Urban green as prevention of the heat island effect and smog formation

Central Park in New York © Maria Isabel Villamonte, Dreamstime.com

Urban green demonstrably lowers the air temperature in a city. A direct link can also be made between the formation of smog and air temperature. Warm air carries pollution and particulate matter to higher layers of air, causing a cloud of smog. Cooler air from outside the city is heated at the city limit and does not penetrate into the city centre. At night this warm air pocket causes an inversion, resulting in an inability of the city to cool down, and clean air from outside of the city is not able to mix in. Krusche et al., 1982

The formation of smog during day and night impact on air temperature in the city © Krusche et al., 1982
Prague, Czech Republic © Alexander Vasilyev, Dreamstime.com