Prevention: Your Best Defense Against Pollen
Brought to you by National Institute of Environmental Health Sciences
General Pollen Preventive Strategies
- Avoid the outdoors between 5–10 AM and on dry, hot and windy days when pollen counts are highest. Save outside activities for late afternoon or after a heavy rain, when pollen levels are lower.
- Keep windows closed to lower pollen exposure. To keep cool, use air conditioners and avoid window and attic fans.
- Be aware that pollen can also be transported indoors on people and pets.
- Dry your clothes in an automatic dryer rather than hanging them outside. Otherwise, pollen can collect on clothing and be carried indoors.
Ragweed Pollen
Ragweed and other weeds such as curly dock, lambs quarters, pigweed, plantain, sheep sorrel and sagebrush are some of the most prolific producers of pollen allergens. Although the ragweed pollen season runs from August to November, ragweed pollen levels usually peak in mid-September in many areas in the country.
Grass Pollen
Grass pollen is regional as well as seasonal. In addition, grass pollen levels can be affected by temperature, time of day and rain. Of the 1,200 species of grass that grow in North America, only a small percentage of these cause allergies. The most common grasses that can cause allergies are:
- Bermuda grass
- Johnson grass
- Kentucky bluegrass
- Orchard grass
- Sweet vernal grass
- Timothy grass
Specific Preventive Strategies
- If you have a grass lawn, have someone else do the mowing — if you must mow the lawn yourself, wear a mask
- Keep grass cut short
- Choose ground covers that don't produce much pollen, such as Irish moss, bunch and dichondra
Tree Pollen
Trees are the earliest pollen producers, releasing their pollen as early as January in southern states and as late as May or June in northern states. Trees can aggravate your allergy whether or not they’re on your property, since trees release large amounts of pollen that can be distributed miles away from the original source. Of the 50,000 different kinds of trees, less than 100 have been shown to cause allergies. Most allergies are specific to one type of tree such as:
- Catalpa
- Elm
- Hickory
- Olive
- Pecan
- Sycamore
- Walnut
Specific Preventive Strategies
- If you buy trees for your yard, look for species that don’t aggravate allergies such as crape myrtle, dogwood, fig, fir, palm, pear, plum, redbud and redwood trees
- You can also plant the female cultivars of ash, box elder, cottonwood, maple, palm, poplar or willow trees, which don’t cause allergies
To learn more, visit www.niehs.nih.gov.
