The Ogren Plant Allergy Scale (OPALS) is an allergy rating system for plants that measures the potential of a plant to cause

allergic reaction Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...

s in humans.

Scale system

The OPALS allergy scale was first published in ''Allergy-Free Gardening'', by Thomas Leo Ogren, in 2000. It covers over 3,000 common trees, shrubs, flowers, and grasses. The allergy scale was updated and extended in 2015 in ''The Allergy-Fighting Garden''. The Ogren Plant Allergy Scale takes into account pollen allergies, contact allergies, and odor allergies, with higher weighting given to pollen allergies that are caused by inhaling pollen into the lungs. Additionally, plants that cause contact allergies (such as

rash A rash is a change of the human skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, c ...

es or

itch Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

ing), or that are highly poisonous when ingested even though their pollen does not cause respiratory allergies, are never given low ratings. Low allergy ratings are considered to be 1 through 3 on the allergy scale. Mid-range ratings are 4 through 6, and high ratings are 7 through 10. Plants with ratings of 9 or 10 have an extremely high potential to cause allergic reactions.

Application

* Canada: The OPALS allergy scale was used in the Canadian Urban Allergy Audit, which was conducted in 2012. * United Kingdom: OPALS allergy scale labels for plants sold at nurseries have recently become available for use within the United Kingdom. * United States: OPALS has been adopted for use by the

American Lung Association The American Lung Association is a voluntary health organization whose mission is to save lives by improving lung health and preventing lung disease through education, advocacy and research. History The organization was founded in 1904 to figh ...

and the

U.S. Department of Agriculture The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of comme ...

Urban and Community Forest Service. More recently, the California Public Health Department has endorsed the use of this allergy scale in city landscape planning to reduce

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...

References

External links

* {{Official website, http://www.allergyfree-gardening.com/opals.html Allergology Medical scales