Microbes and How It Affects Our Health

The quality of the air we breathe indoors has a significant impact on our health. Indoor environments often harbour airborne microbes such as bacteria, viruses, mould, mildew, and fungal spores. High concentrations of these contaminants have been linked to symptoms like headaches, dizziness, asthma, respiratory infections, and, in more severe cases, pneumonia or blood poisoning [World Health Organization, 2009; CDC, 2022].

Mould thrives in warm or damp conditions and can quickly release spores into the air, allowing it to spread throughout a space. Both mould and bacteria can travel on airborne particles and settle on surfaces, increasing the risk of exposure [Environmental Protection Agency, 2023].

What the Research Says About Air Quality
Studies on air quality reveal the following:

• Normal outdoor air contains between 50 and 600 bacteria and mould spores per 1,000 litres of air.
• Clean indoor air (e.g., from a maintained air conditioner) may contain 1,000 to 2,500 spores per 1,000 litres.
• Poor-quality indoor air, especially if musty or linked to health symptoms, often exceeds 2,500 spores per 1,000 litres.
• Outdoor air on windy days can contain over 25,000 spores per 1,000 litres.

Damp spaces, older homes, and tropical or humid climates are particularly prone to high microbial levels. A musty smell in a room or cupboard often indicates hidden mould growth—even if it’s not visible. Mould can colonise nearly any surface, including paint, glass, fabrics, and electronic devices.

Health Impact and Vulnerable Groups
Active mould can release mycotoxins, substances known to negatively affect health. Inhaled bacteria and spores may lodge in the airways, particularly in individuals with weakened immune systems or underlying respiratory conditions. These airborne contaminants are typically more concentrated near ground level, increasing the risk of exposure for babies and young children [WHO, 2009; Harvard T.H. Chan School of Public Health].

Maintaining clean indoor air isn't just about comfort—it's essential for protecting the health and wellbeing of your family.