|Initial Environmental Assessment: Urban Development - Series no 12 (NORAD, 1996)|
|Part I: Urban development. The urban environment, projects and environmental impacts.|
|3 Possible environmental impacts|
Built-up areas both impact and are impacted by the climate conditions of the location. A climate analysis may give useful information for planning of an environmentally adapted new construction or reconstruction activity. Poor climate adaptation may cause health injuries, increased consumption of energy, damages to buildings, and higher maintenance and running costs. The climate can be utilised positively in several ways, for instance through wind or thermal air movement ventilating polluted outdoor areas, or that solar energy is utilised both inside and outside the building. A climate analysis can give knowledge on:
· wind velocity and wind
direction for the various seasons,
· type of wind - whether it is warm or cold,
· angle of sunlight in relation to latitude and local conditions of shade,
· outdoor temperature,
· amount of precipitation,
· local topography, and
· how the various factors interrelate, for instance how temperature and topography affect wind.
In the tropics physical structures in urban areas (buildings, tarmac streets etc.) will be warmed up during the day, and be subjected to relatively little cooling during the night. Cities dominated by concrete and tarmac may have temperatures that are between 5-10°C higher than the surrounding countryside. Heat waves are exacerbated and may in worst cases be fatal for elderly and sick. Consumption of energy, including transport, may also contribute to the warming up of cities. In quiet, sunny weather a canopy of hot polluted air might be created over the city.
Several methods of climate adaptation might be considered in construction projects and/or physical planning. One method is the location of buildings in the landscape and the utilisation of vegetation as windbreaks or shade. The design of the buildings and use of materials may also affect indoor consumption of energy and indoor climate (cf. 3.6 and Table 3).