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Sneezing and Wheezing: Ragweed, Ozone, and Global Warming

October 17, 2007

Posted by Gina Solomon in Health and the Environment , Solving Global Warming

Tags:

allergies, asthma, co2, globalwarming, ozone, ragweed

Asthma and allergies are among the most annoying and even disabling common health problems. About 36 million Americans suffer from some kind of allergy, and about 17 million people have asthma. These diseases result in millions of missed school days, missed work days, and hospitalizations... not to mention plain old misery and suffering. As an allergy sufferer, I have personal experience dealing with this from both the doctor's and the patient's perspective. Not fun either way.

So when the science started emerging that ragweed -- that most noxious of allergens for those of us with late-summer symptoms -- will thrive with global warming, I was pretty annoyed. It seems like with global warming, the hits just keep coming. Researchers from Harvard and the U.S. Department of Agriculture tried growing ragweed in greenhouses and exposing the plants to the levels of carbon dioxide that we experienced in pre-industrial times, the levels in the air today, and the levels expected by about 2050, and they found that the nasty weed produced about 130 percent more pollen today and will produce about 300 percent more pollen in the future. Worse still, the warmer temperatures may allow this weed to spread to new areas. You can read one of their studies here.

But it's not just ragweed that's linked to global warming. And it's not just pollen that hurts allergy sufferers. Ozone smog is also sensitive to temperature. That's why the smoggiest days are always the hot days of summer. Despite efforts to control air pollution, global warming is projected to reduce or even eliminate a lot of the efforts to control smog, and it may even make ozone pollution worse.

So here's the kicker: other scientific studies show that ozone and pollen seem to have a synergistic effect, so when people with allergies are exposed to both (instead of just one or the other), they get far more serious reactions.

My team of researchers at NRDC decided to take a look at this issue. We mapped the areas in the U.S. where ragweed has been reported, and we mapped the areas where ozone levels have exceeded the national standards within the past five years. Then we honed-in on the overlap zone. That overlap zone is pretty big, and it encompasses 309 counties where 150 million people live. It includes the Los Angeles basin, the Mississippi River basin, the Great Lakes states, and the entire Atlantic seaboard from Georgia to Maine. These are areas where people are living today with the "double-whammy" of ozone and ragweed pollen.

It's hard to say how much worse things will get in the future, but it's reasonable to be concerned. People with allergies and asthma might want to learn if they live in a zone where there's ragweed or ozone problems, and whether they're sensitive to ragweed. Here's some advice if you want to be prepared for ragweed season. For more information about ozone, and what can be done about it, check out this ALA factsheet.

Fundamentally, what we need is some government action to reduce ozone levels by bringing the National Ambient Air Quality Standard (NAAQS) down to a level that will protect human health, and reducing sources of pollution. At the same time, we need action to stop global warming and reduce carbon dioxide pollution. Can we do it?

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