Hwang Mi-sun used to watch over her baby son as he slept at their home in Seoul, to listen to every laboured breath.
From a young age he suffered from respiratory problems.
He’s now four years old and has been given various drugs including strong steroid treatment to try to help. But after his fourth trip to hospital, the doctor had another piece of advice.
Mrs Hwang was told to keep her young son inside to save him from South Korea’s toxic air.
“It was sad that my child started to learn not just words like mum and dad, but also fine dust so early on,” she told me. “I even thought moving out of the country but I really want to live in Korea. So I’m going to do whatever I can help to solve the problem.”