Description
Indoor air pollution and its impact
Indoor air pollution refers to the occurrence of contaminants within a home, workplace (or other inhabited enclosure) arising from such sources as fuel combustion for heating or cooking; from stored substances, furnishings and carpeting; or from the particular geology (underlying rocks) of an area.
As cited by the Indian Council of Medical Research (ICMR) Bulletin, the report of the World Health organization (WHO) emphasizes the ‘rule of 1000’ which states that when a pollutant is released indoors, it is one thousand times more likely to reach people’s lungs than a pollutant released outdoors. More than 1.6 million people, mainly women and children, die prematurely each year after breathing high levels of indoor smoke. This represents approximately twice the estimated mortality due to outdoor pollution. Children and senior citizens can be more vulnerable to indoor pollution because their immunity may be compromised.
Key facts
• Around 3 billion people cook and heat their homes using open fires and simple stoves burning biomass (wood, animal dung and crop waste) and coal.
• Over 4 million people die prematurely from illness attributable to the household air pollution from cooking with solid fuels.
• More than 50% of premature deaths among children under 5 are due to pneumonia caused by particulate matter (soot) inhaled from household air pollution.
• 3.8 million premature deaths annually from non-communicable diseases including stroke, ischaemic heart disease, chronic obstructive pulmonary disease (COPD) and lung cancer are attributed to exposure to household air pollution.
Sources of Indoor Pollution
Among all the indoor air pollutants, persistent organic pollutants (POPs) persist in the environmental media and are extremely lethal even in small amounts. Exposure to POPs is recognized as an important environmental risk factor for humans causing cancer, nervous system damages, reproductive and immune system impairments. Once released from the sources, they can remain unaltered and persist in the environment for long periods because of their extensive half-life.
Biological contaminants like bacteria, molds, viruses and yeasts are usually found in moist indoor environments. They can also act as human pathogens. Their potential health effects include allergies, irritation and sensitivity and toxicity.
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Indoor pollutant
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Major sources
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Carbon monoxide
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Fuel/tobacco combustion
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Fine particles
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Fuel/tobacco combustion, cleaning, fumes
from cooking oil
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Nitrogen oxides
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Fuel combustion
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Sulfur oxides
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Coal combustion
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Arsenic and fluorine
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Coal combustion
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Volatile and semi-volatile
organic compounds
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Fuel/tobacco combustion, furnishings,
construction materials, fumes from cooking, consumer products
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Aldehydes
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Furnishing, construction materials,
cooking
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Pesticides
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Consumer products, dust from outside
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Asbestos
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Wear or demolition of construction
materials
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Lead
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Wear of painted surfaces
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Biological pollutants
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Moist areas, ventilation systems,
furnishings
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Radon
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Soil under buildings, construction
materials
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Ozone
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Photocopier, printers
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Persistent organic pollutants (POPs)
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Cables, computers, TVs and household
textiles
Fuel/tobacco combustion, fumes from
food, e.g. from cooking oil
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Impacts on health
a) PneumoniaExposure to household air pollution almost doubles the risk for childhood pneumonia.
b) StrokeNearly one quarter of all premature deaths due to stroke (i.e. about 1.4 million deaths of which half are in women) can be attributed to the chronic exposure to household air pollution caused by cooking with solid fuels.
c) Ischaemic heart diseaseApproximately 15% of all deaths due to ischaemic heart disease, accounting for over a million premature deaths annually, can be attributed to exposure to household air pollution.
d) Chronic obstructive pulmonary diseaseOver one third of premature deaths from chronic obstructive pulmonary disease (COPD) in adults in low- and middle-income countries are due to exposure to household air pollution. Women exposed to high levels of indoor smoke are 2.3 times as likely to suffer from COPD than women who use cleaner fuels. Among men (who already have a heightened risk of COPD due to their higher rates of smoking), exposure to indoor smoke nearly doubles (i.e. 1.9) that risk.
e) Lung cancerApproximately 17% of annual premature lung cancer deaths in adults are attributable to exposure to carcinogens from household air pollution caused by cooking with solid fuels like wood, charcoal or coal. The risk for women is higher, due to their role in food preparation.
Other impacts
a) The use of polluting fuels also poses a major burden on sustainable developmentb) Fuel gathering consumes considerable time for women and children, limiting other productive activities (e.g. income generation) and taking children away from school. In less secure environments, women and children are at risk of injury and violence during fuel gathering.c) Black carbon (sooty particles) and methane emitted by inefficient stove combustion are powerful climate change pollutants.d) The lack of access to electricity for at least 1.2 billion people (many of whom then use kerosene lamps for lighting) creates other health risks, e.g. burns, injuries and poisonings from fuel ingestion, as well as constraining other opportunities for health and development, e.g. studying or engaging in small crafts and trades, which require adequate lighting.
Basic approaches to eliminate indoor air pollution include:
a) Source control (a preventive technique; for example, banning smoking in public areas) and source isolation (when source cannot be removed; for instance, separate venting of bathrooms); b) Increased ventilation and dehumidification to facilitate the reduction of microbial growth. However, indoor pollution may be decreased by properly identifying and eradicating the sources.
Measures to control indoor air pollution can be summed up as:
a) Educating the public: Public education is valuable in preventing illnesses resulting from combustion of biomass fuels to ensure awareness of the long-term health effects of indoor air pollution. Also, awareness campaigns should be organized in schools and villages so that the most vulnerable populations (that is, the elderly, women and children) can be targeted.
b) Choice of fuel: The choice of fuel for domestic energy can be associated with such factors as availability of fuel, affordability and habit of the user. Around 50% of people in developing nations rely on coal and biomass for energy requirements.
c) Cooking stove: Incomplete combustion due to inadequate design of the stove leads to enormous emissions. Efforts should be made to modify stove designs to make them fuel efficient and provide them with a ventilation mechanism (e.g. chimney) to remove pollutants from the indoor environment.
d) Ventilation: Ventilation ensures mixing of the outside air with indoor environment to reduce accumulation of indoor pollutants.
e) Elimination of the sources of microbial contaminants: Regular clean-up and repair of all areas where water leakage has occurred including floors, roofs and drains helps to ensure removal of microbial habitats. Feathered pets should be restricted to less occupied parts of the home. Washing cats and dogs can reduce allergen levels for a few days.
