This article makes the following assertion.
Smoke emitted from one mosquito repellant coil is equivalent to those of 100 cigarettes, thus causing harm to a large number of people in India...
Is there any truth in the claims made by the above article ?
Yes, kind of.
The researcher quoted in that page is Sandeep Salvi, director of the Chest Research Foundation.
He was one of the authors of a paper that was presented at the National Pulmonary Congress, 2004, Ahmedabad. (Note: I assume that means it was not peer-reviewed.)
Burning mosquito coil (MC) releases various aromatic compounds like benzo pyrenes, benzo-fluoroethane and particulate matters. These chemicals have the potential to produce harmful effects on airways as demonstrated by histopathological changes in the airways of various animal models. It has been estimated that burning one MC over 8 hours produces particulate matter smoke (as measured as PM2.5) equivalent to around 100 cigarettes.
Okay, so there is an estimate that someone has made. Unfortunately, the page I have found has no references, so I can't be sure who made the estimate, but let me come back to this.
So, anyway, 12 asthmatics and 12 healthy subjects were exposed to an hour of mosquito coils (twice each) and various lung functions were measured to see if there was any short-term effect:
There conclusion was... not significant.
One-hour exposure to mosquito coil did not cause decrements in lung function parameters. There was [an apparent effect] but this did not reach statistical significance.
They go on to say they will be trying with larger samples and longer exposure, but eight years later, there doesn't seem to be any results published.
So, there's no significant evidence there of short-term effect on humans.
The most likely source of the estimate would appear to be:
In their paper, they first talk about the known toxic effects of mosquito coils, including "long-term exposure to mosquito coil smoke can induce asthma and persistent wheeze in children", as well as various symptoms in rat models.
They went on study the smoke of six different brands of mosquito coils from two different countries (Malaysia and China). They looked for troublesome components, such as particulate matter < 2.5 μm in diameter (PM2.5), polycyclic aromatic hydrocarbons, aldehydes, and ketones in "realistic room conditions".
They generally found the levels of pollutant to be concerning, and the Malaysian brands were generally more polluting.
The findings from the present study suggest that exposure to the smoke of mosquito coils similar to the tested ones can pose significant acute and chronic health risks.
They compared some of the elements to cigarette smoke:
For example, burning one mosquito coil would release the same amount of PM2.5 mass as burning 75–137 cigarettes. The emission of formaldehyde from burning one coil can be as high as that released from burning 51 cigarettes.
Without trying to diminish the risks, it is important to note that this is saying that some of the components (PM2.5 and formaldehyde) in the mosquito coil smoke (inhaled over an 8 hour period) were as bad as some of the components in a large number of cigarettes. There may be other compounds in cigarette smoke that also cause damage which are not found in mosquito coils.
