Question 1: “Does rain really help ‘wash out’ pollen from of the air?”
It is true that rain helps clean the air of pollen, dust and any other particles small enough to stay airborne… but it also depends on the size of raindrops. All raindrops develop a small electrical charge when falling through the air that attracts particles (like pollen spores) — but smaller raindrops are better at cleaning the air due to the combination of this electrical charge and the larger surface area-to-volume ratio. Light, steady rain helps filter the air more effectively than large drops coming out of a heavy rain shower.
Question 2: “We often see a spike in mold count after rain events… why is that?”
Mold thrives in damp and humid conditions. High humidity and wet conditions after a rain event will more-often-than-not be followed by an increase in mold levels.
Question 3: “What about temperatures? Has our unusually warm weather helped or hurt us?“
It all depends on the timing of those warm temperatures. This year (2020), we did not see a January freeze in Austin meaning trees and other plants have had the chance to pollinate earlier this winter, getting a head start on spring & extending the pollen season. Both warm temperatures and longer days (more sunlight) trigger pollination.
Question 4: “Does humidity affect pollen counts?”
The higher the humidity, the more a pollen grain gets damp and heavy with moisture. This helps keep the pollen from becoming airborne (lower pollen count). The exception? Mold. (See question 2 above).
Question 5: “What happens to pollen counts on a windy day?”
Strong winds allow for greater dispersion of pollen spores/grains. Some researchers have been able to source a particular pollen that originated +1000 miles away!
Question 5: “Is climate change impacting pollen season?”
Yes. Climate change is extending the pollen season (warmer temps in the winter = earlier pollination). It’s also allowing plants to now find a suitable environment in areas previously not conducive for growing.
For KXAN’s daily pollen counts, click here.