Air pollution is defined as the contamination of the air by tiny particles, or particulates, of solids and liquids and noxious gases in unhealthy amounts. It refers to the chemical and biological agents that modify the atmosphere, usually in perilous ways. Some of its major sources are automobile engines, industrial practices, heat and energy production, and the burning of solid waste. When inhaled, air pollutants affect the respiratory tract and lungs, but may also travel through the bloodstream and distress vital organs. By depositing themselves in the environment, these chemicals may also contaminate food and water, and they harm plants and animals alike. No one is safe from air pollution, and even your own home is full of airborne contaminants.
First, one naturally formed pollutant is carbon monoxide, a gas that is poisonous to humans. Unfortunately, it is tasteless, colorless, and odorless, so it cannot be detected by the senses.
Carbon monoxide's natural atmospheric concentration is about 0.2 ppm, or parts per million, which is not harmful to humans. Some of its natural sources are bushfires and volcanic eruptions; however, it is also formed by humans. The main indoor source of carbon monoxide is tobacco smoking, and the main outdoor source is vehicle exhaust and some industrial activities, like creating steel. Sydney, Australia's main source of this is automobiles; 91% of emissions are due to their combined exhaust.
There is significant reason why smoking is discouraged in pregnant women, those with heart trouble, and even the healthy. First, carbon monoxide affects humans by taking up hemoglobin's carrying space. This would otherwise be occupied by oxygen, and impairs vital organs by giving them less oxygen than is necessary. Also, a mere 2.5% or more affected hemoglobin will noticeably affect your health, and 40% will almost surely kill any human. Even small...