The OsmohalerTM is a registered device in Australia. It is used to deliver a dry powder a commercial preparation of mannitol registered as AridolTM to test if a person has irritable airways such as active asthma.

The overseas regulatory authorities need to know that people of all ages can achieve an adequate inspiratory flow through this device during a controlled deep inspiration. Adequate flow is generally regarded as greater than 30 litres per minute in children and 60 litres per minute in adults. The OsmohalerTM is a device with low resistance and is already in use in Australia to deliver mannitol. However there is a need to document inspiratory flows through the device during a controlled deep inspiration. The protocol requires subjects to perform a controlled deep inspiration from the device on three or five occasions. No substance will be inhaled.

Inclusion Criteria:

• has asthma or is healthy
• aged 6 to 69 years inclusive
• FEV1 >/= 70% predicted

Exclusion Criteria:

• has condition contraindicating performance of spirometrt