Impacts of air pollution from vehicles
A. Environment
1. Smog
The term of smog was first used in 1905 by Dr H A Des Voeux to describe the conditions of fog that had soot or smoke in it. In fact the word smog has been created from a combination of the words fog and smoke. Smog is a combination of various gases with water vapor and dust. Burning fuels produce a large part of the gases that form smog. Smog forms when heat and sunlight react with these gases and fine particles in the air. Smog can affect remote suburbs and rural areas as well as big cities. Its occurrences are often linked to heavy traffic, high temperatures, and calm winds. During the winter, wind speeds are low and cause the smoke and fog to be stagnant; hence pollution levels can increase near ground level. This keeps the pollution close to the ground, right where people are breathing. It hampers visibility and harms the environment. Heavy smog greatly decreases ultraviolet radiation. In fact, in the early part of the 20th century, heavy smog in some parts of Europe resulted a decrease in the production of natural vitamin D leading to a rise in the cases of rickets.
The most harmful components of smog are ground-level ozone and fine airborne particles. Ground-level ozone forms when pollutants released from gasoline and diesel-powered vehicles and oil-based solvents react with heat and sunlight. It is harmful to humans, animals and plants, and causes difficult breathing condition.
The effects of smog on human health were obvious, especially when smog continued for several days. Many people suffered respiratory problems, and increased deaths were recorded, especially those relating to bronchial causes.
(taken from ‘Smog’, www.edugreen.teri.res.in, 2006)
A large scale of smog in Europe began in the 19th century when the industrial revolution happened. The presence of smog was mainly in England. The industries and the households used coal for heating and cooking in great number. Due to the burning of coal for heat during the winter months, emissions of smoke and sulfur dioxide were much greater in urban areas than they were during the summer months. Smoke particles trapped in the fog drew a yellow/black color on it and this smog often settled over cities for many days. The worst smog in England, called The Great London Smog lasted for five days and resulted in about 4,000 more deaths than usual. The occurrence of the Great London Smog made the government pass its first Clean Air Act in 1956, which was aimed to control domestic sources of smoke pollution by introducing smokeless zones. In addition, cleaner coals were introduced to reduce sulfur dioxide pollution. In the 1940s, severe smog began covering the city of Los Angeles in the USA.
2. Greenhouse Effect
Greenhouse Effect is a phenomenon where the sun heat, which the earth reserves, is trapped in the atmosphere. Naturally, CO2 in atmosphere blocks infra red light, which is bounced back by the earth, to make earth’s temperature warm since infra red brings heat energy. That process stabilizes the earth’s climate. But excessive CO2 and other harmful gases pollute the air and the heat cannot be released normally to the outer space resulting in global warming. The earth becomes hotter and hotter, and a lot of predicaments will happen.
There’re two major problems caused by greenhouse effect. They are flood and food shortage. The increasing temperature caused by green house effect will cause the melting of the ice in the north and south poles, and the sea will rise to a dangerous level. Most scientists agreed that will happen by 2030, when the earth temperature will have added about 1.5°-4°C. When that happens, a lot of problems will occur. There will be serious floods over many countries, people will lose their home and lands, and there will be serious problems with food supplies. When the climate changes, it will be very difficult to grow food since the weather will be either too dry or too wet. (Reading 2 LBPP LIA, page 59, 2003) Even now, global warming melts ice on Matternhorn Mountain Peak in Alp Mountain Range, Italy, draws land slippage that makes Italian routes up to the mountain have now been closed. (www.alternat-energy.net, July 29, 2006)
To reduce these negative effects, the using of fuel must be controlled and reforestation must be encouraged.
B. Humans
Air pollution gives bad impact to humans’ health. Poor air quality mostly affects the body’s respiratory system and the cardiovascular system, although it’s still not clear if air pollution is a primary cause of heart and lung illness. The reaction of pollutants to human body depends on the type of pollutant a person is exposed to, the degree of the exposure, a person’s health status and genetics. The health effects on the exposed person are ranged from subtle biochemical and physiological changes to difficulty breathing, wheezing, coughing and aggravation of existing respiratory and cardiac bad conditions. (www.hc-sc.gc.ca, May 15, 2006)
1. Respiratory System
The health of human respiratory system is affected by the quality of the air we breathe. Air contains of chemicals include oxygen, carbon monoxide, and a lot of harmful substances. When we inhale those hazardous substances, they will irritate and destroy the lung tissues. Toxic substances which expose the lung may be carried through blood stream to our entire body, thus they could affect the function of other organs. Some respiratory diseases which can be triggered or worsened by air pollution are Minor Lung Illnesses, lung infections, asthma, chronic obstructive pulmonary disease, and lung cancer. (www.hc-sc.gc.ca, May 15, 2006)
2. Cardiovascular System
Human cardiovascular system is also sensitive to air pollution. Arden Pope’s research on million adults participating in an American Cancer Society showed that more than two-thirds of deaths due to air pollution were deaths from heart disease. (Wolf, Vicki, 2006) The inhalation of air pollutants eventually leads to their absorption into the bloodstream and transport to the heart. A wide spectrum of chemical and biological substances may interact directly with the cardiovascular system to cause structural changes, such as degenerative necrosis and inflammatory reactions. Some pollutants may also directly cause functional changes that affect the rhythmicity and contractility of the heart. If severe enough, functional changes may lead to lethal arrhythmias without major indication of structural damage to the myocardium.
There also may be indirect actions to make changes in other organ systems, especially the central and autonomic nervous systems and selective actions of the endocrine system. Some cytokins released from other inflamed organs may also produce bad cardiovascular effects, such as the reducing in the mechanical performance and metabolic efficiency of the heart and blood vessels.
Many chemical substances may cause the formation of reactive oxygen. This oxidative metabolism is considered to be dangerous to the continuation of cardiovascular function. For example, oxygen free radicals oxidize low-density lipoproteins, and this reaction is thought to be involved in the formation of the atherosclerotic plaques. Oxidized low-density lipoproteins can injure blood vessel cells, and increase adherence and the migration of inflammatory cells to the injured area. The production of oxygen free radicals in heart tissues has been associated with arrhythmias, and heart cell death.
(taken from www.hc-sc.gc.ca, May 15, 2006)
