Lewes Air Quality Index (AQI)

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Lewes, nestled in the county of East Sussex, England, occupies a unique geographical position within the South Downs National Park. Situated at coordinates 50.8747, 0.0117, the town is built in a valley where the River Ouse, River Cuckmere and River Brent converge. This valley location, while picturesque, creates a natural funnel for air, potentially trapping pollutants during calm weather conditions. The surrounding landscape is dominated by the chalk hills of the South Downs, rising sharply to the north and providing a degree of shelter, but also limiting air dispersion. Lewes’s elevation varies considerably within the town itself, contributing to localised variations in air flow. Historically, Lewes was a key port, and while commercial shipping has declined, road traffic now represents a significant source of emissions. The urban-rural gradient is relatively sharp; immediately surrounding the town are agricultural lands, primarily pasture, with more intensive farming further afield. There’s no heavy industrial belt directly adjacent to Lewes, but the A27 trunk road, a major transport artery, runs nearby, impacting local air quality. The proximity to the English Channel introduces maritime influences, including sea breezes that can help to disperse pollutants, but also potentially bring in pollutants from the continent. The town’s compact form and historic street layout can also contribute to localised air stagnation.

Lewes experiences a temperate maritime climate, and its air quality follows a distinct seasonal pattern. Winter, from November to February, often sees poorer air quality due to increased use of solid fuel heating, combined with temperature inversions – particularly in the valley – trapping pollutants near ground level. Calm, cold conditions exacerbate this, with wood smoke becoming a dominant concern. Spring (March-May) generally brings improvement as temperatures rise and heating demand decreases, aided by more frequent westerly winds. However, agricultural activities, such as fertiliser application, can contribute to ammonia levels. Summer (June-August) typically offers the best air quality, with prevailing southwesterly breezes dispersing pollutants effectively. However, occasional heatwaves can lead to increased ozone formation. Autumn (September-October) sees a return to poorer conditions as heating use increases again, and damp, still weather becomes more common. Fog, a frequent occurrence in the valley during autumn and winter, can trap pollutants and reduce visibility. Sensitive individuals – those with respiratory conditions, the elderly, and young children – should be particularly cautious during winter and autumn months, limiting strenuous outdoor activity on high pollution days. Monitoring local forecasts and avoiding peak traffic times are advisable throughout the year.