The lush forests of the Northwest make this a destination spot of choice for people who love hiking and outdoor travel. Fortunately, the region’s most abundant trees — pines and other cone-bearing varieties — have relatively large pollen (it’s hard for our mucous membranes to absorb so it’s not likely to be a problem). And the pollen is so heavy it rarely becomes airborne. Between the less-allergenic conifer pollen and the relatively few allergenic grasses, the Northwest is fairly comfortable for people with pollen allergies most of the year.

Spring

The regular rainfall and moderate temperatures of this region provide a perfect environment for trees. Even though conifers are the prevalent species, the more allergenic oak and cedar trees are also present. They release their pollens from late winter through May. Molds can be a significant problem in this moist region, both indoors and out. Buildings here often have the damp closets and basements molds love, and the rich forest humus provides an ideal setting for mold growth.

Summer

The Northwestern region is geographically diverse, so vegetation tends to be specific to small microenvironments within the larger region. Generally, allergenic grasses pollinate in series beginning in May, and continuing all summer long. While ragweed and sage are found all over the Northwest and bordering states, regional allergenic pollens include Russian thistle (Montana), dock and plantain (Oregon and Washington), salt bush (Idaho), chenopod (Northern California), and many more. Your best bet for avoiding pollen in this region is consulting an area-specific pollen count and planning your trip accordingly. Moderate to warm temperatures and plenty of rain in coastal zones encourage mold growth. Inland areas are drier and warmer. Motionless summer air inland from the breezier coast can lock in a blanket of air pollution over urban areas. Ozone levels can reach such proportions that outdoor activity is discouraged by public health agencies. If airborne chemicals are a problem for you, stick to less-populated rural areas.

Fall

Northwestern Indian summers bring comfortable, warm temperatures and drier air. With few native plants pollinating and mold growth at a minimum, few airborne allergens and irritants will be present to plague the allergic traveler. Dust mites also become relatively scarce, now that humidity is down. Stagnant airflow can continue to blanket urban areas with air pollution, but the ozone and airborne chemical levels are not usually enough to warrant the health advisories common during summer months.

Winter

Heavy storm activity in the Northwest cleanses the air of allergens and irritants for most of the season, but tree pollen season starts in Northern California as early as February. As far as the trees are concerned, late winter in parts of California and Oregon is already early spring. Oak, maple, and acacia all start pollinating now. Between storms, however, smoke from the wood-burning stoves common to this region of the country can linger, irritating those sensitive to smoke and airborne chemicals. Mold activity picks up with this season’s increase in humidity, and dust mites start waking up and reproducing. Winter snowfall at higher altitudes makes for great skiing and winter sports, but the winter-budding vine maple can irritate the pollen-allergic in these same mountain areas.

This entry was posted on Wednesday, August 22nd, 2007 at 8:08 am and is filed under Seasonal & Travel. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.