Exposure Research

Using land-use and traffic assignment models to derive estimates of exposure to traffic emissions and ultrafine particles.

Emission-dispersion (E-D) models and land-use regression models (LUR) have widely been used for exposure assessment but suffer from numerous weaknesses including complexity and high data requirements (E-D) and limited transferability, arbitrariness and lack of process descriptions (LUR). Further, the majority of LURs describe patterns in NO2 only.

Our team is developing a semi-empirical approach which uses a land-use-driven traffic assignment model to inform a mechanistic approach to predicting spatial variation in concentrations, combining the best features of E-D and LUR approaches. Innovations include

  • Multi-pollutant approach, including ultrafine particles.
  • Very high resolution (~10 m).
  • Use of an emission model to enable future scenarios and hind-casting.
  • Direct link between vehicles and activity (trip origin/destination and purpose)
  • Direct link between alternative land-use scenarios, altered traffic patterns and resulting concentration field.
  • Elimination of arbitrary variables and formulations giving improved geographical transferability.

Exposure to traffic emissions whilst in transit.

We, and others, have conducted measurements of exposure whilst cycling, in cars, buses or trains, such studies always leave one question unanswered - How general are these results?

Our team has a long-term interest in developing observationally-based generalised models that can predict exposure whilst travelling for whole populations. Our approach is to investigate the processes by which exposure is influenced by

  • Vehicle/mode use.
  • Road and traffic characteristics (related to route chosen).
  • Other factors (road gradient, meteorology, etc.)

In line with our TOTUS framework, our aim is to link traffic, emission and exposure models in a way that they describe emissions and exposures as outcomes of the interaction between travel demand and transport infrastructure/services. The dynamic approach will allow detailed investigations of exposure gradients and the impact of interventions.

View some relevant presentations

  • Presentation at Australia & New Zealand Aerosol Seminar, July 2009
  • Presentation at International Aerosol Conference, September 2010
  • Abstract accepted for presentation at Clean Air Conference, Auckland, August 2011
  • Presentation at Centre for Sustainable Cities, Wellington, February 2011
  • Abstract submitted to European Aerosol Conference, 2011

Micro-scale, mobile and personal observations to inform community exposure assessment

Over the last four years NIWA has invested in an observational capability focussed on the use of miniaturised and location-aware instrumentation to inform exposure assessment, with particular focus on particles. This includes

  • Car-based platform for neighbourhood-scale surveys and vehicle "chase" experiments.
  • High-resolution observations of on-road and in-car concentrations.
  • Bike-based platform for micro-scale air quality mapping and cyclist exposure studies.
  • Personal exposure packages, used for commuter exposure investigations.
  • Particles, Activity and Context Monitoring Autonomous Node (PACMAN) - for use in indoor microenvironments.

View a presentation

  • Presentation at NIWA, Auckland, 2010

Ultrafine Particles from Traffic Emissions and Childrens' Health (UPTECH)

UPTECH is a world-leading observational study currently underway in SE Queensland. UPTECH-NZ is one of several related projects around the world which seek to investigate the same basic questions in a co-ordinated way and ensure the international validity of UPTECH's findings ...more

View a presentation

  • Presentation at Public Health Association Conference, Dunedin, 2009.