Property developers should publish buildings' ambient noise levels in promotional brochures for homebuyers, environmental officials have proposed. The Environment Protection Department said yesterday 1.1 million people in the city are estimated to live in a noisy environment, with the average noise level exceeding 70 decibels every hour. The department's website says noise that exceeds 70 decibels for six minutes in one hour - one-tenth of the time - is considered excessive. The department has received 400 complaints about road traffic noise in the past five years. In a report submitted to the Advisory Council on the Environment, the department suggested information on noise levels should be included in property brochures for potential homebuyers to make more informed decisions. 'Consumers should be notified when they purchase a flat how noisy the place can be so buyers can balance and compare the factors,' said council chairman Lam Kin-che after a meeting with department officials. No schedule or details of the proposal have yet been finalised but the council said it would study the topic with the government. But lawmaker Albert Chan Wai-yip, a member of the Legislative Council's environment panel, said the proposal, unless properly monitored, would be useless. 'Many estates comprise several blocks with lots of flats facing different directions - all with different noise levels,' he said. 'How can they provide you with a reliable figure without a monitoring system and a reliable formula? [Property developers] can easily distort the figures.' He also believed the proposal would not be supported by developers. As a general measure, the EPD has also proposed introducing more noise-absorbent material in road construction and improving existing road noise barriers.