Air quality

NIWA's Air Quality group conduct research to understand urban air and atmospheric pollution.

We undertake a variety of projects including research, contract atmospheric monitoring, and consultancy and technology transfer. With core funding from the Ministry of Business, Innovation and Employment (formerly the Ministry of Science and Innovation) for 'Sustainable Air Quality Management' our research focusses on pollutant emissions, dispersion processes and integrated management strategies.

We are experienced in consulting projects that bring cutting edge solutions to client's problems. As part of NIWA we have access to a wide range of capability, equipment, computational resources and software development skills. For the customer we provide the whole package from inception to monitoring, data collection, analysis and interpretation, model predictions and advice.

Our team's skills include:

  • instrumentation
  • data processing
  • analysis and interpretation
  • atmospheric and meteorological processes
  • dispersion modelling
  • exposure and health effects.

Instrumentation

Instrumentation includes developing new methods for measuring and assessing atmospheric pollution, processes and effects. A Scanning Mobility Particle Sizer (SMPS) has recently been introduced to our research. Novel deployment of instruments is our speciality, custom intakes for difficult locations and use of balloon or kite-based tethersondes for measurements at different heights in the troposphere. We use telemetry software on networks of instruments, which simultaneously log up to 60 variables at 1Hz resolution.

NIWA operates two mobile air quality monitoring trailers containing equipment capable of measuring a range of key air contaminants and meteorological parameters to enable quick and easy investigations of local air quality issues across New Zealand.

Read more about mobile air quality monitoring trailers

ISO 9001

We have ISO 9001 accreditation for our air quality compliance and meteorological monitoring activities.

Modelling capabilities

Our modelling capabilities involve developing new models as well as applying and extending existing ones. We are currently exploring the possibilities of combining the UK Met office's global scale Unified Model (UM) with urban scale models to examine long range transport of pollutants.

Technology transfer

Our research results are transferred into practical applications for stakeholders. We have recently developed a model estimating background concentrations of nitrogen dioxide (NO2) for the New Zealand Transport Agency. Mobile platforms are deployed, to help understand spatial variation and whether fixed point measurement sites are a good representation of dispersed pollution.

Specific techniques and instrumentation include:

Aerosols

  • Size distributions 10nm to 30µm (approx. 90 channels). 
    TSI 3080L SMPS and Grimm 1.109 Aerosol spectrometer.
  • Number concentrations with various lower cut-off sizes.
    TSI 3007, 3772, 3781, Grimm 1.109.
  • Mass concentrations PM2.5 & PM10 (National Environmental Standards - NES compliant and others).
    BAM, TEOM, Minivol, Sidepak, Dust-trak.
  • Black Carbon  Magee. 
    AE21, 22 and 51.
  • Chemical composition (Ion Chromatography).

Gases

  • NES compliant methods; NOX, CO, SO2, O3, H2S.
  • Other methods; CO, CO2, NO2, (Electrochemical, NDIR & Palmes tubes).
  • Organics (e.g. NMHC , VOC, GHGs) Canister sampling + GC/MS.
    Autosamplers collecting up to 10 samples over a 24-hour period.
  • Light path methods:
    Vehicle emissions (CO, CO2, HC, NO) ESP RSD4600.
    MAX-DOAS (NO2, SO2, Br).

Meteorology

NIWA has the equipment and knowledge for installation and operation of meteorological stations in all environments. This covers all of the commonly required parameters such as wind speed and direction, temperature, humidity, radiation and rainfall and can be done at a number of mast heights.

We have two SODARs (SOund Detection And Ranging) which provide information on wind speed, direction, turbulence, thermal structure and mixing in the boundary layer. These have been used successfully up to 500m

We have a number of tethersondes, and balloons which we use to lift meteorological and air quality equipment to carry out vertical profiling in the boundary layer (up to approximately 1 km).

Modelling

CALMET, CALPUFF, Ausroads, (Ausplume) TAPM, UM

Plume dispersion and trajectory modelling is done using sophisticated modelling techniques to carry out pollution/particle dispersion studies, and forward/backward trajectory calculations.

Windflow modelling: using the CFD-like solver Gerris to model wind-flow over and around obstructions, calculate mean and standard deviation of winds over urban areas (e.g., cities) with a horizontal and vertical resolution of typically 80m and 20m respectively.

Gerris 

Contact

Guy Coulson
09 375 4503
g.coulson@niwa.co.nz

air_quality.jpg

Pollution hanging over an urban area. [NIWA]