It’s not difficult to recall to mind images of Chinese citizens going about their daily business with surgical masks across their faces in an effort to filter the air that they breathe in the many highly-polluted cities in that country.
Xian is one of China’s most polluted cities, however, a 60-metre-high chimney that stands among the high-rise buildings is not adding to the smog but is helping to clear the air. Powered by the Sun, this giant outdoor air-purifying system sucks in polluted air at the bottom and heats the air so that it rises. As the air moves upwards it passes though a number of filters, which purify it, leaving only clean air to waft out into the city sky. Chinese scientists who designed the prototype say that the system could significantly cut pollution in urban areas in China and elsewhere.
“The Solar-Assisted Large-Scale Cleaning System (SALSCS) consists of a circular or rectangular based green house with glass panels that gradually rise toward the center tower,” Professor David Y.H. Pui, one of the researchers on the project, told Digital Trends.
“The SALSCS glass panels are coated with nanoparticles to remove nitrogen oxides, one of the major precursors of PM2.5 and ozone.”
PM2.5 refers to particles with an ultra-fine mass of less than 2.5 micrometers. This is known to be very dangerous to humans and can increase mortality risk, particularly from cardiovascular causes.
The project is currently in the testing stage. However, the results of earlier trials have shown that the purification tower does have a positive effect on air quality.
Source: Digital Trends