No, you aren't imagining it — your allergies really are getting worse. And you can thank air pollution for the extra sniffles and sneezes. 

Health experts have long suspected that air pollution might play a role in the magnitude of allergy symptoms, but they never understood why or how that role occurred until now.

New research, presented at the annual meeting of the American Chemical Society, uncovered how common pollutants interact with allergens at the chemical level, amplifying the effect — and the symptoms — of allergies. According to the study, two common pollutants including ozone, a component of smog, and nitrogen dioxide, which is created by diesel exhaust, alter the chemical makeup of airborne allergens, making them that much more potent. 

Using computer simulations and laboratory tests, the research team from the Max Planck Institute for Chemistry in Germany examined the effects of ozone and nitrogen dioxide on Bet v 1, a major birch pollen allergen. Their research showed that ozone oxidizes an amino acid called tyrosine that increases production of Bet v 1 proteins. These altered and more potent allergens then react with nitrogen dioxide, which increases their binding capabilities and thus increases the immune system's response. The end result? More sniffling, sneezing and runny noses, especially on days that are hot, humid and smoggy.

And the effects don't end there.

The researchers noted that the two pollutants also play a major role in climate change, a situation that is extending allergy season by increasing the number of days we are exposed to pollen

“Humans are not just affecting but shaping the environment ... it’s actually unreasonable to assume that it would not affect humans with our highly delicate immune system,” said Ulrich Poschl, the lead researcher for the study. “That’s the background motivation for these kinds of studies.”

Bottom line: Better stock up on tissues. 

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Are your allergies getting worse? Blame air pollution
New research uncovers how common pollutants alter allergens to make them more potent.