Sen. Scott Brown is wrong: Carbon pollution is connected to asthma and sick children

Kim Knowlton, in an NRDC Action Fund repost

Recently, Senator Scott Brown denied that carbon emissions and climate change are connected to asthma and sick children, saying “Nothing could be further from the truth.”

In fact, the Senator couldn’t be further off-base.

  • Climate change will lead to higher concentrations of ground-level ozone (smog) in many areas of the country; smog is a pollutant known to exacerbate asthma and respiratory diseases and boost hospital admissions for respiratory illnesses.
  • Rising temperatures are associated with lengthening pollen seasons, which could worsen allergy symptoms and have serious health consequences for asthma sufferers. The burden of these climate change impacts will be most strongly felt by children.

While there are more scientific studies than can be summarized here, the key studies below support the conclusion that carbon emissions and climate change are connected to asthma.

Here’s a quick scan:

1. Climate change is expected to lead to higher concentrations of ground-level ozone (smog):

A warmer climate is projected to increase emissions of the chemicals that form ozone smog, , speed up ozone-forming chemical reactions in the air, and increase the frequency and duration of stagnant air masses that allow pollution to accumulate, worsening health symptoms. Increased temperatures due to human-induced carbon pollution increase ozone smog more in areas with already elevated concentrations, meaning that climate change tends to worsen ozone pollution most in already-polluted areas.


Global Climate Change Impacts in the United States. Karl TR, Melillo JM, Peterson TC (eds.). Cambridge University Press (2009).2. Ozone triggers and worsens asthma symptoms:

Breathing ozone triggers chest pain, coughing, throat irritation, and congestion; and can worsen bronchitis, emphysema, and asthma. Exposure to ground-level ozone smog can also reduce lung function and inflame the linings of the lungs; repeated exposure may permanently scar lung tissue. The 2010 Interagency Working Group on Climate Change & Health (IWGCCH)/NIEHS report, “A Human Health Perspective on Climate Change”

It has been firmly established that breathing ozone causes inflammation in the deep lung. Epidemiologic studies of people living in polluted areas show ozone increases the risk of asthma-related hospital visits and premature mortality. Vulnerability to ozone effects on the lungs is greater for people who spend time outdoors when ozone levels are high, especially those who engage in physical exertion, which results in a higher cumulative dose to the lungs. Children, outdoor laborers, and athletes all are at greater risk than people who spend more time indoors and are less active. Asthmatics are also a vulnerable subgroup.

Kinney PL. 2008. Climate change, air quality, and human health. Am J Prev Med 35:459–467.

3. Rising temperatures and carbon pollution increase pollen production, and are likely to increase allergies, worsening asthma:


Climate change-related increased burden of disease, specifically from allergy and asthma, is anticipated because of changes in the distribution, quantity, and quality of pollen, and lengthening of the pollen season. Asthma and allergic disease will also likely be worsened because of interaction between heavier pollen loads and increasing air pollution from natural and man-made sources. People with allergy and asthma may expect worsening disease, more days with symptoms, and reduced quality of life as a result of these environmental changes.

KM Shea, RT Truckner, RW Weber, DB Peden. Climate change and allergic disease. Clinical Reviews in Allergy and Immunology 2008; 122(3):443–453.

Rising carbon pollution, or carbon dioxide (CO2), increases the growth and pollen production of plants like ragweed, and the pollen produced may be more allergenic. Along with these health-harming aeroallergens, other effects of burning fossil fuels can pose a “double whammy” to health; for example fossil fuel-produced diesel particles can help deliver allergens deeply into lung airways and irritate immune cells. Climate change effects on plant biology, and subsequent effects on aeroallergens and public health may help explain the quadrupling of asthma in the United States since 1980.

Ziska L, et al. Rising CO2, Climate Change, and Public Health: Exploring the Links to Plant Biology. Environ Health Perspect 2009; 117(2): 155–158.

4. Children are especially at risk:

Children are particularly vulnerable to the effects of global warming. Global warming compounds the toxicity of fossil-fuel pollutants such as ozone, an important trigger of childhood asthma. Ozone formation from volatile organic chemicals and nitrogen dioxide is accelerated at higher temperatures. Another consequence of a warmer climate is increased plant growth and pollen production, and thus higher levels of natural allergens leading to more allergy and asthma in children.


Perera, F. Children Are Likely to Suffer Most from Our Fossil Fuel Addiction. Environmental Health Perspect 2008; 116 (8):987–990.

Earlier this month, the Centers for Disease Control & Prevention (CDC) reported that asthma is rising in the U.S., with 25 million people now afflicted, and the numbers are increasing every year. The risk of asthma is highest among children. The greatest increase between 2001 and 2009 was seen among African-American children — an almost 50% increase in asthma rates. One in six (17%) of non-Hispanic black children in 2009 had asthma.

The connections between carbon pollution, climate change, air quality, and health have never been more important, especially for our children.

— Kim Knowlton

JR: As CP reported last year, Stanford researcher Mark Jacobson, found carbon dioxide pollution not only causes global warming but also forms “domes” that trap other pollutants in urban areas:

Jacobson found that domes of increased carbon dioxide concentrations — discovered to form above cities more than a decade ago — cause local temperature increases that in turn increase the amounts of local air pollutants, raising concentrations of health-damaging ground-level ozone as well as particles in urban air.

Here are some comments from Jacobson in a 2011 email interview:

Global warming increases air pollution where the air pollution is already high but has less effect on air pollution where the air pollution is low.

Warming increases water vapor, and both water vapor and higher temperatures increase ozone where the ozone is already high but have less effect where the ozone is low.

Carbon dioxide domes over cities increase temperatures over the cities above and beyond the heat island effect, and these higher temperatures increase water vapor, and both higher water vapor and higher temperatures increase the rates of chemical air pollution production over cities relative to rural areas.

The results suggest a causal nature of increased air pollution mortality due to increased carbon dioxide where the air pollution is already high. Thus, controlling CO2 emissions at the local level will reduce air pollution and the resulting air pollution mortality.