HEALTH IMPACTS OF AIR POLLUTION

Pollutant Origin of Pollutant Effects
Sulphur dioxide industries, especially where coal or oil are used as fuel irritation of eyes, and respiratory system, increased mucus production, cough and shortness of breath
Carbon monoxide automobile exhaust and industries reduction in oxygen-carrying capacity of blood
Oxides of nitrogen automobile exhaust irritation of pulmonary tract affecting functioning of lungs
Hydrocarbons Chlorine automobile exhaust chloralkali industry lung cancer irritation of mucous membrane
Ammonia fertiliser industry, agriculture and in poultry farming irritation of mucous membrane
Hydrogen sulphide manufacture of coke, viscose rayon, distillation of tar and petroleum excessive inhalation leads to death
Acids and aldehydes chemical industries eyes, nose and throat irritation
Suspended particulate matter (SPM) industries, automobile exhaust respiratory diseases
Dust industries and automobile exhaust silicosis
Asbestos roofings, brake linings asbestosis
Lead automobile exhaust cumulative poison, impairment of central nervous system
Beryllium aerospace industry, hold appliances fatal to heart and manufacture of house- lungs
Manganese mining operations damages nerves and reproductive systems
Benzene automobile exhaust and manufacture of chemicals leukemia, chromosomal damage
Pesticides manufacture and application of pesticides depression; leads to death if inhaled in excess
Arsenic thermal power plants toxic

- Courtesy by : C.P.R.Environmental Education Centre, Chennai 

Health Effects on human beings

The human health effects of poor air quality are far reaching, but principally affect the body's respiratory system and the cardiovascular system.  Individual reactions to air pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, the individual's health status and genetics.  People who exercise outdoors, for example, on hot, smoggy days increase their exposure to pollutants in the air.

The health effects caused by air pollutants may range from subtle biochemical and physiological changes to difficulty breathing, wheezing, coughing and aggravation of existing respiratory and cardiac conditions. 

The air pollution mainly affects the following::

Human Respiratory System

The health of our lungs and entire respiratory system is affected by the quality of the air we breathe.  In addition to oxygen, this air contains other substances such as pollutants, which can be harmful.  Exposure to chemicals by inhalation can negatively affect our lungs and other organs in the body.  The respiratory system is particularly sensitive to air pollutants because much of it is made up of exposed membrane. 

Lung tissue cells can be injured directly by air pollutants such as ozone, metals and free radicals.  Ozone can damage the alveoli -- the individual air sacs in the lung where oxygen and carbon dioxide are exchanged. More specifically, airway tissues which are rich in bio-activation enzymes can transform organic pollutants into reactive metabolites and cause secondary lung injury.  Lung tissue has an abundant blood supply that can carry toxic substances and their metabolites to distant organs

Human Cardiovascular System

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 alterations that affect the rhythmicity and contractility of the heart.  If severe enough, functional changes may lead to lethal arrhythmias without major evidence of structural damage to the myocardium.

There also may be indirect actions secondary to changes in other organ systems, especially the central and autonomic nervous systems and selective actions of the endocrine system.  Some cytokines released from other inflamed organs may also produce adverse cardiovascular effects, such as reducing 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 critical to the preservation 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 have been associated with arrhythmias, and heart cell death.

Heart and Lung Diseases

Heart and lung illnesses and diseases are common in Canada, and there are many factors that can increase the chances of contracting them such as smoking and genetic predisposition.  The role of air pollution as the underlying cause remains unclear but is the subject of considerable research.  However, it is clear that air pollution, infections and allergies can exacerbate these conditions.  An early diagnosis can lead to appropriate treatment and ensure a normal or close to normal quality of life.  In many cases however, there is no cure and those affected may die prematurely.  The following are the most prevalent diseases: 

Minor Lung Illnesses - the common cold is the most familiar of these, with symptoms including sore throat, stuffy or runny nose, coughing and sometimes irritation of the eyes.

Lung Infections  - croup, bronchitis, and pneumonia are caused by viruses or bacteria and are very common. Symptoms may include cough, fever, chills and shortness of breath.

Asthma - is an increasingly common chronic disease among children and adults. It causes shortness of breath, coughing or wheezing or whistling in the chest. Asthma attacks can be triggered by a variety of factors including exercise, infection, pollen, allergies and stress.  It can also be triggered by a sensitivity to non-allergic types of pollutants present in the air such as smog.

Chronic Obstructive Pulmonary Disease (COPD) - is also known as chronic obstructive lung disease and encompasses two major disorders: emphysema and chronic bronchitis.  Emphysema is a chronic disorder in which the walls and elasticity of the alveoli are damaged.  Chronic bronchitis is characterized by inflammation of the cells lining the inside of bronchi, which increases the risk of infection and obstructs airflow in and out of the lung.  Smoking is responsible for approximately 80% of COPD cases while other forms of air pollution may also influence the development of these diseases.  Symptoms include cough, production of mucous and shortness of breath.  It is important to note that no cure exists for people suffering from COPD although healthy lifestyle and appropriate medication can help.

Lung Cancer - is the most common cause of death due to cancer in women and men. Cigarette smoke contains various carcinogens and is responsible for most cases of this often fatal disease.  The symptoms of lung cancer begin silently and then progress to chronic cough, wheezing and chest pain.  Air pollution has been linked somewhat weakly to lung cancer.

Coronary Artery Disease - refers to the narrowing or blocking of
the arteries or blood vessels that supply blood to the heart.  This disease includes angina and heart attack which share similar symptoms of pain or pressure in the chest.  Unlike angina, the symptoms caused by heart attack do not subside with rest and may cause permanent damage to the heart.  Smoking, lack of exercise, excess weight, high cholesterol levels in the blood, family history and high blood pressure are some of the factors that may contribute to this disease.

Heart Failure - is a condition in which the heart is unable to cope withits work load of pumping blood to the lungs and the rest of the body. The most common cause is severe coronary artery disease. The main symptoms are shortness of breath and swelling of the ankles and feet.

Heart-Rythm Problems - are irregular or abnormal rythms of the
heart beat. In some cases heart-rythm problems are caused by coronery artery disease. Symptoms of heart-rythm problems influttering in the chest (palpitation) and feeling light-headed. Some heart-rythm problems are life-threatening and need emergency treament.

Pyramid of Health Effects

Pyramid of Health Effects

The urban air pollution has worsened in most large cities in the developing world, a situation driven by population growth, industrialization, and increased vehicle use. Despite pollution control effects, air quality has approached the dangerous levels.

- Courtesy by : Air health effects division,Canada.

Effects on plants:
The air pollution affects the plants in the following ways

Effect on materials :
 

Effects on animals :

 

Health impact of specific air pollutants

Some of these gases can seriously and adversely affect the health of the population and should be given due attention by the concerned authority. The gases mentioned below are mainly outdoor air pollutants but some of them can and do occur indoor depending on the source and the circumstances.

Tobacco smoke. Tobacco smoke generates a wide range of harmful chemicals and is a major cause of ill health, as it is known to cause cancer, not only to the smoker but affecting passive smokers too. It is well-known that smoking affects the passive smoker (the person who is in the vicinity of a smoker and is not himself/herself a smoker) ranging from burning sensation in the eyes or nose, and throat irritation, to cancer, bronchitis, severe asthma, and a decrease in lung function.
Biological pollutants. These are mostly allergens that can cause asthma, hay fever, and other allergic diseases.
Volatile organic compounds. Volatile compounds can cause irritation of the eye, nose and throat. In severe cases there may be headaches, nausea, and loss of coordination. In the longer run, some of them are suspected to cause damage to the liver and other parts of the body.
Formaldehyde. Exposure causes irritation to the eyes, nose and may cause allergies in some people.
Lead. Prolonged exposure can cause damage to the nervous system, digestive problems, and in some cases cause cancer. It is especially hazardous to small children.
Radon. A radioactive gas that can accumulate inside the house, it originates from the rocks and soil under the house and its level is dominated by the outdoor air and also to some extent the other gases being emitted indoors. Exposure to this gas increases the risk of lung cancer.
Ozone. Exposure to this gas makes our eyes itch, burn, and water and it has also been associated with increase in respiratory disorders such as asthma. It lowers our resistance to colds and pneumonia.
Oxides of nitrogen. This gas can make children susceptible to respiratory diseases in the winters.
Carbon monoxide. CO (carbon monoxide) combines with hemoglobin to lessen the amount of oxygen that enters our blood through our lungs. The binding with other haeme proteins causes changes in the function of the affected organs such as the brain and the cardiovascular system, and also the developing fetus. It can impair our concentration, slow our reflexes, and make us confused and sleepy.
Sulphur dioxide. SO2 (sulphur-dioxide) in the air is caused due to the rise in combustion of fossil fuels. It can oxidize and form sulphuric acid mist. SO2 in the air leads to diseases of the lung and other lung disorders such as wheezing and shortness of breath. Long-term effects are more difficult to ascertain as SO2 exposure is often combined with that of SPM.
SPM (suspended particulate matter). Suspended matter consists of dust, fumes, mist and smoke. The main chemical component of SPM that is of major concern is lead, others being nickel, arsenic, and those present in diesel exhaust. These particles when breathed in, lodge in our lung tissues and cause lung damage and respiratory problems. The importance of SPM as a major pollutant needs special emphasis as a) it affects more people globally than any other pollutant on a continuing basis; b) there is more monitoring data available on this than any other pollutant; and c) more epidemiological evidence has been collected on the exposure to this than to any other pollutant.