Page 232

12.1 The Environmental Impact of Our Production–Consumption System


mainly caused by car exhaust gases, industrial activities, refineries, power stations (domestic and office consumption of gas, electricity and fossil fuels), and toxic smoke emitted by unfiltered incineration.

12.1.5 Acidification Nitric oxides (NO2, NOx) transform in the atmosphere into nitric acid (HNO3), and sulphur oxides (mainly SO2, but generally SOx) transforms into sulphuric acid (H2SO4); in contact with rain water they turn into acid and determine cumulative acidity in the soil, water and on the roofs of buildings. Other substances that cause acidification are ammoniac (NH3) and Volatile Organic Compounds (VOC). Acidification curbs the re-growth of trees in urban zones, but also in forests, it determines a corrosion of monuments and buildings, contaminates ground water (loss of aquatic flora) and can cause sanitary risks (respiratory problems). Plants, especially trees, that grow in sandy areas are affected by this phenomenon even more, because some toxic substances will enter into the solution, when a certain acidic level is reached. Acidification causes are traceable back to some agricultural activities (ammoniac emitted by livestock manure), exhaust gases emitted by cars (SO2, NOx, VOC), to activities of industries, refineries, power stations (SO2, NOx, VOC), and indirectly to domestic and office consumption of gas, electricity and fossil fuels, to domestic heating systems (NOx and VOC), and to using cleaning products that contain ammonia (NH3) and solvent-based paint (VOC). The Helsinki Protocol sanctioned a reduction of SOx emissions to 30% compared with 1980. So far the results have been good, meaning that almost all member countries have kept to their restraint objectives, mainly thanks to the gradual lowering of sulphur content in fuel and substitution of several oil derivates. Greater problems occur with the NOx emissions. The objectives of the Sofia protocol – stabilising emission levels at the rate of 1987 – have not been reached. Here, needed more incisive interventions are needed in power industry processes and structures, and in different ways of transportation. Street traffic alone is responsible for 46.7% of total NOx emissions.

12.1.6 Eutrophication Phosphates (PO4, salts of phosphoric acid), nitrates (NO3, salts of nitric acid), nitric oxides (NOx), ammoniac (NH3), nitrogen oxide (N2O), and gaseous nitrogen (N2) can cause a hyper-fertilisation, which is an accumulation of nutrients in soil and water. More susceptible for these processes are lakes and artificial water basins, where the relative speed of water exchange is considerably low and facilitates the accumulation of eutrophicating substances.

Design for Environmental Sustainability  

Download: versi pdf [] versi zip [