Carbon & Emissions
Air Quality Consultants
Delta-Simons was asked to undertake a Dispersion Modelling Assessment in support of a Planning Application for the installation of a 1,800kW multiple multifuel biomass boiler-system at an existing industrial facility in Cumbria.
The planning application for the Proposed Development required an Air Quality Assessment to be undertaken, as requested by the Local Authority's Environmental Health Officer (EHO), in order to assess ground level concentrations of pollutants generated by the combustion process. We aided project design by determining the appropriate height for the proposed chimney stacks.
The Site is located in a predominantly rural area and as such potential impacts on ecological designations were an important consideration. These included a Special Protection Area (SPA), and several Special Areas of Conservation (SAC).
Scope of Works
The scope of assessment was determined through review of local and national policy and guidance; baseline data from various sources; details of the proposed plant; and identification of nearby existing receptors and their sensitivities.
Full dispersion modelling was undertaken using one of a number of specialist Air Quality software packages with which we are experienced. A complex model was developed to incorporate local conditions, including meteorological data and buildings, thereby appropriately representing the Site and its surrounds.
Annual mean concentrations of nitrogen dioxide (NO2) were predicted at existing human receptor locations for scenarios 'without' and 'with' the Proposed Development and compared with the relevant air quality objectives (AQOs) and significance criteria provided by the Institute of Air Quality Management (IAQM) and Environmental Protection UK (EPUK). For ecological receptors, oxides of nitrogen (NOx) were considered along with nitrogen and acid gas deposition rates, with impacts compared to criteria derived from Environment Agency guidance.
Outcome / Client Benefits
The results of the dispersion modelling assessment demonstrated that the predicted effects would be not significant at any sensitive human receptor locations and that there were was no risk of exceedances of the relevant air quality objectives as a result of the operation of the Proposed Development. The assessment also showed that NOx levels, nitrogen and acid gas deposition rates would not be significantly affected at any designated ecological sites as a result of emissions from the biomass boilers at the designed stack height.
The Proposed Development was shown to comply with the relevant regulations, and it was demonstrated that there were no air quality constraints that would restrict permitting consent. Furthermore, the assessment of stack heights enabled us to demonstrate the most commercially acceptable design.