Air quality alerts benefit asthmatics

摘要

We have read with interest theArticle by Hong Chen and colleagues, 1particularly the evidence of reductionsin asthma-related emergency-depart-ment visits associated with air qualityalert programmes in Toronto (ON,Canada). We have compared changesin activity between people withasthma and people who do not haveasthma using representative datafrom the 2007–10 National Healthand Nutrition Examination Survey inthe USA.