Liedekerke, nestled in the heart of Flemish Brabant, Belgium, occupies a gently undulating landscape characteristic of the Pajottenland region. Situated at coordinates 50.8667, 4.0833, the terrain is primarily composed of loamy soils, historically dedicated to agriculture, particularly barley and hops cultivation. The city’s elevation is relatively low, averaging around 20-30 meters above sea level, contributing to limited natural air dispersion. Liedekerke benefits from proximity to several smaller waterways, tributaries of the Dender river, which, while aesthetically pleasing, can contribute to localised humidity and potential for temperature inversions. The urban-rural gradient is quite sharp; Liedekerke transitions rapidly into expansive agricultural fields to the north and east, and smaller, dispersed settlements to the south and west. While not directly within a major industrial belt, its location within the broader Brussels-Antwerp-Ghent ‘diamond’ means it experiences some influence from regional industrial emissions transported by prevailing westerly winds. The surrounding agricultural practices, including fertilizer use, contribute to ammonia emissions, impacting local air quality. The density of livestock farming in the Pajottenland also plays a role. The city’s compact urban form, typical of many Flemish towns, can trap pollutants during calm weather conditions.

Liedekerke’s air quality follows a distinct seasonal pattern. Winter, from November to February, often sees poorer air quality due to increased residential heating with wood and fossil fuels, coupled with frequent temperature inversions trapping pollutants near the ground. Calm, damp conditions exacerbate this, particularly during prolonged periods of fog. Spring (March-May) brings a gradual improvement as temperatures rise and heating demand decreases, though agricultural activities like fertilizer spreading can temporarily elevate ammonia levels. Summer (June-August) generally offers the cleanest air, aided by prevailing winds and higher temperatures promoting dispersion. However, heatwaves can trigger photochemical smog formation, increasing ozone concentrations. Autumn (September-October) presents a transitional period. The return to heating, combined with agricultural harvesting and the onset of damp, still conditions, can lead to a decline in air quality. Sensitive individuals – children, the elderly, and those with respiratory conditions – should be particularly cautious during winter and autumn months. Avoiding strenuous outdoor activity on still, cold days and monitoring local conditions is advisable. Periods of strong westerly winds in summer are generally favourable for outdoor pursuits.