Interesting enough to be worthy of a thread. Perhaps this will be tried in the US in the 2020s.
China’s 30 story tall air cleaning tower is a successful test for many150 story air cleaning towers
China has created an experimental air purifying tower that is over 100 meters (328 feet) tall in northern China. It reduces 2.5 micron air pollution by about 15% over a 10 square kilometer area.
The system works through greenhouses covering about half the size of a soccer field around the base of the tower.
Polluted air is sucked into the glasshouses and heated up by solar energy. The hot air then rises through the tower and passes through multiple layers of cleaning filters.
The Xi’an smog tower project was launched in 2015 as a trial version of a much larger system the research team hopes will be implemented in other Chinese cities in the near future. It barely requires any power input throughout daylight hours. The idea has worked very well in the test run. The full-sized tower would measure 500 meters (1,640 feet) tall and 200 meters (656 feet) in diameter, with greenhouses covering nearly 30 square kilometers (11.6 square miles). This system is hoped to be powerful enough to purify the majority of the air within a small city.