National Allergy Report

Birches in the genus Betula are among the most recognizable spring-pollen trees in North America. For allergy sufferers, they matter because birch pollen is lightweight, readily airborne, and strongly associated with classic spring hay fever. In the United States, the biggest wild-birch exposure zones are the Northeast, Great Lakes, Upper Midwest, Alaska, and mountain West, but the birch story does not stop there. River birch extends the genus well into the Mid-Atlantic, Southeast, lower Midwest, and parts of south-central states, so birch-related exposure can appear outside the colder northern forest belt many patients expect.^1-3

Cincinnati also remained very high for grass pollen, while South Central readings held high around Oklahoma City, Tulsa, and Waco and Puerto Rico remained active for both grass and trees. Tree pollen has become more localized than earlier in spring; weeds were mostly quiet, but mold rose in Chicago, St. Louis, and San Antonio.

Grass pollen season started in earnest last week across a broad swath of the U.S., especially in the South and West, while the Midwest and Northeast still suffer from high tree pollen levels.

Spring tree pollen is now a national story: elevated readings stretched from Wisconsin and Nebraska to New Jersey, Kentucky, South Carolina, Alaska, Washington, and Puerto Rico. Grass became a big new irritant, with more high readings in the South Central, Southeast, Northeast, and parts of the West, while weeds and mold were mostly limited exceptions

Tree pollen is still the biggest allergy problem for many readers, especially in the Midwest, Puerto Rico, and parts of the South Central region. The Midwest remains the broadest mainland trouble spot: five of seven current stations reached High or Very High tree pollen, with La Crosse still in the top band and Chicago, Greenfield, Madison, and Omaha also elevated.