How do you keep mozzies at bay? SAMANTHA ANN YOUNG finds out.
Keep those pesky mosquitoes at bay.
For repelling mosquitoes, electric vaporising devices that release repellents through smoke or heat, as well as mosquito coils, are more effective than devices that use ultrasonic and electromagnetic waves, says the National Environment Agency.
WHAT WORKS Mosquito coil
HOW IT WORKS A lit mosquito coil – which can smoulder for up to eight hours – releases insecticide smoke into the air to repel mosquitoes. AREA OF COVERAGE A 7m radius around the coil in a closed room, according to a study by Mahidol University in Thailand. USING IT The Thai study found that the coil should be lit for at least an hour for it to be most effective. However, a 2003 study on the health implications of mosquito coils, by researchers from the US and Malaysia, found that coil smoke contains ultra-fine particles that could be harmful to health. To avoid inhaling the smoke, it’s probably best to leave it to burn in your bedroom to get rid of any mosquitoes, then douse it before you enter the room. BUY IT Baygon Mosquito Coil, 76 cents, from major supermarkets.
Electric liquid vaporiser
HOW IT WORKS An electric heater vaporises insecticide from a bottle. The liquid insecticide may last about a month when used eight to 10 hours a day. AREA OF COVERAGE One vaporiser can usually cover a room with an area of up to 10 sq m (the size of a small bedroom). USING IT The Hong Kong Agriculture, Fisheries and Conservation Department recommends using it with windows slightly open. BUY IT Baygon Liquid Electric Repeller, $6.40, from major supermarkets.
WHAT MIGHT WORK Mosquito-eliminating device that emits heat and carbon dioxide
HOW IT WORKS Such devices lure mozzies by emitting heat, carbon dioxide and a UV black light. A suction fan then sucks the insects into a cage where they are left to die. AREA OF COVERAGE Ranges from 15 sq m to 200 sq m – from an HDB flat bedroom to two five-room flats. USING IT Place it 1m to 1.2m above the ground, suggests Zarah Lee, business development manager of Olee International, the distributor of Pest-Stop, a brand of pest-control products. “That’s the optimum flying height of mosquitoes,” she says. Use one for each room – in the middle, if you can, to increase the possibility that mosquitoes will fly across it and get sucked into the machine. BUY IT Pest-Stop Photocatalyst Mozzie Magnet, $89.90 to $129.90, from Home-Fix and Selffix.
WHAT DOESN’T WORK Pest-repelling device that uses ultrasonic and electromagnetic waves
WHY NOT? These devices are more suitable for repelling creepy-crawlies such as ants, cockroaches and lizards.