Can telling people about air pollution lessen the impact? A new air quality index was launched in Hong Kong at the end of 2013. This included forecasts and information for vulnerable people; doctors were enlisted to advise their patients too. A new analysis of seven years of data showed that the start of the index was followed by a 16% reduction in the number of children treated in hospital with respiratory infections and pneumonia. This was attributed to parents following official advice to keep their children indoors during smogs. However, the benefit was short-lived and lasted for only about a year. Other studies have also found that people are willing to adapt their lives for short periods to protect themselves but not in the longer term. No effect was seen in elderly people. This was thought to be due to low literacy rates and difficulties in reaching them with information.

Others have criticised indices for focusing on smogs rather than the more harmful exposure to low levels of air pollution every day. Asking people to adapt to poor air pollution may help but we need to solve the problem at source. Our lives should not be further compromised by adapting what we do because of the quality of our air.