupo. This indicates a range of measures for achieving reductions in each location and an indication of the impact on PM₁₀ concentrations relative to the NES for PM₁₀. This report evaluates some of the health benefits of these management options in each location.

Table i outlines estimates of mortality likely to occur as a consequence of exposure to PM₁₀. Results indicate that although Tokoroa experiences the worst air quality in the Region, the most effective method for reducing the mortality impacts of PM₁₀ in the Region would be to implement measures to reduce PM₁₀ concentrations in Hamilton.

Health Impacts of PM10 Pollution in Hamilton, Tokoroa, Te Kuiti and Taupo: An Assessment of the Health Benefits of Management Options to Reduce PM10 [PDF, 159 KB]