The legal requirement to issue pollution alerts rests with the Secretary of State (under regulation 21 of the Air Quality Standards Regulations 2010) rather than the Mayor of London. The Secretary of State has a duty to inform the public by means of radio, television, newspapers or the internet if information thresholds for sulphur dioxide nitrogen dioxide and ozone (as set out in schedule 5 to the regulations) are exceeded. The Secretary of State provides online information to the public on current and forecasted air quality at:
http://uk-air.defra.gov.uk at all times, and this meets the requirements of this duty. In addition, a freephone service is available.
DEFRA has also undertaken to issue a press release when the first ozone episode occurs each year. This is to draw attention to the online information services available and remind the public of where to find more details. The decision on whether to issue a press notice is reviewed each year.
In addition to this, the Mayor of London has voluntarily promoted a pioneering new airTEXT service whereby people living in London can get free text, email or voicemail alerts of elevated levels about air pollution.