Prolonged exposure to mosquito coil smoke can make you sick, says new study

Using mosquito coils is a common phenomenon in Indian homes and offices. However, prolonged exposure to smoke generated by the repellants could have an adverse impact on human health, a recent study has found. The study which examined common Indian brands found that the burning of mosquito coils and cigarettes in an indoor environment emit considerable polluting particles that could lead to illnesses.

Published in the journal SN Applied Sciences in April, the study ruled out chances of cancer being caused by these coils and cigarettes and noted that further investigation in actual environments was needed to understand the cancer link more deeply.

The study aimed to characterise the emissions of indoor air pollutants from different types of mosquito coils and cigarettes. It used a closed environmental chamber, to compare air pollutant emissions and quantified the emissions of particulate matter – PM0.25, PM1.0, PM2.5 and PM10 – and metals.

Mosquito coils and cigarettes were monitored in three different phases: pre-burning, during burning and post-burning. The samples collected were analysed for heavy metals like aluminium, copper, zinc, cadmium, chromium, manganese, nickel, lead, vanadium, selenium and scandium.

According to the study, both types of samples had a higher concentration of aluminium, copper, zinc and manganese than cadmium, valium and selenium.

“Smoke comes out of both mosquito coils as well as cigarettes when burnt,” said Ajay Taneja of the chemistry department of Agra-based BR Ambedkar University and the lead author of the study. “But the smokes are very complex [and] contain more than 4,000 chemicals. We have analysed only the metals in them and their impact. We concluded that on a long term if there is continuous use of such materials it is going to have some effects on health.”

Not cancerous

However, Taneja explained to Mongabay that though these emissions could lead to respiratory issues, “there is no way of predicting after how long they will start the impact” as they would vary with every person.

The study stressed that calculations were made to explore expected cancer and non-cancer risks, using published toxicity potentials for three metals – chromium, lead and nickel – and found that cancer risk was within safe limits. On a query that whether popularly used liquid-electric based mosquito repellents could be a solution, Taneja rejected the idea.

“No, they are not a solution,” Taneja added. “It is because their use would also result in the release of some kind of organic chemicals. What will be the long term [effect] of those chemicals is something still unknown?”

According to the recent India State Level Disease Burden Initiative analysis published in The Lancet journal in December 2018, of the total deaths in India in 2017, 1.24 million deaths – equivalent to 12.5% of total mortalities – could be attributed to air pollution.

Air pollution has emerged as a significant issue in India over the past few years which finally resulted in the central government releasing a national clean air programme to tackle the crisis of severely polluted air across the major areas of the country. Among other things, the programme started by the Indian government’s environment ministry also focuses on controlling indoor air pollution.

The study also noted that apprehension regarding the concept of indoor air quality has increased in recent years due to the “recognition of different pollutants originating from diverse indoor and outdoor sources”.

It stressed that illnesses related to respiratory and cardiovascular issues, even potential carcinogenicity, is also a direct consequence of long-term exposure to the contaminants residing in indoor air. “The smoke emitted from their combustion releases particulate matter and the combustion leads to the production of a large amount of smoke, which when inhaled poses a wider health hazard,” the study added.

Explaining the impact of fine particulate matter, Ajay Taneja said that they can cause problems like respiratory diseases, rashes on skin and allergies. However, Taneja said, this study does not indicate any risk of cancer right now.

Further study needed

The study noted that heavy metals in the environment are of great concern because of their toxicity.

“Smoking of cigarettes and using mosquito coils to repel and kill vectors are critical,” said the study. “However, their improper use by consumers may lead to other health problems that should not be ignored. Overall, the results of this study reveal that aluminium, chromium and ten were found higher in mosquito coils, whereas copper, zinc, manganese, nickel and lead were higher in cigarette samples. Particular elements may be attributed to the raw material used for manufacturing both [mosquito coil and cigarette].”

The maximum individual risk of health problem was found to be associated with chromium and minimum with lead in mosquito coil samples and cigarette samples though it was below the threshold levels.

Admitting that this analysis was a short-term study as the time of exposure was very limited and the concentration of metals was below the limits, the study said, “it is believed that if the exposure duration is larger, then the concentration of metals would increase”. It further said that a more in-depth investigation should be conducted in actual furnished rooms in a real apartment to evaluate the effects of smoke generated by smoking in an actual residential environment.

Agra-based paediatric surgeon Dr Sanjay Kulshreshtha, who has been fighting several cases in the National Green Tribunal and the Supreme Court, seeking implementation of strict anti-pollution measures, said indoor air pollution is a serious issue and would result in serious impacts on those living in places where air ventilation is not up to the mark.

“The authorities need to focus on all sources of indoor air pollution and need to ascertain the kind of damage they can cause,” Kulshreshtha told Mongabay.

This article first appeared on Mongabay.