CHAPTER ONE
INTRODUCTION
a.Background to the Study
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.
Apollutant 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.
Environmental pollution is the unfavourable alteration of the environment due to the addition of impurities by man to constitute danger to either his/her health (ldodo-Umeh, 2010). One of the major causes of environmental pollution is air pollution. Air pollution is the additional of air borne substances such as dust, smoke, soot and sulphurdioxide found in the air that alter the composition of the atmosphere causing harm to human. Carbon monoxide is the major pollutant produced from the exhaust of automobile. Nitrogen-monoxide and Nitrogen dioxide are other gases produced from the motorcycle (ldodo-Umeh, 2010).
Although transportation is a vital part of the economy and is essential for everyday activities, it is also a significant source of greenhouse gas (GHG) emissions. Greenhouse gases (GHGs) occur naturally in the earth’s atmosphere and help to keep the planet hospitable to life by trapping some of the sun’s natural heat. Without this “greenhouse effect,” the earth’s average surface temperature would be about 33 degrees Celsius cooler than it is currently.  The most important naturally occurring GHGs associated with this phenomenon are water vapor (H2O), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
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).