Beijing’s hundreds of thousands of weeping willows and poplars have been a welcome source of shelter from the fierce summer sun for more than four decades – but they may also be an unexpected source of pollution, according to new research. Scientists warned that this urban greenery may be “choki...
Source: [SCMP](https://www.scmp.com/news/china/science/article/3365417/chinese-scientists-discover-trees-are-producing-ozone-smog-beijing?utm_source=rss_feed)