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Mosquito Control

Mosquito Control

Beware – mosquitos are around! With the first local dengue fever case confirmed recently, we should waste no time in mosquito control and dengue fever prevention. How to choose the right mosquito repellent amongst many products in the market? Earlier, the Consumer Council reviewed 45 mosquito repelling products, including mosquito repellents and anti-mosquito patches, and found that some products did not list their active ingredients and concentration levels. Read the followings for tips about mosquito control and prevention:

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The common active ingredients of mosquito repelling products are N, N-diethyl-3-methylbenzamide or diethyltoluamide (DEET), ethyl butylacetylaminoproprionate (IR3535), citronella oil, p-menthane-3,8-diol (PMD) and methyl nonyl ketone (IBI-246).

Different active ingredients and their concentration levels give different repelling results and effective protection duration. For products containing less than 10% DEET, the effective protection duration against mosquitos is limited to 1 to 2 hours only. But if the DEET level is raised to 30 – 35%, then the effective protection duration will be increased to 6 hours. 

The concentration of DEET for adults and children should not exceed 35% and 10%, respectively. The common side effect of DEET is contact dermatitis. Overuse of DEET could affect the nervous system causing spasm and nerve paralysis, etc. And in some rare cases, products that contain DEET may cause skin rashes.  Consumers who are allergic to DEET are advised to choose an alternative product that have similar effect but contain different active ingredients. 

  • The concentration of DEET for adults and children should not exceed 35% and 10%, respectively. There is no evidence showing that you could achieve better protection with higher concentration.
  • For daytime outdoor activities, sunscreen is applied. After 15 to 30 minutes, mosquito repellent is then applied.
  • Mosquito patches are usually adhered on to clothing or product surfaces. They can be changed in accordance with product instructions.CWash hands thoroughly afterwards.
  • Certain ingredients of mosquito repelling products may dissolve plastic materials.  For example, DEET and IR3535 could dissolve plastic materials and certain synthetic fibres. Touching items with plastic covers or parts such as mobile phones, cameras, handbags or plastic glasses frames with hands covered with products containing such ingredients may cause damage to these items.


For more information on mosquito repelling methods, please click here (Chinese version only).

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