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Mosquito coil

A mosquito coil is a mosquito repelling incense , usually shaped into aspiral, and typically made from a dried paste of pyrethrum powder. The coil isusually held at the center of the spiral, suspending it in the air, or wedged bytwo pieces of reproof nettings to allow continuous smoldering. Burningusually begins at the outer end of the spiral and progresses slowly towardthe centre of the spiral, producing a mosquito-repellent smoke. A typicalmosquito coil can measure around 1 cm in diameter and lasts around !hours. "osquito coils are widely used in Asia, Africa, #outh America andAustralia.

$n%ention

&yrethrum was used for centuries as an insecticide in &ersia and 'urope, andthe mosquito coil was de%eloped around the 1!()s by a *apanese business

man, 'iichiro +eyama. At that time in *apan, people usually mi ed pyrethrumpowder with sawdust and burned it in a bra ier or incense burner to repelmosquitoes. $nitially, +eyama created incense sticks mi ed from starchpowder, dried mandarin orange skin powder, and pyrethrum powder.

owe%er, the bar-shaped mosquito sticks quickly burned up in about /)minutes, too brief for a long repelling action. $n 1!( , his wife 0uki proposedmaking the sticks thicker and longer, and curling them in spirals. $n 1() ,after a series of trials and errors, he nally obtained the desired incenseburning e2ect out of a spiral-shaped mosquito repellent. The methodin%ol%ed cutting from a thick bar of incense to a certain length and manuallywinding it. This method continued to be used until 1( 3, where mass

production was made possible through machine punching, making a farlarger manufacturing scale possible. After the #econd 4orld 4ar, hiscompany, 5ainihon *ochugiku 6o. 7td , set up 8oint-%enture rms in %ariouscountries, such as 6hina and Thailand , to produce products suited to localconditions.

Ingredients

Acti%e ingredients found in mosquito coils may include9

• &yrethrum - a natural, powdered material from a kind ofchrysanthemum plant: performance moderate

• &yrethrins - an e tract of the insecticidal chemicals in pyrethrum

• Allethrin - sometimes d-trans-allethrin, the rst synthetic pyrethroid

• 'sbiothrin - a form of allethrin

http://en.wikipedia.org/wiki/Insect_repellenthttp://en.wikipedia.org/wiki/Incensehttp://en.wikipedia.org/wiki/Pyrethrumhttp://en.wikipedia.org/wiki/Pyrethrumhttp://en.wikipedia.org/wiki/Insecticidehttp://ja.wikipedia.org/wiki/%E5%A4%A7%E6%97%A5%E6%9C%AC%E9%99%A4%E8%99%AB%E8%8F%8Ahttp://en.wikipedia.org/wiki/Chinahttp://en.wikipedia.org/wiki/Thailandhttp://en.wikipedia.org/wiki/Pyrethrumhttp://en.wikipedia.org/wiki/Pyrethrinshttp://en.wikipedia.org/wiki/Allethrinhttp://en.wikipedia.org/wiki/Esbiothrinhttp://en.wikipedia.org/wiki/Incensehttp://en.wikipedia.org/wiki/Pyrethrumhttp://en.wikipedia.org/wiki/Pyrethrumhttp://en.wikipedia.org/wiki/Insecticidehttp://ja.wikipedia.org/wiki/%E5%A4%A7%E6%97%A5%E6%9C%AC%E9%99%A4%E8%99%AB%E8%8F%8Ahttp://en.wikipedia.org/wiki/Chinahttp://en.wikipedia.org/wiki/Thailandhttp://en.wikipedia.org/wiki/Pyrethrumhttp://en.wikipedia.org/wiki/Pyrethrinshttp://en.wikipedia.org/wiki/Allethrinhttp://en.wikipedia.org/wiki/Esbiothrinhttp://en.wikipedia.org/wiki/Insect_repellent

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