Pollution does not respect borders.
This old adage is one of the first messages to arise from last week’s International Workshop for a Better Environmental Performance Index (EPI): Towards a Next Generation of Air Quality Monitoring – a workshop jointly hosted by Yale and Columbia Universities and the Asian Institute for Energy, Environment and Sustainability at the Seoul National University in Korea.
During a technical session on monitoring and modeling of heavy metals, Dr. Seung-Muk Yi of Seoul National University presented his research findings on the sources and movement of mercury in the Korean environment. His findings were stark.
Mercury is typically released into the air when fossil fuels containing mercury are burned for power generation. Though South Korean emissions of mercury are about one-tenth that of US emissions (18.5 tons a year compared to 143 tons a year), average blood mercury concentrations in Korean citizens are five times greater than average US concentrations.
As Dr. Yi presented, one-third of Koreans have blood mercury levels above those deemed safe by US health guidelines – putting them at risk for neurological health effects and neurodegenerative disorders.
What accounts for this looming public health threat?
Two phenomena combine in Korea to create this potential health disaster:
1. Koreans consume a lot of seafood (74-95 grams a day, about five times the US average); and
2. Korea is near China.
According to Dr. Yi, China’s annual emissions of mercury are nearly four times greater than the US’s and nearly 30 times greater than Korea’s.
By tracing mercury concentration changes over time across monitoring sites within Korea, scientists in Seoul were able to implicate Chinese emissions in Korea’s pollutant problems.
“As our local emissions went down [following new regulations],” he said, “mercury concentrations in our rural and remote stations remained constant.”
China contributed the most to our high mercury events, he said, noting that more than 60 percent of high mercury events in Seoul, when government air monitors detected unusually acute mercury levels in the air, were the result of air masses carried from China.
Coal combustion in Hunan, metal smelting in Guizhou, and dust storms in the Gobi Desert were all implicated in Korea’s pollution problem. Meaning what happens in China doesn’t stay in China.
Lessons like this – an old lesson made new - underscore the importance of international workshops like this one where atmospheric scientists, chemical engineers, and policy experts from around the world wrestled with the very modern problem of global pollution. Hopefully, the knowledge generated here in Seoul won’t stay here.