Flowers are blooming, animals are mating, humans are sneezing … Welcome to April, the peak month of tree pollen season in North Carolina.

The N.C. Division of Air Quality reports that pollen levels have spiked in the past week. Each day billions of these tiny particles are released by trees, dispersed by wind or insects and end up settling in every nook and cranny. That fluorescent yellow dust caking your windshield is pine tree pollen, but in fact the culprit of your allergies may be invisible pollen from oak, hickory and other hardwood trees. The worst time for pollen is early morning on dry, windy days; cool, wet periods offer temporary respite.

If you’re suffering from ruthless hay fever, or just general annoyance, you can blame climate change. Harsh winter and sudden springplus record high levels of carbon dioxide in the airnurture conditions for trees that produce pollen.

35 million Number of Americans who suffer from pollen-related allergies

5-10 a.m. Hours when pollen levels are highest

1,756 Grains per cubic meter, pollen count in Raleigh last week

30% Estimated increase in pollen levels by 2020

SOURCES: National Institute of Allergies and Infectious Diseases,, N.C. DENR Division of Air Quality, Live Science, N.C. Botanical Garden

This article appeared in print with the headline “Spring’s tiny troublemaker.”