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Industry and air quality

Air
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Industrial sites can produce a variety of air contaminants, depending on the type of industry and its processes.

Industrial air discharges in the Waikato region

Most industrial air emissions are released by a relatively small percentage of industrial sites. For example, a survey found that over 80 per cent of all the industrial air emissions are generated by only nine per cent of industrial sites.

Many of these large emission sources are near Tokoroa and Huntly, such as pulp and paper manufacturers and thermal power plants.

However, based on air emission inventory assessments, the overall contribution of industry emissions to total urban airshed emissions is typically small. The industrial contribution to contaminant concentrations in urban airsheds is likely to be even less because industrial discharges are typically via high stacks that promote more effective dispersion of contaminants.

Local landscapes and weather conditions will also influence the effect of these sources on air quality. 

Industrial air contaminants

Industrial sites can produce a variety of air contaminants, depending on the type of industry and its processes. Industrial emissions include particulates (very small particles - called PM10), combustion gases, volatile organic compounds (VOCs), and odours.

An assessment of emissions from 107 industrial sites showed that:

  • Quarrying and mining produce most fine particles (PM10) - in the form of fine dust.
  • Most carbon monoxide (CO) from industry is produced when fossil fuels are burnt to generate heat.
  • Most nitrogen oxides (NOx)are produced by thermal power stations.
  • Emission of sulphur oxides (SOx) by industry comes from the burning of high sulphur coal.
  • Most volatile organic compounds (VOCs) are released by the timber and paper processing industry.
  • Most carbon dioxide (CO2)comes from a few large industry types - power generation, timber and paper processing.

Emissions of different industry types

The table below shows the percentage of six key contaminants produced by industry types.

Estimated percentage emission of contaminants by major industry type
Industry type PM10 CO NOx SOx VOC CO2
Chemical manufacturing 6.8 16.7 3.6 2.3 0.4 3.4
Food processing 12.8 17.0 13.3 42.5 0.1 12.6
Quarrying and mining 48.5 0.6 0.2 0.1 1.7 0.1
Power generation 0.5 21.3 73.7 0.1 32.4 55.0
Timber and paper processing 21.3 39.9 5.7 16.0 65.3 23.8
Other 10.1 4.5 3.5 39.0 0.1 5.1

What Waikato Regional Council does to manage industry emissions

Waikato Regional Council's air quality monitoring programme monitors the levels of air contaminants at sites around the region. 

We have policies and regulations for air discharges. These are set in the Regional Policy Statement and the Waikato Regional Plan.  Our rules require resource consents for activities that might release a significant amount of contaminants into the air. Resource consents set conditions on discharges to air that prevent or limit unwanted effects on air quality so that:

  • adverse effects on human health are avoided
  • there are no objectionable effects as a result of odour
  • there are no objectionable effects as a result of particulate matter
  • significant adverse effects on visibility are avoided or remedied
  • air quality doesn't damage buildings or other structures.

We also support industry-based guidelines and codes of practice that help reduce air pollution.