Air quality & odour

Most air quality objections to a development are about construction dust, not operational emissions, and most are avoidable at the method statement stage. We write dust assessments to the IAQM guidance and we write the mitigation as something a site manager can actually do — a wheel wash location, a haul route, a trigger for damping down — rather than a page of principles nobody reads at 7am.

For operational assessments we model with ADMS or AERMOD depending on the terrain and the receptor pattern, verified against local monitoring where a suitable station exists and against our own diffusion tube survey where it does not. Verification is where these assessments are usually weak: an unverified model in a street canyon can be out by a factor of two, and a determination made on it is a determination waiting to be judicially reviewed.

Odour is a different problem because it is a perception problem with a numerical proxy. We use the FIDOL factors and dispersion modelling to a C98, 1-hour benchmark, and we tell clients the uncomfortable truth: a scheme can comply with the benchmark and still generate complaints, and the complaints are what the planning authority will act on.