A square designed to welcome — powered by something that didn't
Grantham Market Place sits at the centre of the town's civic life — a pedestrianised square that planners explicitly shaped to be a welcoming and flexible public space. On paper, and on ordinary days, it largely delivers on that. On market days, however, the square ran on diesel generators: engines idling at close quarters, filling a confined outdoor space with low-frequency noise and exhaust at pedestrian height.
The market was open to everyone in any formal sense. Nobody was turned away at the edge of Market Place. But openness in the legal sense and genuine usability are not the same thing, and the gap between them is what this piece is about.
Who found the generator-powered market genuinely difficult to use — and why? The answer turns on two sensory channels that diesel engines affect most acutely, and on a population for whom those channels are already working harder than average.
What a generator does to a public square
Two mechanisms are at work, and they operate independently of each other.
The first is acoustic. A stationary diesel generator produces not a burst of sound but a continuous baseline — low-frequency noise that persists throughout its running hours. Electrical generators are a recognised outdoor noise source category, alongside traffic and construction equipment. In a pedestrianised square, where surrounding buildings reflect sound rather than disperse it, that baseline raises the ambient sound floor across the whole space. The practical consequence for anyone standing at a market stall is that normal speech becomes harder to follow, and compensating means raising your voice toward shouting level. The noise does not have to be dramatic to have this effect — persistence and frequency range do the work. No decibel measurements for Grantham Market's generators are available in the published sources, so this is a qualitative account of a well-documented mechanism.
The second mechanism is olfactory and respiratory. A stationary generator, unlike a vehicle in motion, has no forward movement to disperse its exhaust. It sits in one position and expels fumes at the height where people are standing and breathing. The emissions profile of a stationary diesel engine differs from road traffic precisely because of this: particulates and gases settle in the immediate area rather than trailing away along a route. In a confined square during market hours, that exhaust concentrates at breathing height throughout the space.
The two channels are independent. Someone may find the noise tolerable but the fumes distressing, or the reverse — the environment does not need to be overwhelming on every front simultaneously to exclude.
Who those conditions were hardest on
Sensory processing disorder disrupts precisely the two modalities that a running generator targets. People with SPD may find auditory stimuli — including persistent low-frequency noise — difficult to filter, and olfactory stimuli similarly hard to modulate. Both channels activate simultaneously in a generator-powered square, without either being avoidable for someone moving between market stalls.
The condition does not sit in isolation. SPD co-occurs with autism spectrum disorder, ADHD, Tourette's syndrome, and dyspraxia, which means the affected population is considerably wider than any single diagnosis implies. Autism itself lists sensory processing differences as a core diagnostic feature — not a secondary or occasional trait, but part of what the condition is. Taken together, conditions that involve heightened sensory sensitivity account for a meaningful cross-section of any town's population of children and adults.
Duration compounds the picture. Research into sensory processing sensitivity identifies a key neurological characteristic: in people whose central nervous system does not readily habituate to incoming stimuli, environmental exposure accumulates rather than levels off. A 40-minute market visit — pausing at stalls, making decisions, carrying out a transaction — is physiologically unlike a brief pass-through. The noise floor does not recede into the background; the fumes do not become less present. Assessments of impact that focus on peak intensity rather than sustained exposure miss this entirely, and it is planners and designers who most commonly reason in terms of peak conditions rather than cumulative ones.
For people with asthma, COPD, or chemical sensitivities, the barrier is more direct: diesel exhaust concentrated at pedestrian height in a confined square is a physiological deterrent, not a minor inconvenience.
The planning paradox built into Market Place
The paradox follows directly from that redesign intent. Generator dependency was never a deliberate design feature — it was a practical default. Mains power was unavailable at Market Place, so traders used what was portable. Nobody decided the square should be exclusionary for people with sensory sensitivities or respiratory conditions. It became so anyway.
The structural tension is this: the more someone needed a calm, predictable, accessible public space, the less able they were to use this one during market hours. The very population that good public-space design is most supposed to serve — people whose tolerance for persistent noise and concentrated fumes is lower than the assumed average — encountered the highest barrier to entry. The accessibility gap was greatest precisely where the inclusion intent was strongest.
This is a pattern that extends beyond Grantham. Public realm investment tends to concentrate on visible elements: paving, furniture, lighting, layout. Utility infrastructure — what actually powers a space — is treated as a technical procurement decision, rarely as an accessibility one. But that invisible layer of provision can determine, in practice, who a space is for. The Grantham case is a clear instance of a common mechanism: a human-centred design goal undermined not by hostile intent but by an unexamined background assumption about what the default infrastructure was allowed to be.
What the £275,000 mains upgrade removed
Removing that barrier had a specific price tag and a specific engineering solution. Of the £880,000 reallocated from the Future High Streets Fund, £275,000 was spent on permanent power infrastructure designed in partnership with National Grid — eight cabinets in total, four across Market Place and four in Westgate. Each cabinet supplies both three-phase and single-phase electricity, meaning market traders and event organisers can connect directly to the grid without auxiliary power equipment on site.
The practical consequence is the removal of the generator as a presence in the square. No diesel units running through a market day means the continuous low-frequency noise floor is gone, and diesel exhaust is no longer being expelled at pedestrian height across a confined public space. The MSK Knowledge Base's Grantham Human Factor research describes this outcome precisely: the installation 'fundamentally alters the acoustic and olfactory landscape' of the market.
The stalls remain. The traders remain. The square is the same square. What changes is the sensory environment those things sit inside — and, by extension, who can comfortably occupy it. This is the nature of the upgrade: not a visible transformation of the built form, but a change to the invisible layer of provision that was, in practice, setting the terms of access.
Who can now actually use the market
For people with auditory sensory sensitivities or respiratory conditions, the practical change is clear. The low-frequency noise floor that persisted through a market visit — forcing every conversation to a shout, keeping sensory systems at higher alert — is gone. So is the diesel exhaust at pedestrian height across a confined public square. Neither was ever recorded as a design choice; both are now removed.
Whether that translates into more people from those groups attending is not yet measured. No footfall data has been collected against the upgrade, and no one from Grantham with these conditions has spoken on record about what market days were like before, or what they are like now. That is an honest gap, not a reason to doubt the mechanism.
What is clear is narrower and more concrete: a decision about power supply — logged as a utility procurement, funded through a regeneration scheme — determined who could comfortably use Market Place on a market day. For a square that has hosted Grantham's traders for generations, that is not an abstract point about infrastructure policy. It is a question about access, and it was being answered, quietly, by which kind of electricity the stalls ran on.
- [1] Noise pollution. https://en.wikipedia.org/?curid=66599 https://en.wikipedia.org/?curid=66599
- [2] Diesel exhaust. https://en.wikipedia.org/?curid=1202358 https://en.wikipedia.org/?curid=1202358
- [3] Autism. https://en.wikipedia.org/?curid=29113700 https://en.wikipedia.org/?curid=29113700