Ozone That Cannot Be Blocked by Masks: How to Protect Yourself?

Ozone is a gas composed of three oxygen atoms, formed when an oxygen molecule bonds with an oxygen atom. In the ozone layer, which lies between 20 and 30 km above the Earth's surface within the stratosphere (ranging from 10 to 50 km in altitude), ozone absorbs harmful ultraviolet rays and prevents them from reaching the ground. However, in the troposphere, which is closer to the Earth's surface, ozone can have negative effects on our health.

Ultraviolet rays

According to the first Climate Health Impact Assessment Report by the Korea Disease Control and Prevention Agency, the annual average concentration of ozone increased from 35.8 ppb in 2010 to 45.0 ppb in 2019. The number of excess deaths due to short-term ozone exposure also nearly doubled, rising from 1,248 in 2010 to 2,890 in 2019.

Repeated exposure to ozone can negatively affect the lungs, causing symptoms such as coughing, nausea, and chest pain. In severe cases, it can worsen conditions like asthma, chronic obstructive pulmonary disease, heart disease, and bronchitis. Vulnerable groups such as the elderly, infants, children, people with respiratory or heart diseases, and pregnant women are particularly sensitive to ozone and should take extra precautions.

Kim Yunmi, Director of the Comprehensive Health Checkup Center at Daedong Hospital and a specialist in family medicine, stated, "Climate change brings many factors that negatively impact health, but compared to fine dust, there seems to be less attention paid to ozone. Ozone also directly affects our bodies, and unlike fine dust, it cannot be blocked by wearing a mask, so we need to be aware of it. As summer approaches, strong sunlight and weak winds cause various air pollutants to undergo photochemical reactions, leading to high concentrations of ozone. Therefore, it is important to know and practice preventive measures to avoid ozone exposure," she advised.

Currently, an ozone forecasting system is in place to alert the public in advance about high ozone concentrations, so it is recommended to check ozone levels before going outdoors.

If the ozone forecast level is "moderate" (0.031?0.090), there are no special restrictions, but sensitive groups should be cautious according to their condition when going about daily activities.

If the level is "bad" (0.091?0.150), avoid prolonged outdoor activities, and if your eyes hurt, refrain from going outside. Sensitive groups should limit outdoor activities, and if going out is unavoidable, avoid the hours between 2 p.m. and 5 p.m. when solar radiation is highest. At "very bad" levels (0.151 or higher), everyone should avoid outdoor activities and stay indoors.

When ozone concentration is high, it is also recommended to use public transportation instead of private cars, and to avoid refueling, dry cleaning, painting, or using sprays during hot hours.