Diesel particulate pollution down 50%, CARB says

| May 30, 2012

The California Air Resources Board last week heard the research findings from six experts describing the potent and near-term contribution to climate change posed by black carbon, methane and hydrofluorocarbons. The scientists also explained that reducing emissions of these short-lived global warming compounds would be a highly effective strategy to mitigate the impacts of climate change, especially in Arctic regions.

“We have known for years that black carbon hurts our lungs and shortens people’s lives,” says Mary Nichols, CARB chairman. “The new science tells us that by controlling these compounds, we can also make a significant difference in averting some of the worst effects of global climate change.”

Short-lived climate pollutants include black carbon (the black soot portion of health-damaging fine particle pollution), methane (the primary constituent of natural gas and also emitted by livestock) and hydrofluorocarbons (industrial chemicals used in refrigeration and air conditioning).

Unlike carbon dioxide which stays in the atmosphere for about a hundred years, these three have a relatively short atmospheric lifetime ranging from a few days to a few decades. Even so, they tend to have strong and immediate global warming influences. Actions to reduce emissions of these short-lived climate pollutants will produce a relatively rapid reduction in their contribution to climate change.

California has been addressing fine particle pollution from diesel engines over the past 10 years, and findings presented last week indicated a 50 percent reduction of these compounds in ambient air over the past 20 years. “It is encouraging to see that CARB’s diesel regulations, while designed to improve public health, are also addressing climate change,” says Nichols.

California also has measures in place under AB 32 to reduce emissions from large commercial refrigeration units, an approach that reduces emissions of hydrofluorocarbons into the atmosphere. In addition, the findings presented last week also support ongoing efforts by CARB to address methane emissions in the agricultural sector as part of a comprehensive energy strategy.