lämpösaareista

A heat island, or lämpösaari in Finnish, is a metropolitan area that is significantly warmer than its surrounding rural areas. This temperature difference is usually greater at night than during the day and is most apparent when winds are weak. The phenomenon is primarily caused by human activities and the built environment.

The main contributors to the heat island effect include the replacement of natural landscapes with buildings, roads, and other impermeable surfaces. These materials, such as asphalt and concrete, absorb and retain more solar radiation than vegetation and soil. This stored heat is then released back into the atmosphere, particularly after sunset, leading to higher nighttime temperatures. Additionally, waste heat generated by human activities, such as from vehicles, air conditioning units, and industrial processes, further contributes to the elevated temperatures.

The consequences of heat islands can be significant. They can lead to increased energy consumption as demand for cooling rises. Elevated temperatures can also exacerbate air pollution problems, as heat can accelerate the formation of ground-level ozone. Furthermore, heat islands can negatively impact human health, increasing the risk of heat-related illnesses and mortality, especially for vulnerable populations. Mitigation strategies include increasing green spaces, planting trees, using reflective or permeable materials for construction, and implementing cool roof technologies.