§ Mr. Simon HughesTo ask the Secretary of State for the Environment what steps Her Majesty's Government are taking to encourage infra-red aerial photography in areas in danger of leakage of methane gas from rubbish tips; and if he will make a statement.
§ Mr. Moynihan[holding answer 29 June]: Her Majesty's Inspectorate of Pollution is currently investigating various techniques for monitoring the production and migration of methane gas at landfill sites.
The taking of aerial photographs, both colour and infra-red, can assist in detecting the changes in vegetation due to migrating gas over an area around a landfill site. Infra-red cameras can be used to measure heat emission from the ground surface. However, this type of survey has to be carried out at night to avoid interference from the sun. The hot spots detected can be physically marked on the site during the survey, which can then be monitored with instruments. This technique detects only excess heat, which could be due to causes other than gas emission.
Advice on this technique will be included in the waste management paper planned for publication later this year.