Public health concerns rose Monday as yellow dust from China prompted the government to issue alerts for the second day running.

This year’s first yellow dust warnings swept the capital and a dozen surrounding areas after the advisories were issued and elevated Sunday, the Korea Meteorological Administration said. It was the capital’s fifth yellow dust warning since 2002. 

At 4 a.m. Monday, the dust concentration in Seoul reached 1,044 micrograms per cubic meter, the fourth-highest since 2002, when the government started to collect such measurements.

Ganghwado Island in Incheon coast recorded 707 micrograms per cubic meter, followed by Chuncheon, Gangwon Province, with 696 micrograms per cubic meter, the weather agency said.

Yellow dust advisories are issued when an hourly average dust concentration of more than 400 micrograms per cubic meter is expected to continue for more than two hours. More than 800 micrograms per cubic meter for over two hours triggers a warning.

“The yellow dust, which originated from deserts in southern Mongolia and northern China, flew to the peninsula on a strong northwesterly wind, leading to thick yellow dust,” the KMA said.

At 4 p.m., the weather agency eased the warnings to advisories in Seoul and surrounding cities as the concentration of the dust gradually dropped. But some areas will still likely see light yellow dust Tuesday, the weather agency added.

Citizens were advised to stay indoors and wear protective glasses and masks in case of outdoor activities, health authorities said. They also advised people to frequently wash their noses with running water to prevent respiratory problems.

Along with yellow dust warnings, Seoul Metropolitan Government also issued the year’s first ultrafine dust advisories as of 1 a.m. Monday as the hourly average level of the ultrafine particles or PM-2.5 continued to stay over 120 micrograms per cubic meter for more than two hours, officials said.

The concentration of PM-2.5 once reached 196 micrograms per cubic meter in Gangseo-gu, the highest regional level, they added.

Ultrafine dust advisories were also issued in Gyeonggi Province.

By Lee Hyun-jeong (rene@heraldcorp.com)