MOSQUITO COILS

Hafiz b HassanGS26727

WHAT ARE MOSQUITO COILS?

A mosquito repelling incense Made from pyrethrum powder - natural

insecticide made from the dried flower heads of Chrysanthemum (C. cinerariifolium and C. coccineum)

Shaped into a coil – burning begins from outer end and moves into inner end producing smoke.

Typical coils 15cm from end to end, lasts 8 hours

PYRETHRUM

Actually a mixture of several compounds -pyrethrins , cinerins.

Used to be made by grinding dried chrysanthemum flowers into a powder. Now solvent extraction is used.

In Asia 200 years ago, people discovered that extracts from crushed crysanthemums kill insects.

Used as ‘lice powder’ (famous usage by Napoleon and his forces)

Relatively low toxicity - breaks down quickly,

Generally has low environmental impact 

HISTORY

Mosquito coils were invented by Eiichiro Ueyama. At first, he brought the pyrethrum seeds from America

to be planted and milled as a flea repellant (1885) The flea repellant won Merit Prize in the 3rd National

Industrial Exhibition in Tokyo (1890) After meeting an incense seller, he wanted to further

simplify the application of the powder – creating ‘candles’

Original production method mix starch powder and dried mandarin orange skin

powder + pyrethrum powder, knead it thoroughly, put it into a wooden mortar, extrude it, then cut it into the form of stick incense (candle)

However, the starch-pyrethrum ‘candle’ mix burns too quickly (40 minutes).

Needs 2-3 candles for maximum effect Wife, Yuki, proposed elongating and

thickening the candles and winding it into a spiral (1895).

By 1920, a working prototype is developed (after trial and error)

1957 – mass production, machine manufactured

HOW THEY ARE MADE

Ingredients : Starch (potato starch, corn starch, rice or wheat

starch) Coconut flour mix Sawdust Dye (for colour) Burning aids (sodium and potassium nitrate,

sodium benzoate etc) 0.5% mass of insecticide

Pyrethrum/pyrethroid Allethrin, bioallethrin

HOW THEY ARE MADE

Process Dispersing from 16- 26% by weight on a dry basis potato starch in

water having a temperature of from 40- 60° C.; Gelling the dispersed starch by adding sufficient water having a

temperature of from 80- 95° C. to the starch-water dispersion to raise the temperature of the resulting mixture to above the gelling point of the starch;

Adding from 72- 83% by weight on a dry basis of a carrier, from 0.5--3% by weight on a dry basis of an insecticide and from 0- 2% by weight on a dry basis of a burning aid to the gelled starch-water mixture;

Forming thin sheets from the carrier starch-water mixture; Forming mosquito coils from the thin sheets; Drying the formed mosquito coils with the provision that the ratio

of dry ingredients to water is within the range of from 1:1- 1:2.5.

ADVANTAGES

Provides as much as 80% protection Long term (8-10 hours) protection No flames Need no special equipment to be used Portable Chemically inert (unless ingested)

DISADVANTAGES

The odor and smoke – asthmatics threat Although no flame, but sparks can be

emitted – fire hazard Releases VOC (formaldehydes), PAHs and

particulate matter – hazardous to health If used in badly ventilated area – indoor

pollution and discomfort One coil – 75 to 150 times more smoke

than cigarettes.

REFERENCES

Osaka Foundation for Trade & Industry (2004). Eiichiro Ueyama , Developing and promoting insecticide together with pyrethrum. Retrieved on 22 September 2010, from http://www.ibo.or.jp/en/2004_4/index.html

Sumitomi Chemical Company, Limited (1973). Fumigant Insecticidal Mixtures Of D-chrysanthemates. Retrieved on 22 September 2010, from http://www.freepatentsonline.com/3723615.html

Weili, L., Junfeng, Z., Hashim, J.H., Jalaludin, J., Hashim, Z., Goldstein, B. D. (2003). Mosquito Coil Emissions and Health Implications. Environmental Health Perspectives 111 (12): 1454–1460

DAINIHON JOCHUGIKU Co.,Ltd. History of Kincho Corp. Retrieved on 27 September 2010 from http://www.kincho.co.jp/kaisha/english/ayumi/ayumi.html

Histria Aromatica, 2005. The History of Pyrethrum. Retrieved in 27 September 2010 from http://www.aromatica.hr/eng/page.asp?id=buhac&sub=buhac3