1. Absorption: how does a chemical substance enter the body?

1.1 The lungs, the main route by which chemicals enter the body

The lungs are the main route of entry in the following cases:

• if your substance is a gas;

• if it's a powdery solid;

• if it's a liquid with a very high vapor pressure and/or a very low boiling temperature;

• whether the liquid is in droplet or aerosol form.

The lungs have a very large surface area for exchange with ambient air (alveolar surface area of around 100 to 150 m ² ).

The volume of air inspired is very important in determining the amount of product that enters the...