Periodically, the quantities of air pollutants discharged into air throughout the Auckland region are estimated through comprehensive emission inventories. For the 2016 emission inventory, the main source categories have been separately considered for future inclusion in a summary report.

This report updates previous inventories to estimate the quantities of various air pollutants emitted in 2016 from consented industrial point sources (predominantly chimney stacks).

Industry is commonly associated with discharges of contaminants into air. In 2006 industrial point sources contributed 15 per cent (476 tonnes) of Auckland’s total anthropogenic fine particulate emissions.

This update demonstrates that closures and upgrades to consented industries throughout Auckland have greatly reduced these emissions. Industrial point sources are estimated to have discharged 302 tonnes of fine particulate matter less than 10μm in diameter (PM₁₀) in 2016, 34 per cent reduction in estimated industrial emissions over a decade. This reduction however did not achieve the targeted 50 per cent reduction of PM₁₀ emissions from 2006 levels, as set by the Auckland Plan (Auckland Council, 2012).

Notable industrial discharges that ceased between 2006 and 2016 include Auckland’s two thermal power stations, the Pacific Steel smelting facility, and the New Lynn brickworks. These industries collectively represented 1055 tonnes of nitrogen oxide (NO_x) emissions in 2006, a third of Auckland’s total emissions that were estimated to occur at that time.

Numerous other consented industries have implemented major air pollution controls since 2006, resulting in significant declines, particularly for PM₁₀ emissions. For example, the O-I Glass smelter in Penrose upgraded the emission control system of its glass furnaces in 2012 to reduce PM₁₀ emissions from an estimated 40 tonnes in 2006 to four tonnes in 2016.

Compared to other international cities, there are few significant heavy industrial activities in the Auckland urban area. Reticulated natural gas is the dominant method of generating heat and energy for Auckland’s industries. The only industrial site that consumes significant quantities of coal is NZ Steel at Glenbrook, near to the southern boundary of the Auckland region, approximately 40km to the south of the Auckland CBD. NZ Steel is the largest industrial emitter of all common air pollutants in the Auckland region, with its emissions of fine particulates estimated to account for 80 per cent of all point source mass emissions from Auckland’s consented industrial sites. Within the Auckland urban boundary, industry is estimated to have emitted 47.6 tonnes of PM₁₀ and 775 tonnes of NO_x in 2016.

Auckland Council technical report TR2018/019