Airborne allergens are environmental factors playing an important role in the development, persistence, and possibly severity of asthma. In Singapore, more than 80% of children with asthma above the age of 4 years are sensitized to dust mite allergens 1. Studies have shown that house-dust mite and cockroach exposure are linked to the prevalence of sensitization and subsequent development of asthma 2,3. In addition, allergen exposure can promote the persistence of airway inflammation and likelihood of an exacerbation. Substantially reducing such exposure may significantly reduce inflammation, symptoms, and need for medication.