UNIST Study Shows High Nighttime Ozone Levels in Rural Areas
- Yul So
- Jul 1
- 1 min read
July 1, 2025
Yul So
A research team from UNIST (Ulsan National Institute of Science and Technology) has found that high levels of ozone can remain in the air over rural areas during the night, not just in cities during the day.
Ozone is a harmful gas created when sunlight reacts with pollution in the air. It usually reaches its highest levels in the afternoon when the sun is strong. But this new study found that in some rural areas near cities, ozone stays in the air even after sunset and remains at a high level throughout the night.
The research team, led by Professor Jeongho Lim, developed a new artificial intelligence (AI) model to estimate ozone levels acros East Asia, 24 hours a day. Unlike older models, it can work even when the sky is cloudy. The AI uses different weather data like temperature, wind speed, sunlight, and satellite-based “brightness temperature.”
The model showed that brightness temperature was the most important factor in predicting ozone levels. This makes the model useful even in areas with no ground sensors, like many rural regions.
Ozone is very small—smaller than fine dust—and can enter deep into the lungs, possibly causing inflammation.Regular face masks can’t block it well.
Professor Lim said this model can help improve air quality monitoring and support future environmental policies, like seasonal ozone management.
The study was published on May 5 in the Journal of Hazardous Materials and was supported by the Ministry of Environment, the Ministry of Oceans and Fisheries, and the Ministry of Education in South Korea.
