• Air quality
• Drinking water quality

Air quality

Relevance

Good air quality is an important component in maintaining our quality of life, the appeal of New Zealand as a tourist destination, and the health of our people, plants and animals. PM₁₀ is the primary contaminant of concern in New Zealand and it is known to adversely affect the health of many people. Health effects associated with this contaminant include increased premature mortality, the aggravation of existing respiratory and cardiovascular diseases, hospital admissions and emergency department visits, school absences, lost work days and restricted activity days.

Current level and trends

Figure EN1.1 shows the average annual PM₁₀ levels in the air at selected monitoring sites in the five major cities. At the Christchurch site, average annual PM₁₀ levels were above the ambient guideline for all years between 1995 and 2005. The Auckland site exceeded the guideline in 2004 but has otherwise been below the guideline. The Wellington site exceeded the guideline in 2003, but has been below the threshold for the last two years. Air quality at the Dunedin site remained below the guideline until reaching the threshold level in 2004 and exceeding it in 2005. Recorded PM₁₀ levels at the Hamilton site have been consistently below the New Zealand annual guideline. Due to equipment breakdown, there was insufficient data to produce an annual average for Hamilton for 2005.

Poor air quality in New Zealand is typically associated with urban areas and is a product of vehicle emissions (Auckland) and domestic home heating (nationally). Industrial and agricultural emissions are lesser sources of PM₁₀, as are dust pollens and sea spray, which are natural sources of small particles. The annual data presented here should not be confused with daily average PM₁₀ concentrations. In September 2005, new air quality standards were introduced based on daily average PM₁₀ concentrations. Regional and unitary authorities declared 42 "airsheds" where air quality may, or is known to, exceed the standards for PM₁₀. When sufficient data is available, we will report against these standards.

Figure EN1.1 PM₁₀ concentration in selected sites, 1995–2005

Source: Ministry for the Environment, 2006, unpublished analysis
Note: Data is unavailable for: Wellington before 2000, Hamilton before 1998 and for 2005, and Dunedin and Auckland before 1997

International comparison

Ambient air quality is entirely location-specific and it is not possible to compare countries. For example, it is possible to compare annual PM₁₀ in Auckland with annual PM₁₀ in Los Angeles, but a comparison between New Zealand and the United States or other OECD countries cannot be calculated. New Zealand's urban air quality is, however, broadly comparable with or better than the air quality in a number of urban areas in OECD countries.