News
Grass Pollen Stays Elevated Across the West, Midwest, and Southern Plains as Puerto Rico Picks Up
Grass pollen remains the main outdoor burden for the broadest set of allergy sufferers. The strongest clusters were in the West, Midwest, and South Central region: Oregon, Washington, Montana, Wisconsin, Minnesota, Oklahoma, and parts of Texas all had high grass readings. Seattle slipped from last week's peak but stayed elevated, while La Crosse and Oklahoma City moved up into the high range and Austin, Greenfield, Eugene, Missoula, Portland, and Waco South held there.
Puerto Rico became more active. Caguas reached high levels for both grass and tree pollen, and San Juan also moved up for trees. On the mainland, tree pollen now looks late-season and mostly below high levels: Western stations including Anchorage South and Missoula stepped down, and Northeast stations such as Lebanon NH, New York City, and Olean were low after being more active last week.
Mold remained a local, not national, problem. Chicago and St. Louis stayed high for mold in the Midwest, and San Antonio East stayed high in South Central. Mold pressure eased elsewhere in that region, with Austin and Oklahoma City dropping below high levels. Weeds stayed mostly quiet, aside from Austin, Minnesota, where sheep sorrel and dock pushed weed readings into high territory; other weed movement was mostly low to moderate.
High Allergy Burden Locations
| Location | Allergen | Level | Drivers |
|---|---|---|---|
| Austin (Georgetown), TX | Grass | High | Grass Family, all types |
| Austin, MN | Grass | High | Grass Family, all types |
| Austin, MN | Weed | High | Sheep Sorrel, Dock |
| Caguas (Centro), PR | Grass | High | Other identified grass pollen |
| Caguas (Centro), PR | Tree | High | Other identified tree pollen |
| Chicago (Melrose Park), IL | Mold | High | Ascospores |
| Eugene, OR | Grass | High | Grass Family, all types |
| Greenfield, WI | Grass | High | Grass Family, all types |
| La Crosse (Onalaska), WI | Grass | High | Grass Family, all types |
| Missoula, MT | Grass | High | Grass Family, all types |
| Oklahoma City, OK | Grass | High | Grass Family, all types |
| Portland, OR | Grass | High | Grass Family, all types |
| San Antonio (East), TX | Mold | High | Other identified fungi |
| San Juan, PR | Tree | High | Other identified tree pollen |
| Seattle, WA | Grass | High | Grass Family, all types |
| St. Louis (Berkeley), MO | Mold | High | Ascospores |
| Waco (Woodway South), TX | Grass | High | Grass Family, all types |
Pollen Drivers
Grass readings were mostly carried by the broad grass-family category. That was the driver behind the high grass readings in the mainland locations in Oregon, Washington, Montana, Wisconsin, Minnesota, Oklahoma, and Texas. Caguas's high grass reading was reported as other identified grass pollen rather than a named grass species, so the Puerto Rico grass story is best treated at the category level.
Puerto Rico's tree pollen was also reported through a broad other-tree category at Caguas and San Juan. High tree readings were absent from the mainland stations, which fits the late-season pattern: earlier Western and Northeastern tree pockets are now mostly low or moderate.
Mold's high readings were split between ascospores in Chicago and St. Louis and other identified fungi at San Antonio East. The only high weed reading came from sheep sorrel and dock in Austin, Minnesota.
Weather Context
Much of the central and eastern U.S. turned warmer and less rainy than last week. That coincided with grass staying active or moving higher in parts of the Midwest and South Central region, while the Southeast stayed below high levels across grass, trees, weeds, and mold.
The West was slightly cooler and drier, but grass still held high at Eugene, Missoula, Portland, and Seattle. Tree pollen there moved lower at several stations, including Anchorage South and Missoula, making grass the clearer Western burden.
Puerto Rico's weather changed little, while both available tree stations moved higher and Caguas added a high grass reading. That makes the island pattern more of a pollen-category pickup than an obvious weather shift.
Comments