Context-Recently According to Centre for Science and Environment’s (CSE’s) air pollution analysis, the three-year average levels of PM 2.5—atmospheric particulate matter with a diameter of less than 2.5 microns—during 2016-18 were 25% lower than the 2011-14 baseline (three-year average).

• Though the number of days with severe PM 2.5 levels has come down since 2015, the CSE says Delhi still needs to cut pollution levels by 65% to meet global air quality standards.

• According to the State Of Global Air Report 2019, published earlier this year by the Boston-based Health Effects Institute, an independent global health and air pollution research organization, an estimated 846 million people in India were exposed to household air pollution in 2017. That’s 60% of the country’s population.

Indoor air pollution

kitchen.

• While a modern kitchen doesn’t use solid fuels, even gas burners and cooking methods affect air quality. A June 2018 study and experiment  found that “cooking, cleaning and other routine household activities generate significant levels of volatile and particulate chemicals inside the average home, leading to indoor air quality levels on par with a polluted major city". Much of this would be relevant in an Indian setting too

primary gases (emitted directly from sources)

• In a typical indoor environment, primary sources would include “the building itself (e.g. wood, linoleum, plastics), consumer products (e.g. personal care products, cleaning or cooking products, equipment and office products, off-gassing from items brought into the home), microbial and human metabolic emissions, occupant activities (e.g. cooking)", and entry of outdoor air into the house, through openings, ventilation systems or leaks.

Secondary gases( produced through chemical reactions in the air.)

•  For e.g, cooking releases a large amount of VOCs (Volatile Organic Compounds), CO2 (Carbon Dioxide), NOx (Nitrogen Oxide) and other particles. VOCs and NOx react in the presence of sunlight to form ozone.

Threat

• Ozone (O3): Exposure to ground-level ozone increases a person’s likelihood of dying from respiratory disease, specifically cardiovascular disease
• PM 2.5: In 2017, exposure to PM 2.5 was the third leading risk factor for type 2 diabetes-related deaths and disability
• Nitrogen oxide (NOx): NOx can cause inflammation of the airways. Long-term exposure can diminish lung function and increase susceptibility to allergens
• Cigarettes, mosquito coils: Particulate matter from burning in a closed indoor environment can lead to illness (cardiovascular and respiratory diseases) following prolonged exposure

Sick building syndrome (New concept)

• The SBS is the situation in which the inhabitant of a building experience some health problems that are directly related to the building environment. This feeling of health problems resulted into the sickness and also productivity losses to the people working in them.

ORIGIN OF SBS:

• Poor ventilation– The unpleasant smells and moisture, is not going into  outside air, and this it keeps interior of building not circulated and stagnation of the indoor air happened.
• Poor IAQ – The poor ventilation, heating and air-conditioning systems, dampness and moisture damage due to leaks, overflow or high humidity. Various inhabitants activities, such as construction or remodelling or Indoor and outdoor contaminated air can cause poor IAQ.
• Using volatile organic compounds, including formaldehyde, cleaning products, and manufactured plastic and wood products
• External contaminants – outside air entering a building

To AVOID SBS use Indoor Air Purifiers:

• There are few ways to avoid SBS completely are to design and construct a building with good indoor air quality at the time of planning a building.
• Use of low emitting building materials, proper location of outlet and much more.
• For already constructed building we recommend opening the windows/doors for an hour or so to circulate/ventilate the indoors with the outside air