We are exposed to many compounds, including nanomaterials, through the air we breathe. On average, we inhale more than 300 million litres of air in our lifetime – the volume of 120 Olympic swimming pools.

We inhale nanoparticles in many different situations, for example, when using cosmetics or spray products in our homes, or from exhaust fumes from vehicles and other sources.

Some airborne nanoparticles are harmless and will not damage your lungs. Others, however, may cause health problems, allergic reactions or even tumours. One example is titanium dioxide which is found in sunscreens and is suspected of causing cancer if inhaled. This is why any product containing this substance above a certain limit has to be labelled to warn people and prevent them from breathing it in.

Different forms of the same nanomaterial can even have different effects. For example, breathing in some forms of carbon nanotubes may cause fibrosis and cancer in the lungs, while other forms do not.

To understand if a nanomaterial can cause acute or chronic effects, scientists carry out both short and long-term studies. The results can help to manage the possible risks of nanomaterials. For example, they can show where protective equipment may be needed to avoid breathing in a harmful nanomaterial.