According to long-term research carried out by several medical schools, children who are exposed to relatively large amounts of sulfur dioxide, nitrogen oxides and ozone are more likely to suffer from asthma by the age of three.
根據多所教學醫院長期的追蹤研究發現，新生兒在一歲以前暴露於較多的二氧化硫、二氧化氮及臭氧中｝滿三歲時，罹患氣喘的比率較高。