Introduction

Indoor air pollution remains largely unmonitored and unregulated in India despite high exposure levels. Pollutants from construction dust, household fuels, cleaning agents, and aromatic disinfectants accumulate indoors and degrade air quality. Recognising this, researchers from BITS Pilani have developed India’s first IAQ scale (Indoor Air Quality scale), capable of measuring multiple indoor pollutants and providing a health-based score for residential and commercial buildings.

Their findings published in the Royal Society of Chemistry Journal establish benzene as the most dangerous indoor pollutant and call for inclusion of IAQ standards in building codes and smart city frameworks.

Why in the News?

This is the first India-specific scientific model for assessing indoor air pollution beyond the conventional AQI framework.

1. First-of-its-kind IAQ Scale: Developed by BITS Pilani researchers, enabling precise measurement of multiple indoor pollutants.
2. Major Data Insight: Indoor air can be two to five times more polluted than outdoor air.
3. Policy Gap: There are no formal regulations or monitoring frameworks for indoor air quality in India.
4. Health Implications: The study links poor IAQ to headaches, fatigue, respiratory diseases, and cardiovascular risks, especially in women and infants.
5. Call to Action: The research advocates IAQ standards in building codes and smart city designs, a potential policy game changer.

Understanding the New Indoor Air Quality (IAQ) Scale

1. Comprehensive Measurement: Unlike air purifiers, which track only particulate matter and humidity, the IAQ scale captures a wider range of pollutants including PM2.5, PM10, CO, benzene, and volatile organic compounds (VOCs).
2. Pan-India Modelling: The model integrates Indian demographic data, age groups, geography, income, and housing patterns, to derive a weighted IAQ score.
3. Weighted Parameters: Exposure time (25.9%), ventilation efficiency (9.8%), and enclosure size (4.4%) form key components of the health-based index.
4. Scoring System: IAQ scores range from 22 (severe pollution) to 100 (healthy indoor air).

Health Implications of Poor Indoor Air Quality

1. Sick Building Syndrome: Poor IAQ triggers headaches, fatigue, and irritation, often observed in modern buildings with poor ventilation.
2. Chronic Diseases: Prolonged exposure causes asthma, COPD, bronchial allergies, and cardiovascular disorders.
3. High-Risk Groups: Women and infants face higher vulnerability due to longer indoor exposure and cooking-related emissions.
4. Toxic Emissions: Indoor combustion from fuels, incense, and construction residues increases carbon monoxide and benzene concentration.

Major Pollutants of Concern

• Benzene:

1. 1. Most dangerous indoor pollutant identified in the study.
   2. Emitted by aromatic disinfectants, fuels, and solvents.
   3. Long-term exposure is linked to leukaemia, anaemia, and cancer.
   4. Recognised carcinogen by the World Health Organisation (WHO).

• Carbon Monoxide (CO):

1. 1. Generated from gas stoves, oil-burning furnaces, and charcoal grills.
   2. Causes poisoning and oxygen deprivation.
   3. Accumulates in poorly ventilated rooms, leading to long-term toxicity.

Unexpected Sources and Indoor Traps

1. Aromatic Disinfectants: Release benzene and toxic VOCs during use.
2. Incomplete Combustion: Burning incense sticks in closed rooms emits carbon monoxide.
3. Organic Waste Decay: Produces methane and foul-smelling gases; methane is 80 times more potent than carbon dioxide over 20 years.
4. Poor Waste Segregation: Creates landfill-like conditions indoors, compounding toxicity.

Simple Household Interventions for Cleaner Indoor Air

1. Enhanced Ventilation: Open windows during low-pollution hours and use exhaust fans while cooking.
2. Segregation of Waste: Keep dry and wet waste separate to prevent methane buildup.
3. Regulated Burning: Reduce incense burning and switch to non-toxic cleaning products.
4. Natural Fresheners: Avoid synthetic air fresheners; use herbal or essential oil-based alternatives.
5. Lifestyle Measures: Routine cleaning, minimal use of chemical cleaners, and proper ventilation improve long-term air quality.

Conclusion

Indoor air pollution, though invisible, represents one of the most persistent and under-addressed public health risks in India. The IAQ scale developed by BITS Pilani researchers provides a data-backed pathway to integrate indoor air monitoring into policy, urban design, and smart city missions. Addressing this silent crisis through ventilation norms, IAQ regulations, and public awareness will mark a major leap toward holistic environmental governance and citizen well-being.

PYQ Relevance

[UPSC 2021] Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What changes in India’s National Clean Air Programme are required to achieve these revised standards?

Linkage: The WHO’s revised AQGs (2021) set stricter limits for PM 2.5 and NO2, highlighting the need for India’s NCAP to adopt health-based indoor and outdoor air quality standards, aligning with the emerging Indoor Air Quality (IAQ) scale developed by BITS Pilani.

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