Reducing China’s CO₂ Emissions Would Curb Deadly Air Pollution in the U.S.

China's pledge to cut its carbon dioxide emissions beginning in 2030 includes a generous gift for its downwind neighbors: less deadly air pollution.

By 2030, there will be nearly 2,000 fewer premature deaths in the United States from inhaling pollutants emitted in China, according to a study by the Massachusetts Institute of Technology. South Korea and Japan are also expected to benefit.

"It reminds us that air pollution doesn't stop at national boundaries," said Valerie Karplus, a co-leader of the study and an assistant professor of global economics and management at MIT.

The study, which was published in the journal Environmental Research Letters, used computer models that track pollutants and data from global health statistics.

Needless to say, China will be the main beneficiary if it is able to curb its emissions, primarily by departing from its heavy reliance on coal and other fossil fuels. According to Chinese studies cited by the new research, carbon-cutting policy solutions could cut between 55,000 and 94,000 premature deaths by 2030.

Nearly 60% of these deaths would have come from inhaling what scientists call PM2.5, or tiny particles that can invade the human body. The remaining 40% would have been caused by inhaling ozone, a toxic gas that forms when pollutants are heated in the lower atmosphere by sunlight.

The study, which partly focused on pollutants from China that drift over the Pacific and then over the United States, showed that fine particles — which would cause most of the premature deaths in South Korea and Japan — tend to become diluted before they arrive here in the United States. Ozone, on the other hand, remains more potent and would have caused most of the avoided 1,900 premature U.S. deaths.

Karplus said the study fills a gap by showing the health benefits to China's neighbors from its policies to reduce carbon dioxide emissions. It demonstrates that China, the world's largest emitter of CO2, will create political benefits for its neighbors as well as for itself by curbing the greenhouse gas.

Karplus said the findings could trigger more interest in other countries to help China find more innovative ways to curb its CO2 emissions.

"This is definitely a way to push for greater ambition," she said.

The study shows how the chemical ingredients of pollution — including sulfur dioxide, nitrogen oxides, black carbon, carbon monoxide and volatile organic compounds — react with each other and sunlight to create the deadly drift of PM2.5 and ozone.

It uses records from the mortality database of the World Health Organization to predict the rise and fall of resulting diseases. For example, inhaling PM2.5 can cause heart disease, cerebrovascular disease and lung cancer.

Globally, according to a 2010 estimate, exposure to outdoor air pollution including PM2.5 and ozone caused 3.3 million premature deaths.

The MIT study noted that the percentage of health benefits enjoyed by the United States and China's other downwind neighbors will continue to grow as China keeps putting in place its pledged emission cuts between 2030 and 2050. The study discusses three policy scenarios that could lower CO2-related pollutants and their costs as a fraction of China's gross national product.

A second MIT study released this week shows how India — another nation emitting large amounts of CO2 from fossil fuels — could combine an economywide price on carbon emissions with a renewable portfolio standard to meet its pledge to reduce emissions and increase its carbon-free power by about 40% of installed capacity in 2030.

The study, which appears in the journal Climate Change Economics, estimates that "declining wind and solar costs could enable India to set more ambitious climate policies in future years without significantly impeding economic growth."

It notes that India's economy is "booming" and that its electricity production, which increased by five times in the past three decades, would triple in the next 20 years as India struggles to meet its climate pledge. The nation has promised to reduce its carbon dioxide emissions by 33% to 35% by 2030 compared with 2005 levels.

Karplus, who also co-authored this study, noted that globally it has been "politically impossible" to get carbon prices high enough to meet the Paris Agreement's CO2 goals.

Coupling cheaper renewable energy sources with an increased carbon tax "may be important in India, as they have elsewhere, for the politics to work," she said.

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.