One of the Committee’s recommendations is that the Government works more closely with the Met Office, the BBC and other broadcasters to ensure that forecasts of high air pollution episodes are disseminated widely together with advice on what action should be taken. The Committee’s rationale is that information about air pollution allows individuals to take action that reduces exposure. However, avoidance behaviour, such as staying indoors, imposes a cost on individuals that might exceed the perceived gains.
|A BBC weather forecast for Bristol showing the commonly |
encountered “green” air pollution forecast.
In a paper published this month in the Journal of Health Economics (Link with free access until 22 January 2015) I investigate responses to air pollution warnings in England. I obtained data on the air pollution forecasts issued by Defra from 2002 to 2008. During this period the daily air pollution forecast was freely available via the internet, a Freephone telephone service, Teletext and with the weather forecast on the BBC website. The forecast was disseminated using traffic light colour-coding, with green indicating low levels of air pollution, amber moderate and red high levels. “Red” forecasts were extremely rare (3% of forecasts) and “green” forecasts very common (70% of forecasts), so a change from “green” to “amber” (27% of forecasts) was akin to an air pollution warning. Hence, I define an “amber” or “red” forecast as an air pollution warning.
Air pollution warnings and hospital emergency admissions
|Image from medicaldaily.com|
Looking at all respiratory admissions I found no effect. Looking at a subset of respiratory admissions - admissions for acute respiratory infections such as pneumonia and bronchitis – I also found no effect. Only when I examined another subset of respiratory admissions, namely admissions for asthma, did I find that air pollution warnings reduce hospital emergency admissions, by about 8%.
Presumably, it is less costly for asthmatics to respond to an air pollution warning. Standard advice for asthmatics is to adjust the dose of their reliever medicine and to make sure they carry their inhaler with them. Other types of respiratory disease require far more disruptive preventive measures such as staying indoors, making the cost of responding to air pollution warnings larger than the perceived gains.
Direct evidence of avoidance behaviour: visitors to Bristol Zoo
This blog is written by Cabot Institute member Katharina Janke, Research Associate in Applied Microeconomics and Health Economics at the Centre for Market and Public Organisation at the University of Bristol.