Restaurant Odour Assessment for a London Borough Application

The Project

Our client, a national casual-dining chain, was preparing a planning application to convert a Use Class E retail unit into a restaurant in an inner-London borough. The proposal involved a typical mid-market kitchen specification with grilling, frying and pan-cooking — activities recognised in the EMAQ+ guidance as moderate to high odour-generating processes.

The site sat within a mixed-use, predominantly residential street. Adjacent first-floor flats were located directly above the unit, and a children's nursery lay within 30m of the proposed extract location. With receptors that close, odour was always going to be the determining environmental issue for the application.

The Challenge

The borough had refused two similar applications in the previous 18 months on odour grounds, and Environmental Health had a known position that low-level discharge in this kind of context was unlikely to be acceptable. The client's planning consultant brought us in early but the timeline was already tight: an 8-week determination period was running, and the architect's drawings showed the extract terminating at low level, just 1.5m above the flat-roof structure — well below the height of nearby residential windows.

A first-pass screening using the EMAQ+ methodology indicated that, without changes, the predicted odour effect at the closest receptors would be high. That was unlikely to be defensible at planning, and a refusal would have set the brand's roll-out programme back by months.

Our Approach

We carried out a full odour impact assessment to the EMAQ+ (2018) methodology, classifying the cooking processes, characterising the receptor sensitivity and quantifying the required level of odour control. The output was a clear specification: a 3-stage filtration train comprising grease filtration at the canopy, activated carbon for VOC and odour adsorption, and UV-C ozone treatment for residual organic compounds. Filtration alone was not enough — discharge dispersion was equally critical.

We specified the discharge characteristics needed to achieve acceptable dispersion: a vertical, uncapped stack terminating at +1m above the highest adjacent ridgeline, with an exit velocity of 8 m/s to ensure the plume cleared the building wake zone. We then sat down with the architect and worked through the building's stair core to identify a viable route for the duct, threading it up through a redundant service riser to a roof-level termination.

Throughout the assessment we maintained a dialogue with the borough's Environmental Health team, sharing the proposed specification at draft stage and confirming that the approach addressed the concerns that had triggered previous refusals. This pre-engagement is, in our experience, almost always worth the effort — an officer who has seen the design before formal validation is much less likely to escalate concerns at the consultation stage.

The final assessment report set out the kitchen process, the EMAQ+ classification, the predicted unmitigated effect, the specified mitigation, and the residual effect with mitigation in place. The conclusion was that, with the specified extract system, the residual odour effect would be negligible at all sensitive receptors.

The Outcome

The application was determined under delegated authority within the 8-week target. Environmental Health raised no objection, and the planning conditions attached to the consent were limited to standard odour management plan and post-completion verification requirements — both of which are routine to discharge. The tenant fit-out proceeded on programme and the unit opened to the public on its planned launch date.