Air quality alerts benefit asthmatics – Authors' reply

摘要

We appreciate the comments by Kaylee Ho and colleagues1 on our study,2 in which we evaluated the influence of an air quality alert programme on a wide array of health outcomes in Toronto, Canada. The Correspondence by Ho and colleagues presented an analysis using the 2007–10 National Health and Nutrition Examination Survey in the USA, showing that individuals who had asthma were more likely to change their behaviours in response to deterioration in air quality than those without asthma.3 Their finding adds to the ongoing scientific discussion as to whether an air quality alert programme might encourage avoidance behaviours (eg, reducing outdoor travelling and physical activities) on days with high levels of pollution.