Fine Dust, the Key is Science and Technology!

By Science Columnist Hyung-Ja Kim

The world is now confronted with fine dust, which can be called a “crisis.” The scientific community is focusing on how to make clean air using various technologies. Some of the latest technologies have gained attention by showing the possibility of reducing fine dust.

The Chinese Academy of Sciences has set up a 100-meter tall giant air purifier called "Chumaita" (smog eliminating tower) outdoors in Xian City of Shaanxi Province. It's the world's largest fine dust reduction device. It looks like a big chimney. At the bottom, which looks like a floor, is a glass greenhouse that is half the size of a soccer field; it has a simple structure just like a chimney with a discharging tower (chimney) at the center above the greenhouse, which looks like an upside-down funnel.

The principle of operation is also simple. First, polluted air around the tower is sucked in through inlets (large motors) installed on the outside walls of the glasshouse in four directions. Then the solar heating panels on the floor warm up the dirty air that has been sucked into the greenhouse from outside.

The hot air is sucked up into the discharging tower of the central column, the chimney hole, by a convective process. Going through various filter devices at the top of the chimney, ultra fine dust as well as pollutants such as nitrogen dioxide and sulfur dioxide are filtered out, and clean air is discharged. It is the principle that hot air escapes and contaminated cool air replaces the hot air over and over again, turning the surrounding air into fresh air. It requires little electricity, because it runs on solar heat.

Xian is the largest industrial city in China and produces coal. There are still a lot of households using coal for heating, positioning the city as one of the most air-polluted cities in China. Nowadays, thanks to this air purifier, citizens are breathing clean air. Areas within 10 ㎢ from the giant air purifier are provided with 10 million ㎥ of clean air every day, reducing a whopping 15% of the fine dust concentration. The area is equal to that from Gangnam Station to Yeouido Station (9.5㎞). It is said that Xian citizens are very satisfied with the effect.

The technology of the Netherlands using the polarity of fine dust also attracts attention. Artist and inventor, Daan Roosegaarde, made headlines by setting up a "Smog-free Tower" that can purify 30,000 ㎥ of air per hour at a height of about 7 m in Rotterdam.

This tower works based on the principle that coils buried under the ground generate static electric fields, attracting fine dust onto the ground. It is the same principle as a writing plastic sheet having static electricity collecting dust. This tower was also effective for reducing fine dust. For 41 days, it purified 30 million ㎥of air. The effect was so huge that it can be found in every corner of the city, like traffic lights in the future.

There is also this technology that reduces fine dust using an electric precipitator. “Micro Pulse System (MPS)” is a typical example of industrial environmentally-friendly systems. With MPS, fine dust is removed by using an electrostatic force created with high voltage pulses and attracting fine dust to the collecting plate. MPSs are usually installed in dust chambers where fine dust is collected in industrial sites, including thermoelectric power plants and steel mills that emit air pollutants. China, which suffers from smog, has installed them in large thermoelectric power plants and steel mills in Qinhuangdao, and Korea has also made it mandatory to install them in major facilities such as power plants and steel mills as well as oil refineries to prevent air pollutants from being emitted.

Yellow dust masks keep evolving; there are now masks that filter air primarily through nanotechnology. Made with new nanofiber material entangled like a spider web, they are not only strong against humidity but also good for breathing and effective for removing fine dust. Conventional yellow dust masks had the disadvantage that the effect degraded as you breathe because they were made with filters using static electricity. Now that a prototype has been produced, I suppose we can expect to wear a yellow dust mask equipped with nanotechnology soon.

These days, drones (UAV) are used for removing fine dust. Hundreds of drones equipped with fine dust removal filters fly over and filter dust. They can also be operated for a long time by charging them frequently at drone charging stations installed in the air like hot air balloons. Furthermore, research is underway to let fine dust fall like rain by spraying fine dust coagulant with drones in the sky. It is expected to show an effect, as it is a technology of global interest.

Scientists around the world will continue to develop a variety of technologies to reduce fine dust. The most important thing, however, is our interest in creating a clean Earth. With the public efforts along with scientific technology for ”conquering” fine dust, we will be able to breathe clean air all the time.