You are here: Home Page > Air Quality > Research: Many air pollutants are higher indoors than outdoors

Research: Many air pollutants are higher indoors than outdoors

Levels of many harmful air pollutants are higher indoors than outdoors, according to new research conducted within the European Union, released this week (8th February).

These latest findings, which identify the main polluters and map their geographical distribution, come from the European Indoor Air Monitoring and Exposure Assessment Project (AIRMEX), an EU funded project. The importance of the health impacts of indoor air pollution is officially recognised in the European Environment and Health Action Plan (EHAP) – a strategy which is designed to give the EU the scientific information to reduce the adverse health impacts of environmental factors and to endorse better cooperation between actors in the environment, health and research fields.

The AIRMEX study monitored indoor, outdoor and individual exposure to selected chemical compounds across the EU. The researchers found that levels of many harmful air pollutants are greater indoors than outdoors, and even higher when measured on the individual themselves. The levels of the chemical compound benzene – a known carcinogen - were found to be worryingly high and indicate higher exposure than what is normally expected with the annual EU limit values for ambient air quality.

The study examined the impact of mixtures of chemicals on human lung cells. Results indicate that chemical compounds interact and the effects on human health will alter depending on the other chemicals present. The findings suggest that the multiple affects of indoor air pollutants depends on other factors unique to the individual, such as gender, stress, and genetic background.

Directive 2000/69/EC of the European Parliament and of the Council of 16 November 2000 relating to limit values for benzene and carbon monoxide in ambient air

Kotzias, D., Geiss, O., Tirendi, S. et al. (2009). Exposure to multiple air contaminants in public buildings, schools and kindergartens - the European indoor air monitoring and exposure assessment (AIRMEX) study. Fresenius Environmental Bulletin. 18(5a): 670-681.

HEAL and The European Lung Foundation’s Indoor air quality and the lungs factsheet

Damp and Mould Directory and Brochure The new directory was produced by HEAL based on a grant by the WHO European Centre for Environment and Health. Visit our Damp and Mould page

Written on 8 February 2010.


Resources on this issue:


Members active on this issue:


Find your local respiratory health forecasts


Contact person at HEAL:


Damp and Mould Directory and Brochure


Science Update - A service by the European Lung Foundation


Useful links: