Key points from article :
Envinity Group has unveiled a large outside air purifier that can clean about 800,000 cubic metres of air per hour.
8m long steel industrial filter works like a big vacuum cleaner.
Sucks in air from a 300m radius and up to 7km above.
Filter out 100% of fine particles and 95% of ultra-fine particles.
About 90% of EU residents are said to be exposed to high levels of such particles.
