In addition, as a result of urbanization, an ever growing number of high-rise buildings are being erected in which dust particles and other allergens circulate in closed central air conditioning systems.
此外，都市化的結果，玻璃帷幕大樓林立，大樓裡的中央空調，讓諸如灰塵、塵 (等過敏原一直循環在室內排不出去，更是過敏族揮之不去的夢魘。