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Odour pollution: More than just a nuisance
Residents of Westbury, a quiet market town in England, have long endured an overpowering stench from a nearby waste treatment facility. For Elaine Corner, a retired teacher, the smell is so unbearable that it disrupts daily life, forcing her to keep windows shut and avoid outdoor activities. "It feels like walking behind an open bin lorry," she says. "You can't use your garden or go for a walk without feeling sick."
The science behind smell and health
Research reveals that unpleasant odours do more than cause discomfort-they can trigger physical and mental health issues. Studies link urban malodours to headaches, nausea, breathing difficulties, and sleep disturbances. Johan Lundström, a smell scientist at Sweden's Karolinska Institute, explains that the olfactory system acts as an early-warning mechanism, processing threats within 300 milliseconds of inhalation. "Smell primarily functions to warn us about danger," he says.
This defensive response can heighten sensitivity to odours. Lundström's research shows that pairing a smell with an electric shock makes people detect it at much lower concentrations, a survival trait that persists even with faint scents. For example, hydrogen sulfide-a gas produced in sewage treatment-can be detected at just 0.5 parts per billion, signaling potential toxicity.
Mental and physical toll
While pleasant scents, like forest air, can boost mental health, bad odours have the opposite effect. A 2021 review found biological links between foul smells and symptoms like vomiting, likely due to the vagus nerve's role in connecting the brain and gut. However, scientists stress that more research is needed to fully understand these physiological impacts.
Pamela Dalton, a cognitive psychologist at the Monell Chemical Senses Center in Philadelphia, notes that health effects depend on individual perception. "The more anxious you are about an odour, the greater its impact," she says. Persistent smells can lead to "maladaptive actions," such as avoiding outdoor exercise or social gatherings, further harming well-being.
Unequal exposure and regulatory gaps
Odour pollution is often hyperlocal, affecting some neighbourhoods while sparing others. Amanda Giang, an environmental policy researcher at the University of British Columbia, found that residents in Vancouver's affected areas may not even realize their neighbours endure foul smells. Disadvantaged communities bear the brunt of this burden, with studies showing low-income households are more likely to live near landfills or industrial sites.
Regulatory efforts are uneven. Chile recently introduced rules for fish feed plants, while Lithuania tightened limits on industrial odours in residential areas. In Westbury, Hills Waste Solutions, the facility operator, says it is collaborating with the Environment Agency to address complaints.
The silver lining: A functioning sense of smell
A keen sense of smell is tied to better health. Research shows people with strong olfactory abilities enjoy food and intimacy more, while those with anosmia (smell blindness) often struggle with appetite and diet quality. Lundström notes, "If you lose your sense of smell, your appetite can disappear."
Worse, a 2018 study linked poor smell to a 46% higher risk of death within a decade among older adults, possibly due to links with cardiovascular and neurodegenerative diseases. Dalton, who has studied odours for decades, quips, "I don't mind bad smells-they mean my nose is working!" For Corner and others like her, though, relief remains elusive.
