Air Domain Report - On-road transport emissions by pollutant 2001-2012

Ministry for the Environment


Source: National Institute of Water and Atmospheric Research

From 2014 Air domain report for the Ministry for the Environment by Statistics New Zealand

Indicator: Emissions of key pollutants from on-road vehicles

Related topic: Transport emissions (pressure)

Indicator definition: Estimated tonnes of emissions from on-road vehicles for these pollutants: carbon monoxide, volatile organic compounds, nitrogen oxides, PM10, and PM2.5.

Background: Emissions from transport sources include nitrogen oxides, carbon monoxide, sulphur dioxide, particulate matter, volatile organic compounds, and other pollutants. The health effects caused by exposure to these pollutants are related to increased lung and heart disease incidents.

Presentation of indicator components: Estimated total emissions (tail pipe and brake and tyre wear, in kilotonnes) from on-road vehicles for these pollutants:
carbon monoxide
volatile organic compounds
nitrogen oxides

Methodology: This indicator uses a model developed for the New Zealand Transport Agency and Auckland Council to estimate emissions from New Zealand’s vehicle fleet over time. The model considers the types of vehicles on the road, their fuel efficiency, and the distances and speed they travel. See NIWA’s Indicators for Environmental Domain Reporting report for more information. Information on accessing the model is available from the New Zealand Transport Agency website.

Data coverage: National (2001–12)

Data source: Ministry of Transport data series used, available from the Ministry of Transport website:
fleet composition (TV034)
vehicle speed (SS008)
congestion (NR002)
vehicle fleet statistics (TV001).
See NIWA’s Indicators for Environmental Domain Reporting report for more information.

Limitations to data and analysis: The model is based on internationally recommended approaches, uses internationally recognised emission factors, and is validated with road testing results. However, limited validation of the model outputs for heavy diesel vehicles exist. See section 2.6 of the following report for further information. See NIWA’s Indicators for Environmental Domain Reporting report for more information.

Modelling assumptions and parameters are reviewed periodically to ensure the model best reflects the emissions from on-road transport at a given point in time. Any changes to the model are peer-reviewed internationally.

The modelling assumes that the vehicle fleet composition is the same throughout New Zealand as the regional information is of variable quality.

Estimated pollutant emissions do not always equal the measured concentrations. Other factors also contribute to concentrations, such as weather conditions.

Additional information to understand the link between the topic and the indicator: Only national on-road transport is included. Off-road transport, including sea, air, and rail transport, is excluded.

Changes to time series: None


Detailed definitions can be found here:

Data provided by

Ministry for the Environment

Dataset name

Environmental Reporting: Air Domain Report 2014


How to find the data

At URL provided, download 'Excel files'

Import & extraction details

File as imported: Environmental Reporting: Air Domain Report 2014

From the dataset Environmental Reporting: Air Domain Report 2014, this data was extracted:

  • Sheet: Table 15
  • Range: C11:G22
  • Provided: 60 data points

Dataset originally released on:

May 16, 2014

Purpose of collection

The Ministry for the Environment and Statistics New Zealand commissioned NIWA to produce a report that provides information for New Zealand’s Environmental Reporting Series: 2014 Air domain report. This report provides the methodology and results for the national air domain indicators – on-road vehicle emissions, annual average PM10, and health impacts due to exposure to PM10. It also includes information on natural sources of pollutants, and the influence of meteorological conditions on air quality.