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, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...
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 skin that 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, cracke ...
es or
itch
An itch (also known as pruritus) is a sensation that causes a strong desire or reflex to scratch. Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both ...
ing), or that are highly poisonous when ingested even though their
pollen
Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...
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
1904–1918: Founding
The organization was ...
and the
U.S. Department of Agriculture
The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and production ...
Urban and Community Forest Service.
More recently, the
California Public Health Department has endorsed the use of this allergy scale in city
landscape planning
Landscape planning is a branch of landscape architecture. According to Erv Zube (1931–2002) landscape planning is defined as an activity concerned with developing landscaping amongst competing land uses while protecting natural processes and ...
to reduce
asthma
Asthma is a common 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 wh ...
.
References
External links
* {{Official website, http://www.allergyfree-gardening.com/opals.html
Allergology
Medical scales