Thus one kind of tiny but invisible insect which can trigger allergic responses has gone from 100 per gram of dust in old wooden style houses to 1000 per gram today.
一種引起過敏疾病、肉眼難見的小蟲「」，就由過去舊式木造房屋中，一公克塵埃含量不及一百隻，增為今天的一千隻。