Dust Warning: Too Little, Too Late?

It was revealed that at the point of a forecast alert on the level of yellow dust in Korea, the minute dust particles had risen dramatically and were at their highest density.

This means that before the forecast was announced, people were inhaling harmful amounts of substances, calling for an immediate solution.

It was also discovered that the yellow dust in China had absorbed pollutants in the air above major cities, and as it moved into the Korean peninsula, chemical reactions occurred to make it fall like ash.

At the request of the Korea Science and Engineering Foundation, the Inha University yellow dust research team recently made a report called, “Revealing the Long-Distance Reaction of Yellow Dust Particles.”

April 8 marked the most severe case of yellow dust in history, dubbed the “Yellow Dust Attack.”

At that time, the meteorological office sent out a yellow dust alert at 1:30 p.m. However, according to the Inha University research team, the minute dust particles that were usually around 5,000,000 per m³ had increased to 8,000,000 at noon the day before.

The minute dust particles continued to skyrocket afterwards, abating one-and-a-half hours after the yellow dust alert when it was at its highest (21 million).

The minute dust particles are the minute dust which is mixed with pollutants like NOx and SOx, and cannot be filtered out by masks. They are later absorbed in the lungs due to their size of 0.5 to 1.0μm. One μm is 1mm divided by 1000.

Most people have started to wear masks and have refrained from outdoor activities after the yellow dust alert was released, but it was already 10 hours after they had breathed in all the dusts.

This phenomenon on yellow dust was similarly recorded in both 2002 and 2005.

A professor of preventive medicine at The Catholic University of Korea, College of Medicine, Rhim Young, says, “The reason yellow dust is so harmful is because the minute dust particles cannot be filtered out with masks. When it is inhaled and moves into the bloodstream into the heart, it can set off a myocardial infarction.”

The research team also discovered for the first time that when yellow dust passes over Beijing and other industrial cities in China, CaCO₃chemically reacts to pollutants such as oxidized nitrogen or sulfur in the atmosphere.

Due to the chemical reactions, the Ca(NO)₂ or CaSO₄ mutate into harmful substances and are sprayed over the Korean peninsula in very much the same way ash rains down after an atomic bombing.

The research team accordingly emphasized the importance of solutions such as reinforcing the measuring standards of minute dust particles and advancing the date of alerts to lessen the damage of yellow dust.

Jun-Ho Cha run-juno@donga.com