Environment and Health- Impact of Air and Water Pollution
Environment includes a host of factors of which air and water are the two major components. Air pollution is caused by both natural and man-made sources. Major man-made sources of ambient air pollution include industries, automobiles, and thermal power generation. In indoor environment, tobacco smoke and combustion of solid fuels for cooking and heating are the most significant sources of air pollution. In addition, construction material, carpeting, and home cleaning agents like insecticides can also be significant sources of chemical and biological indoor pollutants.
Air pollution has both acute and chronic effects on human health. Health effects range from minor irritation of eyes and upper respiratory system to chronic respiratory diseases (e.g. lung cancer, heart disease). The respiratory ailments attributed to air pollution have been shown to cause acute respiratory infections in children and chronic bronchitis in adults. It has also been shown to worsen the condition of people with pre-existing heart or lung disease. Among asthmatics, air pollution has been shown to aggravate the frequency and severity of attacks. Both short-term and long-term exposures have been linked to premature mortality and reduced life expectancy.
Health impact of air pollution depends on the pollutant type, its concentration in the air, length of exposure, other pollutants in the air, and the susceptibility of the individual. Different people are affected by air pollution in different ways. Poor people, undernourished people, very young and very old, and people with pre-existing respiratory diseases are more at risk. In cities, poor people tend to live and work in most heavily polluted areas. In rural areas, poor are more likely to cook with dirtier fuels. In some countries, air quality standards tend to be more lax around industrial areas in cities where many poor live. Malnutrition, inadequate access to health services, etc. aggravate the susceptibility of poor to adverse health consequences of air pollution. Air pollutants can also indirectly affect human health through acid rain. This is caused by polluted water with chemical substances evaporating to the atmosphere. This phenomenon, which is happening all over the world, is contributing to changes in the global climatic conditions. Such conditions are resulting in what has popularly come to be known as ‘global warming’ with the resultant variations causing the sea level to rise. Consequent to global initiatives in response to the health concerns of increasing air pollution, many countries have adopted tighter emission standards. This has helped in the levels of certain types of air pollutants to decline in many developed countries. However, even at much reduced levels, air pollution continues to threaten public health in these countries. In developing countries, on the other hand, the ambient air pollution is a major health threat particularly in urban areas. Several factors contribute to the worsening air pollution which include rapid growth in urban population, increasing industrialisation, and rising demand for energy and motor vehicles. Other factors which add to the problem include: poor environmental regulation, less efficient production technologies, congested roads, and age and poor maintenance of vehicles.
The problem of air pollution in the rural areas of developing countries relates to indoor exposures due to the use of unprocessed solid fuels (biomass and coal) for cooking. These fuels are typically burned indoors in simple household cooking stoves, such as a pit, three pieces of brick, or a U-shaped construction made from mud. The fuels are thus burnt inefficiently with the resulting pollutants not vented out properly. High volumes of a number of health-damaging airborne pollutants are generated indoors, resulting in high exposures, especially to women who do the cooking and young children who stay indoors with their mothers. The individual peak and mean exposures experienced in such settings are often much greater than the safe levels recommended by international bodies (like the World Health Organisation: WHO). According to the 2002 World Health Report, indoor air pollution from combustion of solid fuels for cooking and heating is one of the eight most important risk factors in global burden of disease. In poor developing countries, indoor smoke from solid fuels ranks fourth (behind only under-nutrition, unsafe sex, and unsafe water/sanitation/hygiene) accounting for an estimated 3.7 per cent of the disease burden. Urban air pollution additionally accounts for 1.4 per cent of premature deaths and 0.8 per cent of the global disease burden. The estimates are based only on the impact of air pollution on mortality. They do not account for morbidity impact or specific disease centred health outcomes which are also associated with indoor smoke.