Many cities around the world are suffering from severe air pollution. The World Health Organization (WHO)’s urban air quality database reveals that about half of the global urban population is exposed to air pollution that is at least 2.5 times higher than recommended levels. These intense levels of smog are making people vulnerable to respiratory diseases and other health problems.

In light of growing concern worldwide about urban air pollution, the Palazzo Italia at Expo Milano 2015 is gaining huge attention for its “smog-eating” façade. 9,000 square meters of concrete are mixed with photocatalytic substances that use sunlight to break down pollutants, which are then washed away with rainwater.

Here at TheCityFix, we’ve compiled some of our favorite examples of how innovative building designs and technologies can help purify city air.

Mexico City and Bogota’s Smog Eating Buildings

Despite significant improvement in recent years, Mexico City still faces high levels of air pollution. In the often-smoggy downtown, a hospital building called the Torre de Especialidades is shielded by a façade made with special tiles that have the ability for “air-scrubbing”. The secret of this concrete is titanium dioxide, which interacts with organic compounds on the surface and the air, oxidizing and breaking them down into carbon dioxide and water molecules that wash away with a small amount of moisture. It is estimated that the building can suck up pollutants equivalent to the amount produced by 1,000 cars each day.

Although the hospital’s smog-eating technology is only one step toward solving a citywide problem, the innovative design has been proven that it can provide fresher air in the surrounding neighborhood.  The Torre de Especialidades designers hope to inspire other hospitals and major buildings to follow their lead.

Designers have indeed noticed. A similar smog-eating material has also been used in Bogotá, Colombia, the second largest city in South America, where more than 1.5 million cars and 100,000 public service vehicles use diesel fuel.

An Air-Purifying Billboard in Lima, Peru

Lima experiences extreme air pollution, caused largely by the transport and industrial sectors. The city’s pollution levels are triple the maximum recommended by the WHO. The situation is exacerbated by a booming construction industry in Peru.

Some people have taken a stand and are taking steps large and small to improve their city’s air. A air-purifying billboard designed to improve air quality near construction sites is currently serving the Barranco section in Lima. Its creator, the University of Engineering and Technology of Peru (UTEC), estimates that between March 24-30 in 2014, 49,800 city residents benefitted from 489,000 cubic meters of purified air, and that the billboard managed to eliminate 99 percent of the airborne bacteria.

Manila’s Air Cleaning Murals

Instead of constructing new buildings with these new technologies, Manila is painting murals with an air-cleaning paint along the walls of the city’s busiest streets. The city recently invited ten artists worldwide to design murals covering over 8,000 square meters of walls, columns and bridges along the Epifanio delos Santos Avenue (EDSA). Studies have shown that this unique green paint has reduced air pollutants by more than 18 percent in the surrounding area.