Why Indoor Air Can Be 5X More Polluted Than Outdoor Air

When most people think of air pollution, they picture smog over cities, busy roads, or factory chimneys. But the reality is that some of the most harmful air you breathe may actually be inside your own home, office, or school.

According to the U.S. Environmental Protection Agency (EPA) and multiple European health studies, indoor air can be two to five times more polluted than outdoor air. This hidden problem affects not just households, but also commercial environments where people spend the majority of their day.

What Makes Indoor Air So Polluted?

Unlike outdoor spaces, indoor environments trap pollutants and allow them to build up over time. Common sources include:

• Cooking fumes: Gas stoves and frying can release nitrogen dioxide (NO₂) and fine particles (PM2.5).

• Cleaning products: Many sprays and disinfectants release volatile organic compounds (VOCs).

• Furniture and materials: Carpets, paints, and upholstery can “off-gas” harmful chemicals like formaldehyde.

• Poor ventilation: Modern buildings are designed to be energy-efficient, which often means less airflow and more trapped pollutants.

Together, these sources create a cocktail of pollutants that are invisible but harmful when inhaled.

The Health Risks of Indoor Air Pollution

Exposure to polluted indoor air doesn’t always cause immediate symptoms, but the long-term effects can be severe.

Short-term effects:

• Headaches and fatigue

• Eye, nose, and throat irritation

• Worsening of asthma or allergy symptoms

Long-term effects:

• Chronic respiratory illnesses such as asthma and COPD

• Increased risk of heart disease and stroke

• Higher likelihood of certain cancers

The European Environment Agency estimates that poor air quality leads to over 300,000 premature deaths in Europe each year, with indoor exposure being a major contributing factor.

Why Monitoring Matters

The invisible nature of air pollution makes it difficult for individuals and businesses to act. Without data, people are left to assume that indoor spaces are safe, when in fact they may be breathing harmful levels of pollutants every day.

By making air quality visible, we can:

• Identify problem areas in homes and workplaces.

• Take targeted actions like improving ventilation or using air-purifying plants.

• Track improvements over time.

At PurerAir, our mission is to empower individuals and organisations with transparent and reliable indoor air quality data. By combining decentralised science (DeSci) and blockchain technology, we aim to ensure that environmental data is open, trustworthy, and owned by the community — not hidden in centralised systems.

Taking Action

Improving indoor air quality doesn’t have to be overwhelming. Simple steps such as ventilating rooms regularly, limiting harsh cleaning products, and adding air-purifying plants can make a difference. But the most powerful step is awareness: knowing what’s in the air you breathe.

With transparent data and community-driven science, we can transform indoor environments from hidden risks into healthier spaces for everyone.