Republic of South Korea faces a battle against unhealthy air, caused by a combination of domestic emissions from coal-fired power plants and cars, and pollutants wafted in from China and North Korea.

The amusing fact is whenever dust particles hang thick in the air in South Korea, sales of pork rise.

This quirky correlation in Asia’s fourth-largest economy, where air pollution outstrips industrialized peers, stems from an old belief attributed to coal miners, that the slippery pork oil helped cleanse dirt from their throats.

For middle school student Han Dong-jae, eating greasy barbecued pork belly on a smoggy day is a life lesson imbibed from his mother.

“I eat more pork when fine dust is dense like today,” said the 15-year-old as he dug in over a sizzling grill at a barbecue restaurant in Seoul with his mother after school.

“I think it’s somewhat helpful, because pork meat has oil and the oil soothes my throat.”

Scientists say there is no rationale for the belief, but pork sales jumped about a fifth on the year from Feb. 28 to March 5, when pollutants blanketed most areas, data from major retailers E-Mart and Lotte Mart showed.