Air pollution threatens the health of humans and other living beings in our planet. It creates smog and acid rain, causes cancer and respiratory diseases.
The adverse health effects of air pollution are well established and have been reported in research studies for over 30 years. However, multiple variables make pinning down exact health outcomes to specific air pollution exposure very complicated. These variables include concentrations of air pollution and its various components, exposure time and individual response. For example, there is no specific health data available on air pollution exposure corresponding to length of an individual’s stay in any given location (say, for example an afternoon in Delhi? 2-4 years? A lifetime?) Nevertheless, there is much we do know and as scientific measurements become more sophisticated and evidence mounts, we gain better information about how air pollution and its various components affect our health. In March 2014 the World Health Organization reported that in 2012, seven million people died worldwide as a result of air pollution exposure. The finding more than doubled the WHO’s previous estimates on mortality due to air pollution exposure and placed air pollution as the world’s largest single environmental health risk.
What we know about air pollution and health. Some facts:
* Air pollution increases the risk of respiratory and heart disease.
* Both short and long term exposure to air pollutants have been associated to health impacts.
* People who are already ill are more severely impacted by air pollution.
* Children, the elderly and poor people are more susceptible to the harmful effects of air pollution.
* There is mounting evidence that exposure to air pollution has long-term effects on lung development in children. * Outdoor air pollution is carcinogenic
* Particulate matter (PM) is the component of air pollution that causes the most damage to human health
* Particulate matter in air pollution can cause a number of health problems and has been linked with illnesses and deaths from heart and lung disease. These effects have been associated with both short-term exposures (usually over 24 hours, but possibly as short as one hour) and long-term exposures (years). Groups particularly sensitive to particle pollution include people with heart or lung disease, older adults and children.
* Long-term exposures such as those experienced by people living for many years in areas with high particle levels, have been associated with problems such as reduced lung function and the development of chronic bronchitis and even premature death.
* Short-term exposures to particles (hours or days) can aggravate lung disease, causing asthma attacks and acute bronchitis, and may also increase susceptibility to respiratory infections. In people with heart disease, short-term exposures have been linked to heart attacks and arrhythmias. Healthy children and adults have not been reported to suffer serious effects from short-term exposures, although they may experience temporary minor irritation when particle levels are elevated.
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 haemoglobin 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 foetus. 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.