A Stanford University study shows that carbon dioxide is a local problem that hurts city dwellers’ health more than rural resident’s because of carbon dioxide “domes” that develop over urban areas. That finding, said researcher Mark Z. Jacobson, exposes an oversight in current cap-and-trade proposals for reducing emissions of heat-trapping gases. Those proposals make no distinction based on a pollutant’s origin.
“Not all carbon dioxide emissions are equal,” said Jacobson, professor of civil and environmental engineering. “As in real estate, location matters.”
His results support the case that California presented to the Environmental Protection Agency in March 2009, asking that the state be allowed to establish its own CO2 emission standards for vehicles.
Jacobson found that domes of carbon dioxide concentrations—discovered to form above cities more than a decade ago—cause local temperature increases. In turn, these increase the amounts of local air pollutants raising concentrations of health-damaging ground-level ozone as well as particles in urban air.
In modeling the health effects for the Lower 48 states as well as for California and the Los Angeles area, he determined an increase in the death rate from air pollution for all three regions compared to what the rate would be if no local carbon dioxide were being emitted.
The cap-and-trade proposal passed by the U.S. House of Representatives in June 2009 would limit the amount of greenhouse gases that each type of utility, manufacturer or other emitter is allowed to produce. It also would put a price tag on each ton of emissions, which emitters would have to pay the federal government.
If the bill passes the Senate intact, it would allow emitters to freely trade or sell their allowances, regardless of where the pollution was emitted.
With that logic, the proposal prices a ton of CO2 emitted in the middle of the sparsely populated Great Plains, for example, the same as a ton emitted in Los Angeles, where the population is dense and the air quality already poor.
“The cap-and-trade proposal assumes there is no difference in the impact of carbon dioxide, regardless of where it originates,” Jacobson said. “This study contradicts that assumption.”
“It doesn’t mean you can never do something like cap and trade,” he said. “It just means that you need to consider where the CO2 emissions are occurring.”
Jacobson’s study is among the first to look at the health effects of carbon dioxide domes. His results may be relevant to future air pollution regulations. Current regulations do not address the local impacts of local carbon dioxide emissions. For example, no regulation considers the local air pollution effects of CO2 that would be emitted by a new natural gas power plant. Those effects should be considered, he said.
Turning Wastewater Sludge Into Electricity
A University of Nevada, Reno renewable energy research project is moving from the lab to the real world in a demonstration-scale system to turn wastewater sludge into electricity.
The technology is scheduled to be set up in the Truckee Meadows Water Reclamation Facility next month following the signing of an interlocal agreement with the cities of Reno and Sparks.
The experimental carbon-neutral system will process 20 pounds of sludge per hour, drying it at modest temperatures into solid fuel that will be analyzed for its suitability to be used for fuel through gasification and, in a commercial operation, ultimately converted to electricity. The refrigerator-sized demonstration unit will help researchers determine the optimum conditions for a commercial-sized operation.
A full-scale system could potentially generate 600 kW of electricity a day to help power the relamation facility plant.
System installation begins in April and the system will be tested mid-May. The project will last until fall 2010.