Indoor Air Pollution

Indoor air pollution in India has become a serious and growing concern which is alarming considering that urban residents in India spend 70% to 90% of their time indoors.

About Indoor Air Pollution

Indoor air pollution is created by the release of harmful pollutants inside. These can include fine particulate matter (PM), carbon monoxide and various other toxins.

Magnitude of indoor Air Pollution

Around 2.1 billion people worldwide (around a third of the global population) cook using open fires or inefficient stoves fuelled by kerosene, biomass (wood, animal dung and crop waste) and coal, which generates harmful household air pollution.
Household air pollution was responsible for an estimated 3.2 million deaths per year in 2020, including over 237 000 deaths of children under the age of 5.
The combined effects of ambient air pollution and household air pollution are associated with 6.7 million premature deaths annually.

Indoor Air Quality (IAQ) refers to the quality of air within and around buildings, and it significantly impacts the health and comfort of occupants.
In India, indoor pollution sources are both internal (originating inside buildings) and external (outdoor pollutants infiltrating indoors).
Poor insulation in buildings allows outdoor pollutants to infiltrate indoor spaces, and activities within buildings themselves also contribute to the deterioration of indoor air quality (IAQ).
While outdoor air pollution has received significant attention, the same urgency has not been extended to indoor environments.

Different Sources of Indoor Air Pollution

Source Type	Pollutant/Chemical	Impact on Health
Combustion	Carbon monoxide, smoke	Headaches, dizziness, respiratory issues, heart disease
Building Materials	Asbestos, formaldehyde, lead	Cancer, developmental disorders, respiratory problems
Biological	Mould, allergens	Allergies, asthma, respiratory infections
Household Activities	Pesticides, chemical cleaners, incense smoke	Toxic exposure, irritation of eyes/nose/throat, cancer
Outdoor Infiltration	Particulate matter, ambient air pollutants	Respiratory and cardiovascular diseases, cancer
Natural Radiation	Radon gas	Increased risk of lung cancer
Furniture and Decor	Benzene, Volatile organic compounds (VOCs) from paints, varnishes, adhesives	Eye, skin, and respiratory irritation, long-term cancer risk

Impact of Indoor Air Pollution

Immediate Health Effects

Irritation of Eyes, Nose, and Throat: Exposure to pollutants can cause discomfort and irritation.
Headaches, Dizziness, and Fatigue: Poor indoor air can lead to short-term symptoms resembling viral illnesses.

Long-Term Health Effects

Respiratory Diseases: Chronic exposure can lead to conditions such as asthma, chronic obstructive pulmonary disease (COPD), and lung infections.
Heart Disease: Pollutants contribute to cardiovascular stress and related illnesses.
Cancer: Exposure to carcinogenic substances like asbestos, radon, and formaldehyde increases cancer risk.
Cognitive Impairment: Studies show poor IAQ can significantly reduce cognitive function and productivity.

Policy and Regulations on Indoor Air Quality

Regulatory Bodies: Key agencies like the Central Pollution Control Board (CPCB), Bureau of Indian Standards (BIS), National Building Code (NBC), and State Pollution Control Boards (SPCBs) regulate IAQ standards, ensuring clean and healthy indoor environments.
Building Codes and Compliance: Construction must adhere to the National Building Code (NBC) for IAQ, with regular air quality monitoring and the use of low-VOC materials.
Enforcement: IAQ standards are enforced through inspections, penalties, awareness drives, and, in severe cases, legal actions like sealing of non-compliant buildings.

Standard Levels for Indoor Air Quality in India

Parameter	Standard Limit	Duration
PM2.5	40 µg/m³	24-hour average
PM10	60 µg/m³	24-hour average
Carbon Monoxide (CO)	2.0 mg/m³	8-hour average
Formaldehyde (HCHO)	0.05 ppm	30-minute average
Carbon Dioxide (CO₂)	No specific limit (below 1000 ppm recommended)	Continuous
Temperature	24°C – 30°C	Comfort Range
Relative Humidity	30% – 60%	Comfort Range

Challenges in Tackling Indoor Pollution

Lack of Attention: Indoor air pollution often receives less focus compared to outdoor pollution, despite people spending nearly 90% of their time indoors.
Old Construction: Many existing buildings in India have poor insulation and ventilation systems, making retrofitting costly and technically challenging.
Overcrowded Cities: High urban population densities lead to cramped living spaces with inadequate air circulation, amplifying indoor pollutant buildup.
Limited Public Awareness: People are often unaware of indoor air hazards like formaldehyde or radon, delaying preventive measures or timely interventions.
Economic Constraints: Implementing healthy building practices can still be perceived as expensive, discouraging widespread adoption, especially in low-income housing.

Ways to Mitigate Indoor Air Pollution

Improving Building Ventilation: Design for cross-ventilation, use HEPA(high efficiency particulate air) filters, and incorporate skylights and open corridors to boost airflow and light.
- HEPA filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm)
Material and Furnishing Choices: Select low-VOC materials and strictly avoid asbestos and lead-based products for healthier indoor environments.
Building and Retrofitting Strategies: Prioritize air quality in new designs and retrofit existing buildings with better insulation and toxin-free materials.
Indoor Environment Management: Reduce indoor pollutants, introduce houseplants, and ensure effective waste disposal to maintain cleaner indoor air.
Special Considerations for Air-Conditioned Spaces: Separate zones, enhance air circulation, and use easy-to-clean surfaces to sustain healthier air in AC environments.
Simple Practices for Homes: Regularly ventilate with open windows and allow sunlight in to naturally disinfect and refresh indoor spaces.

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