Context

India’s poor indoor air quality can impair cognitive development in children under two years — when brain growth is at its peak, according to a study.

What is indoor air pollution? Which air pollutants exist indoor?

• It refers to the physical, chemical, and biological characteristics of air in the indoor environment within a home, building, or an institution or commercial facility. 
• A number of air pollutants have been recognised to exist indoors, including NOx, SO2, ozone (O3), CO, volatile and semi-volatile organic compounds (VOCs), PM, radon and microorganisms.
• Some of these pollutants (NOx, SO2, O3, and PM) are common to both indoor and outdoor environments and some of them may originate from outdoors.
• These air pollutants can be inorganic, organic, biological or even radioactive.

What factors affect indoor air quality?

• Indoor air quality is affected by many factors, including:
• Type and running conditions of indoor pollution sources
• Ventilation conditions: Air pollutants may accumulate in the indoor environment if the indoor air is not well ventilated, which seriously affects the health of the inhabitants.
• Indoor activities (cooking with dirty fuel): According to the World Health Organization (WHO), around three billion people, mostly women in the villages of India and in other parts of the world still cook and heat their homes using dirty solid fuels.
• These include waste wood, charcoal, coal, dung and abundantly available crop wastes. These are burnt on open fireplaces, cooking stoves etc.
• This generates a large amount of air pollutants such as
  • sulphur dioxide (SO2
  • nitrous oxides (NOx)
  • carbon monoxide (CO)
  • particulate matter (PM)

Effects of indoor air pollution

The effect of these air pollutants on humans depends on their toxicity, concentration and exposure time and may vary from person to person.

• Sick building syndrome (SBS): The most common effect is called sick building syndrome (SBS), in which people experience uncomfortable or acute health effects such as irritation of nose, eyes and throat, skin ailments, allergies and so on.
• Premature deaths: The WHO fact sheet on household air pollution due to indoor pollutants states that 3.8 million premature deaths occur annually.
  • These include stroke, ischaemic heart diseases, chronic obstructive pulmonary diseases and lung cancer, all of which are attributed to exposure to household air pollution.