Figure 4.2: Examples of applying appropriate levels of assessment

Text description of figure

This figure relates the level of assessment required to the scale and complexity of the proposal as defined by the following key factors:

• Scale of development
• Pollution prevention measures
• Complaints and compliance
• Key pollutants released
• Airshed designation
• Existing air quality
• Physical geography
• Land use

A Tier 1 assessment requires only a simple notification of the key features of the proposal. An example of this for the above key factors would be a small scale plant (e.g. workshop paint spray booth) with simple pollution prevention measures (e.g. VOCs abated), no previous complaints, minimal VOC emissions in an area that is not gazetted as an airshed with good existing air quality, no complex geography on land that is zoned commercial.

A Tier 2 assessment requires largely qualitative assessment with screening-level modelling only. An example of this for the above key factors would be a medium scal plant (e.g. 5-10 MW gas fired boiler) with moderate pollution control (e.g. low NOx burners), minor historical dust complaints from former industry, moderate NOx and CO emissions, in a gazetted airshed which has, however, good air quality (for NO2 and CO) on land zoned industrial set in simple terrain (e.g. inland site with gently undulating topography).

A Tier 3 assessment requires a largely quantitative assessment with increased complexity in modelling and reliance on site-specific data. An example of this for the above key factors would be a large scale plant (e.g. > 20 MW boiler) with no emissions control (e.g. high sulphur fuel with no SO₂ abatement), residents sensitised to odour, noise and dust, significant emissions of SO₂, NOx, PM₁₀, dust and odours in a gazetted airshed with constrained air quality (e.g. some NES breaches) on a site bordering residential and tourist areas that is coastal with complex topography.