The Liaowang Institute has published a new research article on Beijing's poplar catkins, explaining why they are so prevalent in Beijing every year.

In the report, the Institute notes a female poplar tree can produce about a kilogram of catkins during the spring breeding season. There are millions of female poplar trees in Beijing. While non-toxic, the report notes it also makes the whole city "crazy."

The poplar catkins are an annual spring phenomenon in Beijing. While some are able to ignore and even enjoy the annual release, not everyone shares this enthusiasm, particularly those who are allergic to it.

The report says the catkins in the air can pose a health threat to certain people, as well as fire hazard.

The catkins in the air can cause skin allergies, itching and red eyes. If they enter the respiratory tract, the dander can cause coughing and respiratory edema, and can severely aggravate those who suffer from asthma or chronic bronchitis. They can also carry pathogens, resulting in cross-infections.

They are also easily ignited. 10 square meters of the dander can burn out completely in just 2 seconds when exposed to an open fire. Back in 2017, there were reports of a number of fires caused by piled up catkins.