This study seeks to document differences in nasal irritant sensitivity within the population. The investigators are interested in knowing whether age, gender, and allergy status (nasal allergies) predict nasal irritant sensitivity. This is important in understanding symptom reporting patterns in air pollution situations (particularly in so-called "problem buildings"), as well as in understanding the reflex mechanism of a response of the nose to irritants (e.g., nasal congestion).

Inclusion Criteria:

• Non-smokers
• 18-69 years of age
• With or without allergic rhinitis (hay fever)
• In good general health and with no prior history of asthma