Carbon dioxide emissions are bad for human health, study finds

Posted by Laura Grant on January 4, 2008
Posted in Green News

For each 1 degree Celsius increase in temperature caused by carbon dioxide emissions, the resulting air pollution could lead to more than 20,000 deaths a year worldwide and many more cases of respiratory illness and asthma, a Stanford University study has found.

According Mark Jacobson, a professor of civil and environmental engineering at Stanford, the study is the first specifically to isolate carbon dioxide’s effect from that of other global-warming agents. It is also the first to find quantitatively that “chemical and meteorological changes due to carbon dioxide itself increase mortality due to increased ozone, particles and carcinogens in the air”.

Ozone in the upper atmosphere helps to block harmful sun’s rays, but near the Earth’s surface it is a pollutant. Many studies have associated increased ozone with higher mortality, the university says. Ozone causes and worsens respiratory and cardiovascular illnesses, emphysema and asthma, and many published studies have associated increased ozone with higher mortality.

Particles are responsible for cardiovascular and respiratory illness and asthma.

“[Ozone] is a very corrosive gas; it erodes rubber and statues,” Jacobson said. “It cracks tyres. So you can imagine what it does to your lungs in high enough concentrations.”

Using a complex computer model to determine the amounts of ozone and airborne particles that result from temperature increases caused by carbon dioxide emissions, Jacobson found that the effects are most significant where the pollution is already severe, such as in cities.

He found that higher temperatures due to carbon dioxide increased the chemical rate of ozone production in urban areas; plus increased water vapour due to the higher temperatures boosted chemical ozone production even more in urban areas.

Also, he adds, where there is an increase in water vapour, “That added moisture allows other gases to dissolve in the particles – certain acid gases, like nitric acid, sulfuric acid and hydrochloric acid.” This increases the toxicity of the particles, which are already a harmful component of air pollution.

“Ultimately, you inhale a greater abundance of deleterious chemicals due to carbon dioxide and the climate change associated with it, and the link appears quite solid,” said Jacobson.

“The logical next step is to reduce carbon dioxide: that would reduce its warming effect and improve the health of people in the US and around the world who are currently suffering from air pollution health problems associated with it.”

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