This trial in healthy subjects will assess PUR118's effect on attenuating ozone induced airway inflammation. This trial will establish the tolerability of PUR118 in healthy normal volunteers.

Inclusion Criteria:

• Healthy males or non pregnant, non lactating healthy females age 18-50 years;
• Must be able to produce acceptable sputum sample by induction;
• Must respond to ozone inhalation with a > 10% increase in the absolute percentage of sputum neutrophils and the total neutrophils (neutrophils/gram sputum) must increase by at least 50% from the sputum neutrophil count at screening;
• Volunteer is a non-smoker or ex-smoker of at least 12 months' duration prior to screening with a history of less than 1 pack per year.

Exclusion Criteria:

• Volunteers receiving chronic medication other than oral contraceptives;
• Screening forced expiratory volume FEV1 is < 80% of the predicted value for their age, gender, height and race and/or their FEV1/FVC ration is below 70%;
• Volunteers with significant occupational exposure to respiratory irritants or toxins
• Upper respiratory tract infection within 30 days of the first study day, or lower respiratory tract infection within the last 3 months;
• Volunteers taking any medication that may affect the respiratory tract within 30 days of the first study day;
• Volunteers with a history of asthma