Smog Tower

A smog tower is a large outdoor structure built to draw in polluted air and filter out fine particulates before releasing cleaner air back into the surrounding area, typically using fans to pull air through layers of filters or, in some designs, using the natural upward draft created by heated air. They have been built and tested in heavily polluted cities such as Delhi and Xi'an as a way to address smog directly at street level, though their effect is limited to a relatively small area around the tower compared with the scale of a city wide emissions. Reviews of early installations have generally found their measurable impact on citywide air quality to be modest, which has kept the technology at an experimental and demonstration stage rather than widespread deployment.