By Stephanie Stahl

PHILADELPHIA (CBS) –What’s not to love about a beautiful sunny day?

“I’d be all stuffed up. My eyes would be all red and watery and puffy,” says Scott Chin, an allergy sufferer.

And if you’re among the millions of people like Scott who suffer with seasonal allergies, there are plenty of reasons to avoid going outside.

“Miserable this time of year,” Scott adds.

“I am seeing more people coming in with newly acquired allergic disease,” said Dr. John Costa, an allergist.

He says allergies are hitting harder and lasting longer.

“It’s not uncommon for patients to say, ‘Wow, this year is the worst I’ve had ever,’” explains Dr. Costa.

Now, researchers are looking into a possible link between global warming and the increase in allergies.

Dr. Christine Rogers says rising temperatures have plants flowering earlier, lengthening the allergy season by about two or three weeks. And she says warmer temperatures increase carbon dioxide in the atmosphere, which also has a direct effect on plants.

“For our studies for ragweed, we’re finding with double the amount of co2, we’re seeing a 50% increase in the amount of pollen that’s produced,” says Dr. Rogers.

Experts say the air we breathe already has the highest levels of carbon dioxide ever recorded in human history, and that the levels are predicted to climb even higher.

“We can reasonably anticipate that in the future, there is going to be a lot more exposure to pollen, and that will precipitate more symptoms,” explains Dr. Rogers.

Scott finally resorted to allergy shots.

“I just feel like normal. And I can enjoy being outside,” he says.

Right now in the Philadelphia region, mold levels are extreme. Ragweed is moderate. Doctors say allergy shots are just one option; there are many other kinds of allergy medications and sprays.

For more information on seasonal allergies, visit:

For an allergy drug guide, visit:

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