Ozone threat off radar

By Kang Seung-woo

As fine dust is becoming an overwhelming public health challenge in Korea, dealing with rising ozone levels that cause serious respiratory problems has been put on the backburner.

According to the National Institute of Environmental Research (NIER), Wednesday, 26 ozone alerts have been issued since the first one this year on April 19. In particular, cities in the northern region of Gyeonggi Province including Uijeongbu and Gimpo saw an alert issued for the second consecutive day, Sunday and Monday, after the ozone level exceeded national standards.

However, the government has yet to find the cause of the higher ozone levels or come up with countermeasures, with all its efforts directed toward fine dust that is also emerging as a serious environmental issue.

Ozone is formed when volatile organic compounds and nitrogen oxides from cars and fossil-fuel power plants are heated in the atmosphere by sunlight. The gas cannot be blocked by facemasks that are used against fine dust.

The ozone layer protects people from ultraviolet rays that can harm the skin. However, if it is too thick in the air, it can generate photochemical smog that can affect people with respiratory diseases such as asthma.

“Despite growing ozone levels, it has drawn little attention as government-wide efforts are being concentrated on fine dust,” University of Suwon professor Jang Young-kee said.

“The government is required to uncover the root cause of rising ozone density and seek measures to reduce it.”

With little focus on ozone levels, the issue is lurking behind the scenes.

After taking a sharp jump from 66 in 2012 to 160 2013, the number of ozone alerts issued has seen a steady upswing. In 2016, alerts were sent on 241 occasions, followed by 276 last year.

To make the situation worse, the timing of the first ozone alert is getting earlier. From 2005 to 2013, it was issued in April only twice ― in 2008 and 2009 ― but since then, every year except for 2016 has seen its first ozone alert in April.

The statistics come as this year is expected to see higher levels because the “ozone season” ― usually from May to July ― is likely to see high temperatures and less rain, allowing more of the gas to be produced.

“The ozone levels have increased every year and considering weather conditions, we could have more concentrated ozone this year,” said Chang Lim-seok, an NIER senior researcher.

The warning system for ozone is graded in three categories ― alert, warning and heavy warning. In the alert stage where the density is up to 0.12 parts per million (ppm) per hour, physical training and outdoor classes are restricted. In the warning stage ― a density up to 0.3 ppm ― outdoor activities at kindergartens and grade schools are banned. In heavy warnings with a concentration of 0.5 ppm or above, schools should close for the day.