In their search for the causes of asthma, scientists have blamed lots of disgusting stuff, like roach parts and mite scats. They've also found a few asthma triggers that aren't so disgusting, like cold, dry air. And even a few that should be healthy, like exercise. Many, indeed most, cases of asthma, particularly among children, have allergies as a major component.
Different people have different allergies, obviously.
Let's stick with this el-grosso train of thought by looking at some of the more revolting asthma triggers. Similarly, bacterial sinus infections can aggravate asthma by causing mucus to drain into the lungs. Chemicals such as strong perfumes, household cleansers, or industrial dusts and vapors can all irritate the lungs. 50 percent of the kids' rooms contained roach allergen, compared to 10 percent containing dust-mite allergen.