This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

ST. LOUIS – The spring winds are stirring up the allergens. They affect us all differently.

While spring normally has the highest allergen numbers, elevated values can persist until the start of winter, with weather-induced spikes in between. Collectively, pollen looks like a green haze over the city as seen from Bommarito Automotive Group SkyFOX on a recent high-pollen day.

Sampling and measuring the allergens are difficult work.

Wayne Wilhelm, a lab supervisor with the St. Louis County Department of Public Health, says a certified lab technician stains the completed slide and then counts the allergens methodically according to type: tree, grass, and weeds. The magnification is then increased to count the mold spores. The process is very time-consuming on high pollen days. The allergen counts are shared on the National Allergy Bureau network, recorded on the STL DOPH Allergy line, and shared on its website.

FOX 2 and KPLR 11 meteorologists receive the number electronically and broadcast them daily during weathercasts.