Report: TR04/30

Author: Emily Wilton (Environet Ltd.)

Abstract

Air quality monitoring in Taupo from 2001 to 2003 has shown concentrations of PM10 in excess of the Ministry for the Environment’s ambient air quality guideline and National Environmental Standard (NES) of 50 µgm-3 (24-hour average). Based on 2003 data, the guideline may have been exceeded on 12 days if data are extrapolated for missing values. The NES allows only one exceedence per annum of 50 µg m-3 (24-hour average).

Sources of PM10 and other contaminants in Taupo had previously been evaluated for the year 2000 using the emission inventory methodology. This involved a domestic home heating survey and an evaluation of motor vehicle emissions based on a road network model for Taupo. The industrial component relied on a 1997 industrial emissions assessment for the Waikato region (Noonan, 1997).

This study updates the previous inventory data and includes an assessment of the sources of industrial emissions. Contaminants included were particles (PM10 and PM2.5), carbon monoxide, nitrogen oxides, sulphur oxides, volatile organic compounds, carbon dioxide and benzene. This report primarily focuses on emissions of particles (PM10), as concentrations of PM10 in Taupo are in breach of the NES. The PM10 sources included in the inventory assessment were domestic heating, motor vehicles, industrial and commercial activities and outdoor burning.

Emissions from domestic home heating were evaluated using the results of a household survey of heating methods. Woodburners and gas were found to be the dominant home heating methods in Taupo being used in the main living area in around 47% and 37% of homes respectively. Electricity was also a common heating method with around 34% of households using that method. Many households used more than one method to heat the main living area of their home.

The main source of PM10 and PM2.5 emissions in Taupo was domestic home heating, which accounted for around 88% and 90% of total emissions respectively. For PM10, the remaining 12% was distributed between motor vehicles (9%), outdoor burning (3%) and industrial emissions (<1%). Motor vehicles also accounted for about half of the CO and CO2 and 90% of the NOx emissions.

Taupo Emission Inventory 2004 [PDF, 1.3 MB]