Indoor Air Quality Standards In The Making

Poor indoor air quality, a major cause of death and respiratory diseases, affects countries of all income levels. Greater awareness of its adverse health impacts is leading governments to mull strategies to tackle the problem.

Major sources of particles and gases affecting indoor air quality include combustion of fuels such as oil, gas and wood as well as building materials, household products containing chemicals, tobacco smoke, radon and air pollutants from outside.

The World Health Organisation (WHO) estimates that worldwide around 1.5 million deaths per year - mostly women and children in developing countries - are attributable to indoor combustion of solid fuels.

The problem is not limited to developing countries. In the EU combustion, chemicals from building materials and dampness lead to annual losses of over two million years of healthy life due to premature death or chronic diseases, like asthma and cardiovascular diseases, according to the WHO.

In 2003, the European Commission’s Joint Research Centre found that indoor concentrations of dangerous air pollutants in cities are often much higher than outdoors, posing a significant health hazard as Europeans spend around 90% of their time indoors. It estimated that up to 20% of Europeans suffer from asthma and other allergic diseases caused by substances typically found in indoor environments, while indoor pollutants like tobacco smoke, radon, asbestos and benzene contribute to substantial increases in cancer cases.

The problem is exacerbated by reducing ventilation rates to limit energy consumption and extensive use of new building materials that release chemical substances, the JRC explained.

Concerned about public health, governments are increasingly starting to seek strategies for improving air quality. Measures include restricting pollution sources (e.g. by switching to cleaner energy alternatives, like gas or renewable energy, or improving stoves), improving ventilation and using air cleaners.

For example, the US Environmental Protection Agency developed the " Tools for Schools " programme to reduce exposure to indoor environmental contaminants in schools.

To help governments, the World Health Organisation is currently preparing the first comprehensive guidelines on indoor air quality standards to tackle health hazards. This involves addressing selected chemicals, combustion products, and dampness and mould.

Air quality guidelines have traditionally been presented as acceptable concentration levels of specified pollutants. But the WHO decided that for indoor air quality, the inclusion of biological agents and combustion-related problems warranted broadening the approach to include recommendations based on qualitative indicators, like damp in building structures - which leads to microbial growth - alongside health-based recommendations for concentration values.

The WHO published its first guidelines for addressing dampness and mould in 2009. They seek to reduce health risks caused by dampness and microbial contamination, which provided objectives for indoor air quality management but stopped short of telling governments how to achieve them, as appropriate actions depend on local conditions.

The guidelines stress that moisture and microbial growth can be controlled by designing and maintaining building envelopes appropriately to prevent thermal bridges and the entry of water. In addition, temperature control and ventilation help prevent excess humidity and surface condensation, they stressed.