April 04, 2011

The Benefits of Stronger air pollution standards for Cars and Trucks

More stringent emissions standards for motor vehicles would affect regions differently. Climate impacts are shown in terms of radiative forcing (top row), a measure of the change in the Earth's energy balance. Positive forcing accelerates global warming, whereas negative forcing slows it. Health benefits are shown as avoided premature deaths (2nd row). Agricultural benefits are shown as avoided yield loss in percent (3rd row), and the avoided damages due to the health and crop yield changes are shown in US dollars (bottom row). Credit: NASA/Drew Shindell

A new analysis, published this week and conducted by a team of scientists led by Drew Shindell of NASA's Goddard Institute for Space Studies (GISS) in New York City, shows stricter vehicle emission standards would yield major health, agricultural, and climate benefits.

Shindell and colleagues used a comprehensive computer model and climate simulator — one of the first capable of accounting for the role of short-lived particles expelled in vehicle fumes called aerosols — that shows vehicle fumes exact an enormous toll in all countries and especially in the developing world.

NOTE: the calculated savings in reduced deaths is only from stronger air pollution controls for cars and trucks and does not include better air pollution controls on coal plants and other industrial and power generation sources.

The aggressive scenario assumes, for example, that China, India, and Brazil adopt "Euro 6" standards by 2015, a regime that would reduce emissions of particulate matter by about 85 percent, nitrogen oxides by about 65 percent, and carbon monoxide by about 70 percent for passenger vehicles. The aggressive scenario assumes major emissions reductions in Latin America, Africa, and the Middle East, the regions with the laxest emissions standards. Emissions rules in North America are slightly more stringent than European standards already, so in North America the baseline and aggressive scenarios were identical.

Human Toll, Plant Toll

Particulate matter from vehicle fumes can slip past the body's defenses — hair-like structures in the respiratory tract and hairs in our noses — and penetrate deep into the lungs. There, it can spark a range of diseases such as asthma, cardiovascular disease, and bronchitis.

Ozone, the product of reactions between nitrogen oxides, carbon monoxide or hydrocarbons, and sunlight, can harm both people and plants. In humans, it inflames the lining of air passages making breathing more difficult and can scar lungs after long periods of exposure. In crops, it damages cell membranes, slowing photosynthesis and reducing yields.

"The adoption of aggressive standards by 2015 would set the world on a course to prevent the deaths of 200,000 people, save 13 million tons of cereal grains from ozone damage, and save $1.5 trillion in health damages each year after 2030," Shindell said.

After five years, that would amount to saving a million lives, more than 50 million tons of food, and $7.5 trillion in human health damages. Health damages are based on an accounting technique economists use to weigh the benefits of life-saving regulations called the "value of a statistical life."

For comparison, the United Nations estimated that the earthquake and tsunami that struck the northeast coast of Honshu had caused about 27,600 deaths and produced between $185 and $308 billion in damages at the end of March. Hurricane Katrina killed 1,836 people and produced about $81 billion in damages.

The analysis also breaks down potential health benefits by region and finds benefits varied widely. Overall, the modeling found that stricter standards would prevent the most deaths in China, India, and North Africa, regions where unfiltered soot-producing diesel engines remain ubiquitous.

While reductions in particulate matter tend to produce local health benefits, the scientists found health and agricultural benefits from reduced ozone disperse more widely. That means for some countries — India, for example — changes in emissions from neighboring countries could have as much impact as local emission changes.

"There is no one-size-fits-all approach to emissions standards. Different countries are going to need different approaches," Shindell said.

Nature Climate Change - Climate, health, agricultural and economic impacts of tighter vehicle-emission standards

Non-CO2 air pollutants from motor vehicles have traditionally been controlled to protect air quality and health, but also affect climate. We use global composition–climate modelling to examine the integrated impacts of adopting stringent European on-road vehicle-emission standards for these pollutants in 2015 in many developing countries. Relative to no extra controls, the tight standards lead to annual benefits in 2030 and beyond of 120,000–280,000 avoided premature air pollution-related deaths, 6.1–19.7 million metric tons of avoided ozone-related yield losses of major food crops, $US0.6–2.4 trillion avoided health damage and $US1.1–4.3 billion avoided agricultural damage, and mitigation of 0.20 (+0.14/−0.17)  °C of Northern Hemisphere extratropical warming during 2040–2070. Tighter vehicle-emission standards are thus extremely likely to mitigate short-term climate change in most cases, in addition to providing large improvements in human health and food security. These standards will not reduce CO2 emissions, however, which is required to mitigate long-term climate change.

32 pages of supplemental information

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