Inclusion Criteria:

- Asthmatic and control children, aged 5 to 16 years

- Children with doctor-diagnosed asthma, known at the department of Paediatric
Pulmonology, University Hospital Maastricht

Exclusion Criteria:

- Presence of a disease that might interfere with the results of this study (e.g.
recent upper airway infection, heart disease, anatomic abnormalities of the airways
and other chronic inflammatory diseases such as Crohns disease and rheumatoid
arthritis)

- Mental retardation

- Inability to perform the EBC procedure properly

- Active smoking

- The use of one of the following medication: Papaverin, Sodium nitroprusside, ACE
inhibitors, Oxymetazoline, L-arginine, or NOS inhibitors