Why in News ?
- A research team from BITS Pilani Hyderabad’s MMNE Lab, led by Prof. Sankar Ganesh and Dr. Arun Roy Choudhury, has developed India’s first customised Indoor Air Quality (IAQ) scale.
- The device aims to measure key indoor air pollutants and assign a numerical score, similar to the outdoor Air Quality Index (AQI), to assess indoor air safety.
- The findings were published in the Royal Society of Chemistry journal, highlighting the urgent need to include indoor air standards in building codes and smart cities.
Relevance:
GS 3 – Environment, Science & Technology, Health
• Indoor air pollution and public health impacts
• Innovation in environmental monitoring (AI-based sensor models)
• Air quality standards and smart city integration
• Sustainable urban development and building codes
• Linkages to SDG 3 (Health) & SDG 11 (Sustainable Cities)
Background
- While outdoor air pollution gets wide attention, indoor air can be 2–10 times more polluted, according to WHO and environmental studies.
- Urban India’s closed, poorly ventilated environments worsen the situation, especially in winters.
- Currently, India lacks a standardised Indoor AQI framework, unlike the US, UK, and EU which already have IAQ norms.
What is the Indoor Air Quality (IAQ) Scale?
- A quantitative index similar to the outdoor AQI but designed for indoor environments such as homes, offices, and classrooms.
- Developed through AI-based modelling considering:
- Pollutant concentration (59.5%)
- Exposure time (25.9%)
- Ventilation efficiency (9.8%)
- Enclosure size (4.4%)
- Generates a score from 22 to 100, with 22 being the most severe and 100 the best quality.
Major Indoor Pollutants Identified
| Pollutant | Source | Health Impact |
| Benzene | Paints, solvents, cleaning agents, fuels | Carcinogenic; damages blood and immune system |
| Carbon monoxide (CO) | Incomplete combustion (stoves, incense) | Reduces oxygen supply; causes headaches, fatigue |
| PM2.5 and PM10 | Dust, cooking smoke, building materials | Respiratory and cardiovascular diseases |
| Volatile Organic Compounds (VOCs) | Paints, furniture, cleaning agents | Neurological and hormonal impacts |
| Methane | Organic waste decay | Potent greenhouse gas; affects indoor oxygen levels |
Key Findings
- Indoor PM2.5 and PM10 levels can exceed outdoor safe limits due to poor ventilation and frequent cooking/cleaning.
- Seasonal fluctuations: Winter months show higher toxicity as households remain closed.
- Benzene emerged as India’s most dangerous indoor pollutant, linked to cancer and birth defects.
- Carbon monoxide levels rise due to incense burning and disinfectant misuse.
- Construction materials and poor ventilation amplify pollution accumulation indoors.
India’s First Indoor AQI Model — How It Differs from Air Purifiers
- Air purifiers only detect particulate matter and humidity.
- IAQ scale measures multiple pollutant categories (PM, CO, VOCs, Benzene, etc.), exposure time, and ventilation data.
- Offers context-specific measurement for India’s dense housing, varied climates, and mixed pollution sources.
- Meant for public use once commercialised — IP registration is in process.
Why Indoor Air Quality Matters ?
- WHO estimates >3.2 million annual deaths globally due to household air pollution.
- India: Over 700,000 deaths annually linked to indoor air pollution (IHME, 2023).
- Vulnerable groups: Children, elderly, pregnant women, and those with pre-existing respiratory issues.
Health Impacts
- Short-term: Headaches, dizziness, fatigue, irritation of eyes/nose/throat.
- Long-term:
- Respiratory diseases (asthma, COPD, bronchitis)
- Cardiovascular ailments
- Neurological disorders (due to VOCs and benzene exposure)
- Cancers linked to chronic exposure to benzene and formaldehyde.
Major Sources of Indoor Pollution
- Cooking and heating using biomass, charcoal, or kerosene.
- Cleaning products, disinfectants, synthetic fragrances.
- Construction dust, paints, and adhesives.
- Tobacco smoke and vehicle emissions entering from outdoors.
- Poor waste management, causing methane accumulation indoors.
What Can Households Do?
- Improve cross ventilation and use exhaust fans.
- Avoid synthetic air fresheners; use natural cleaning agents.
- Segregate and compost organic waste.
- Introduce indoor greenery (e.g., money plant, areca palm).
- Prefer low-VOC paints and avoid excessive incense burning.
Policy and Research Implications
- Inclusion of IAQ standards in National Building Code and Smart City guidelines.
- Integrate IAQ sensors in urban monitoring networks.
- Incentivise eco-friendly building materials and natural ventilation designs.
- Promote public awareness through government campaigns.
- Encourage research and innovation under ‘Make in India for Health’ and National Clean Air Programme (NCAP).
Broader Context and Global Best Practices
- U.S. EPA and EU use detailed IAQ indices covering 10+ pollutants.
- Singapore mandates indoor air audits in public buildings.
- China links IAQ norms with green building certification.
- India’s new IAQ framework could align with SDG 3 (Health) and SDG 11 (Sustainable Cities).
Conclusion
- The BITS Hyderabad Indoor AQI scale is a pathbreaking initiative bridging a critical policy gap.
- With India urbanising rapidly, indoor air quality will define public health outcomes as much as outdoor pollution.
- The next step lies in national adoption, standardisation, and citizen-level awareness to ensure every home breathes clean air.
