Hem Air Quality Index (AQI)

Loading live AQI data...

Loading historical AQI trends...

Hem, a commune in the Hauts-de-France region of northern France, sits within the Lille metropolitan area, approximately 7km southwest of Lille itself. Geographically, Hem occupies a relatively flat landscape characteristic of the North French Plain, part of the larger sedimentary basin of northern Europe. The terrain is gently undulating, with an average elevation around 25-30 meters above sea level. This low-lying position, coupled with the region’s proximity to the North Sea and the Scheldt river basin, influences local weather patterns and air circulation. Historically an agricultural area, Hem has undergone significant industrialisation, particularly linked to textile manufacturing and, more recently, logistics and warehousing due to its strategic location near major transport routes (A1 motorway). The surrounding landscape is a mosaic of farmland – primarily arable crops like wheat and barley – interspersed with smaller towns and villages. The urban-rural gradient is relatively sharp, transitioning quickly from the denser built environment of Hem and Lille to open agricultural fields. This proximity to both industrial activity and agricultural practices, combined with the flat terrain which can trap pollutants, creates specific air quality challenges. The prevailing winds, often from the southwest, can transport pollutants from larger industrial centres towards Hem, impacting local air quality.

Hem’s air quality follows a distinct seasonal pattern. Winter, from December to February, typically sees the poorest air quality. Low temperatures create temperature inversions, trapping pollutants near the ground, and increased wood burning for heating contributes to particulate matter concentrations. Calm wind conditions exacerbate this. Spring (March-May) brings gradual improvement as temperatures rise and rainfall increases, washing away some pollutants. However, agricultural activities, like fertilizer application, can introduce ammonia into the atmosphere. Summer (June-August) generally offers the cleanest air, with higher temperatures promoting dispersion and stronger winds. However, occasional heatwaves can lead to ozone formation, a secondary pollutant. Autumn (September-November) sees a deterioration in air quality as heating systems are reactivated and agricultural practices continue. Fog, common in autumn and winter, further reduces visibility and traps pollutants. Sensitive individuals – children, the elderly, and those with respiratory conditions – should limit strenuous outdoor activity during winter months and periods of fog. Monitoring pollen levels is also crucial in spring and summer. Avoiding peak traffic hours and staying informed about local air quality reports are recommended year-round.