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Ensuring Better Indoor Air Quality


During the winter season, as the Air Quality Index declines, the issue of Indoor Air Quality (IAQ) becomes a significant concern due to its potential adverse effects on occupants’ health. Despite the prevailing outdoor pollution, individuals often prefer staying indoors to avoid exposure to high pollution levels.


GS3- Environment- Pollution and Conservation

Mains Question:

Recognizing the health risks associated with poor Indoor Air Quality, develop an effective roadmap at the government and individual levels to minimise the rising phenomena of indoor air pollution. (10 Marks, 150 Words).

Indoor Air Pollution:

About Indoor Air Pollution:

  • The term “indoor air pollution” pertains to the introduction of dirt, dust, and gases into buildings, leading to contamination of the enclosed air.
  • It encompasses the examination of the physical, chemical, and biological characteristics of the air in indoor environments, be it in homes, institutions, or commercial facilities.
  • Indoor air pollution stems from various factors, both in rural and urban settings. This discrepancy arises because enclosed spaces facilitate the accumulation of potential contaminants more readily than open environments.
  • Numerous air pollutants, including NOx, SO2, ozone (O3), CO, volatile and semi-volatile organic compounds (VOCs), particulate matter (PM), radon, and microorganisms, have been identified within indoor spaces.

Causes of Indoor Air Pollution:

  • Some of these pollutants, such as NOx, SO2, O3, and PM, originate from external sources and are present in both indoor and outdoor settings.
  • Contrary to the common belief that indoor air is safe, many are surprised to learn that it can be up to 10 times more polluted than outdoor air, primarily due to inadequate ventilation in enclosed spaces.
  • In winter, when doors and windows are kept closed, the indoor air becomes trapped, leading to a rapid deterioration in air quality compared to the outdoor environment.
  • This problem is exacerbated in commercial and industrial spaces with complex structures, such as healthcare facilities, construction sites, factories, hotels, airports, and offices.
  • These settings often contain various indoor air pollutants, including volatile organic compounds (VOCs) from synthetic building materials, furnishings, and cleaning supplies, contributing to further degradation of indoor air.
  • Additionally, the presence of humidity fosters the growth of microorganisms like mold and mildew, resulting in musty odors and adversely affecting occupants’ well-being.

Impact of Indoor Air Pollution:

  • Poor Indoor Air Quality can lead to respiratory issues, eye irritation, headaches, fatigue, and other health conditions.
  • These air contaminants may exhibit radioactive, organic, inorganic, or even biological characteristics. In developing nations, indoor air pollution, also known as “household air pollution,” poses a significant health risk.
  • Inadequate ventilation may even cause ‘Sick Building Syndrome,’ negatively impacting overall health.
  • The State Of Global Air Report 2019 indicated that approximately 846 million individuals in India encountered household air pollution in 2017. This figure represents roughly 60% of the country’s population.

Improving the Indoor Air Quality:

  • Recognizing the health risks associated with poor IAQ, occupants must prioritize improving ventilation in enclosed spaces for enhanced public health.
  • Installing Heating, Ventilation and Air Conditioning systems can significantly contribute to achieving optimal ventilation by ensuring a continuous supply of fresh air throughout the building.

Heating, Ventilation and Air Conditioning:

  • HVAC, an acronym for Heating, Ventilation, and Air Conditioning, constitutes a series of technologies commonly employed to regulate room temperature, humidity, and ventilation within a specified area. Its purpose is to create a comfortable environment and maintain an acceptable standard of indoor air quality.
  • The design and implementation of HVAC systems fall under the domain of mechanical engineering.
  • The application of HVAC is rooted in the principles of thermodynamics, heat transfer, and fluid mechanics.
  • These systems find utility in both residential and industrial settings, necessitating a centralized mechanism for air conditioning, heating, and ventilation.
  • Key components integral to HVAC systems include:
  1. Heat exchanger
  2. Furnace chamber
  3. Condensing chamber
  4. Evaporator Coil
  5. Refrigerant Lines
  6. Ducts
  7. Vents
  8. Thermostat
  • These systems bring in fresh outdoor air to dilute indoor contaminants and filter pollutants from the incoming air while removing stale air from inside.
  • Moreover, HVAC systems offer thermal comfort by utilizing advanced desiccant technology to regulate indoor humidity. This helps maintain optimal relative humidity (RH), inhibiting the growth of microorganisms like mold and mildew.
  • The installation of advanced Energy Recovery systems, such as Enthalpy Wheels, facilitates efficient ventilation without compromising the air conditioning load, consequently reducing operational costs.


Equipped with honeycomb-designed chemical filters, HVAC systems can effectively remove gaseous contaminants from buildings. Considering the escalating impact of poor IAQ on health, alongside adopting HVAC systems, individuals should embrace Green Buildings. Utilizing green products in building construction strikes a balance between occupant comfort and reduced energy consumption, providing a sustainable approach to addressing IAQ concerns.

February 2024