What is the fine-grained topic of the following text: The World Economic Forum (WEF) claims there is “One beautifully simple action that municipal leaders can take to reduce both extreme heat and air pollution: plant more trees.” It further claims that planting trees “Is a one-two punch of environmental action.” This is due to the fact that trees and other green vegetation are responsible for naturally cooling the air around but also because they act as filters and are capable of reducing particulate matter (PM) levels in the surrounding 30 metres by as much as 25%. Only return the topic.
The beneficial effects of planting trees on reducing heat and air pollution.