AMBIENT AIR POLLUTION AND PREGNANCY OUTCOMES: A REVIEW OF THE LITERATURE
CHAPTER ONE
INTRODUCTION
The land can be cleaned up before we use it, and purify water before we drink it, but, except in air-conditioned rooms, we must breathe air as it comes to us. Automobiles, factories, heating furnaces, power plants, trash incinerators, each add to the problem, so control is difficult. (Microsoft Encarta 2009). Air pollution is a major environmental problem throughout the world. Most air pollution problems thus result from man’s pattern of energy use and production.
Air quality is affected by economic activities which introduce pollutants into the atmosphere that pose threats to human health and other life forms on earth. It furthermore has the potential to change the climate with unpredictable, but potentially severe consequences on a local and global scale. Because large bodies of air cannot be contained, atmospheric pollution can only be controlled at its source.At present there is no comprehensive information on air quality or on the levels of emissions entering the atmosphere from different sources.
However, air pollution is a major environmental risk to health. By reducing air pollution levels, we can help countries reduce the global burden of disease from respiratory infections, heart disease, and lung cancer. The lower the levels of air pollution in a city, the better respiratory (both long- and short-term), and cardiovascular health of the population will be.
A pollutant is the wrong stuff in the wrong place at the wrong time, and especially in developed nations such as ours, avoiding pollution is not necessarily easy. The problem is made worse by a loss of ownership of the problem; by reality gaps between government agencies which must regulate and monitor on the broader level of pollutant averages over time and local citizens that are justifiably upset over local episodes; and by entrenchment in the comfort of our own consumptive lifestyles and by limited alternatives.
The auto industry and its support enterprises continue to flourish, while mass transit struggles to survive. Fossil fuel-based energies overshadow wind, solar and other sources of energy. Cleaner fuels often remain a novelty. Land use decisions, or the lack of them, make it difficult for many to walk or bike to work. Numerous small mechanical devices replace muscle power. Disposable items save us even more time and work. Food is transported far from where it is grown, to a region which could supply its own food needs. All of these factors lead to increased product and energy consumption and have a vast impact on air quality.
Human activities release GHG emissions and contribute to increasing concentrations of GHGs in the atmosphere. CO2 is the predominant GHG emitted by human sources. Like most GHGs, CO2 is produced both by natural and human activities and can be removed from the atmosphere through natural processes. However, increased production of CO2 by human sources has caused total GHG emissions exceed natural absorption rates, resulting in increased atmospheric concentrations. Since the beginning of the industrial revolution, atmospheric concentrations of CO2 have increased by nearly 30 percent, CH4 concentrations have more than doubled, and N2O concentrations have risen by approximately 15 percent (Browning,2003).
Air pollution can affect our health in many ways with both short-term and long-term effects. Different groups of individuals are affected by air pollution in different ways. Some individuals are much more sensitive to pollutants than are others. Young children and elderly people often suffer more from the effects of air pollution. People with health problems such as asthma, heart and lung disease may also suffer more when the air is polluted. The extent to which an individual is harmed by air pollution usually depends on the total exposure to the damaging chemicals, i.e., the duration of exposure and the concentration of the chemicals must be taken into account. Examples of short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Other symptoms can include headaches, nausea, and allergic reactions. Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys. Continual exposure to air pollution affects the lungs of growing children and may aggravate or complicate medical conditions in the elderly.