Your offi ce greenery needs to tolerate interior lighting conditions, haphazard watering, and low humidity. It also needs to be people friendly. Allergens are a real concern to many people and you need to respect that when shrubbery shopping. To help you choose low allergen plants for the office, turn to the Ogren Plant Allergy Scale (OPALS), it measures the allergy potential of all landscape plants, with an emphasis on direct inhalants, specially those that may provoke asthma. OPALS is the system used by the American Lung association and progressive Canadian cities, including Edmonton and Toronto, that are striving to create a better air quality experience.