TRAFFIC UPDATES: Roads across the north island have been impacted by recent weather events. We’ll provide updates on our Journey Planner website as information becomes available. View our traffic map for road closures and delays(external link)

SCAM ALERTS: Report a phishing scam or learn about the latest phishing emails

CONTACT CENTRE WAIT TIMES: Our Contact Centre is currently experiencing significant wait times. View frequently asked questions

ONLINE TRANSACTIONS: We are experiencing issues with credit and debit card transactions on our website. We are working with the payment provider to resolve this as soon as we can. 

CONTACT CENTRE WAIT TIMES: Our Contact Centre is currently experiencing significant wait times. View frequently asked questions

REGO AND RUC LABEL ERROR: There was a postage error with labels purchased on the 15 August 2022. Find out more

ROAD USER CHARGES (RUC) DISCOUNT: Find out more about the temporary RUC reduction scheme

ONLINE SERVICES: We are currently experiencing issues with all our online services at the moment. We are working to resolve the services as soon as possible. We apologise for any inconvenience caused.

COVID-19 SERVICES UPDATE: Information on Waka Kotahi services, extensions and more

ONLINE SERVICES: We currently have an issue with receiving some payments and are working to resolve this issue as quickly as possible. We apologise for any inconvenience.

EASTER WEEKEND – PLAN AHEAD: Heading away for the long weekend? Check our holiday journeys tool(external link)

SCAM ALERTS: Refund email and Vehicle licence (rego) renewal phishing emails

CONTACT CENTRE PHONE LINES: Our Contact Centre phone lines are currently unavailable. View frequently asked questions

Back to Resources

Research Report 516 Detailed observations and validated modelling of the impact of traffic on the air quality of roadside communities

Published: | Category: Safety, security and public health , Research programme , Research & reports | Audience: General

Detailed observations of air quality and local meteorology were conducted on either side of a stretch of the Auckland southern motorway, and in the surrounding residential neighbourhood. The data revealed emissions from motorway traffic contributed, on average, to a 10% elevation in concentrations of particulate matter at a roadside site relative to a setback site (150m away or more) and to a doubling in concentrations of nitrogen dioxide. National environmental standards for air quality were not exceeded, but international health research indicates that the spatial variation in traffic-related air pollutants observed in this study represent a risk that is not currently accounted for in risk assessments in this country.

The observational data captured was used to evaluate four different roadside air quality modelling approaches. The most commonly used model in regulatory context (Austroads) was found to be conservative, but its effectiveness could be undermined by the use of inappropriate (particularly off-site) estimates of background air quality. Less commonly used assessment methods (passive monitoring, semi-empirical and regression modelling) were shown to offer several advantages for assessment.

Keywords: air pollution, air quality, dispersion modelling, nitrogen dioxide, particulate matter, state highways

Publication details

  • Author:
  • Published: February 2013
  • Reference: 516
  • ISBN/ISSN: 978-0-478-40725-9