For green activists with an eye for energy issues, one of the easiest targets is light bulbs. Most of the bulbs we use in our homes are not energy efficient and that means increased carbon emissions. Greenpeace and other environmental watchdogs have been pushing hard for the Hong Kong government to follow the lead of other countries and regions, such as Australia, Chile and the European Union, and phase out traditional incandescent light bulbs to make way for their green equivalents.
The argument seems compelling. In 2007, Greenpeace put the case that replacing incandescent light bulbs with compact fluorescent light bulbs (CFLs) - as the pricier green bulbs are known - would cut carbon dioxide emissions by 480,000 tonnes in the city annually.
Small surprise then that, while the campaign has not been a success in making CFLs mandatory, Hong Kong consumers have begun to embrace the green light sources. According to the Environment Protection Department, an estimated 3.5 million CFLs are sold annually in the city. The downside is that the department also estimates that up to 3 million used CFLs are discarded every year.
'Green' CFLs contain minute amounts of mercury - around 5mg per bulb on average. Mercury is extremely toxic. It is dangerous even in small quantities because if it is inhaled or absorbed through your skin, it affects the central nervous system. When the bulbs are thrown away and leak into landfills, over time, the mercury can find its way into the soil and enter the food chain.
'CFLs contain mercury, which is poisonous,' admits Man Chi-sum, chief of Hong Kong environment watchdog Green Power. 'When a bulb breaks at home, children should be kept away from the pieces.'
One British government advisory has gone further, urging people to leave and seal up any room in which a CFL breaks for 15 minutes. The United States Environmental Protection Agency presents a less dramatic solution in the event of a breakage, advising: 'Open nearby windows to disperse any vapour that may escape, carefully sweep up the fragments [do not use your hands] and wipe the area with a disposable paper towel to remove all glass fragments. Do not use a vacuum [cleaner]. Place all fragments in a sealed plastic bag.'