New Maps Reveal Global Warming's Link to Allergies and Asthma

Increases in Ragweed and Smog Could Produce “Double-Whammy” for Allergy and Asthma Sufferers in Major Cities Throughout the U.S.

NEW YORK (October 17, 2007) – New maps resulting from analysis by the Natural Resources Defense Council (NRDC) find that regions most affected by ragweed and smog substantially overlap with one another — leaving these regions particularly vulnerable to the effects of global warming.  As global warming boosts levels of both ragweed and smog, the risk of asthma and allergic reactions for people living in these overlapping regions will likely increase.
“Our analysis reveals that there is a clear interplay between high levels of smog and ragweed that could lead to intensified reactions for both allergy and asthma sufferers,” said Dr. Kim Knowlton, NRDC’s global warming and health specialist. “People living in some of the most populated regions of this country may be feeling the effects of global warming every allergy season.”
The report, “Sneezing and Wheezing: How Global Warming Could Increase Ragweed Allergies, Air Pollution and Asthma,” finds that 110 million Americans live in areas with both ragweed and smog problems. These areas stretch throughout 308 counties in the United States, including the Los Angeles area, the Great Lakes region, the Eastern seaboard, and a majority of the Mississippi River Valley. Major metropolitan areas where people’s health could be most vulnerable to ragweed and smog include:
  • Atlanta, GA
  • Philadelphia, PA
  • Raleigh, NC
  • Knoxville, TN
  • Harrisburg, PA
  • Grand Rapids, MI
  • Milwaukee, WI
  • Greensboro, NC
  • Scranton, PA
  • Little Rock, AR
  • Los Angeles, CA
  • Chicago, IL
  • Charlotte, NC
Detailed mapping can be found here:
Not only do these cities already rank among the top 15 “Asthma Capitals” of 2007, according to the Asthma and Allergy Foundation of America, but they are also located in the zones most likely to experience ragweed and unhealthy smog levels.   Both ragweed, the pollen of which is a common allergen, and smog, otherwise known as ground-level ozone pollution, have been linked to respiratory problems, including asthma. Studies have shown that when people are exposed to both ragweed and smog, they can suffer more severe reactions than when exposed to just one of these pollutants. 
Global warming may worsen levels of both smog and ragweed, but it will do so in different ways. Smog can intensify when exposed to the rising temperatures caused by global warming. And ragweed has been shown to flourish and produce more pollen through direct exposure to carbon dioxide, global warming’s leading pollutant.
“Global warming – through both its components and by-products – is creating a perfect storm of sneezing and wheezing for allergy and asthma suffers in the U.S.,” said Dr. Gina Solomon, a senior scientist in NRDC’s health program. “This mapping shows us that people throughout the U.S. – in the North, South, East and West – will be very personally affected by global warming, and we need pollution controls throughout the country to help offset this problem.”
Today, about 36 million Americans suffer from some form of seasonal allergy, and it’s estimated that 17 million children and adults in the United States suffer from asthma. Eighty percent of children and 50 percent of adults with asthma also have some type of allergy, and allergies are among the factors that can trigger asthma attacks.
There are both large-scale and individual actions that can be taken to reduce the effects of this possible rise in ragweed and smog on asthma and allergies. Government agencies can protect communities by reducing the sources of global warming pollution and ozone smog. Governments can create better resources for citizens in need of information about pollen and pollution levels in their area, such as implementing more ozone monitoring stations and ragweed tracking systems. Individuals can reduce their own exposure to ragweed and smog by checking news outlets for daily pollen and smog levels, and reducing outdoor activities when these levels are high.