Incense sticks (or agarbattis as called in India
and adjoining nations) are one of omnipresent essential entity of all religious
rituals in East, both for living as well for dead. If the advertisements are to
be believed, incense provides a soothing pleasant aroma that helps in
concentration, meditation and even has aphrodisiac ability.
Intelligent people don’t believe in advertisement
and neither did the researchers from South China University of Technology and
the China Tobacco Guangdong Industrial Company in China. This group of
researchers for the first time proved that incense smoke is as harmful as
cigarette smoke.
Indoor air pollution affects the health of the
household because of two apparent reasons:
a: Activities like cooking, smoking, and burning
incense happen on daily basis. Moreover, these activities are repeated day
over, so the harmful residues from these activities get concentrated over time.
b: People spend most of their indoors. Thus, they
breathe air which is highly concentrated with the residues of the
flame-dependent activities.
Just like cigarette smoke, epidemiological
investigations have demonstrated that the combustion of incense is correlated
with lung cancer, childhood leukemia and brain tumors. Incense burning being a
part of tradition (and religion) prevented in-depth analysis of its harmful
effects. The raw materials used to make incenses are diverse, but two of the
most common ingredients are agarwood and sandalwood tree resin. The researchers
short-listed two incense types with these two components for their study. The
smoke from a cigarette (3R4F reference cigarette, University of Kentucky) was
measured on a smoking machine, according to ISO 3308:2000. The total
particulate matter and major chemical components of two types of incense smoke
were characterized using an electrical low pressure impactor and gas
chromatography coupled with mass spectrometry. Their genotoxicity and
cytotoxicity were compared with mainstream tobacco smoke using in vitro assays.
Four different incense sticks (sourced from Australia, Indonesia, Malaysia
and southwest China) were experimentally involved in 45 min of incense burning.
The observations/analysis of these experiments are reported as:
Particle size distribution: The aerodynamic diameters of
particulates emitted by these four samples were all below 5 uM. Particles
smaller than 0.1 uM are labeled ultrafine particles, and those between 0.1 and
2.5 uM are termed fine particles. The data obtained from this study clearly
showed that the particulate number and mass measured in incense smoke were
dominated by ultrafine and fine particles (99%) which is likely to cause
adverse health effects such as bronchitis etc.
Chemical composition: The highly volatile compounds common to all
four samples were mostly irritants and hypotoxic. A number of compounds
occurred in all four samples, including monoterpenes, methoxylated phenolics,
two hexose dehydration compounds, as well as other highly volatile compounds. There
also were some hypertoxic compounds detected in one or two samples, for example
ethyl cyanoacetate and 2-butenal.
In vitro mutagenicity: The total particulate matter from four
incense smoke samples was shown to be mutagenic in Ames tests. Incense smoke contains
chemical properties that could potentially change genetic material such as DNA,
and therefore cause mutations.
In vitro cytotoxicity: Genotoxicity to different strains of
certain incense samples was higher than for the reference cigarette sample with
the same dose. The half maximal inhibitory concentration of this cigarette was
much higher than for the four incense samples, indicating that incense smoke
was more cytotoxic against Chinese hamster ovary cells.
Incense smoke was also more cytotoxic and genotoxic than the
cigarette smoke used in the study. This means that incense smoke is potentially
more toxic to a cell, and especially to its genetic contents. Mutagenics,
genotoxins and cytotoxins have all been linked to the development of cancers.
The authors conclude as “Clearly, there needs to be greater
awareness and management of the health risks associated with burning incense in
indoor environments but one should not simply conclude that incense smoke is
more toxic than cigarette smoke. The small sample size, the huge variety of
incense sticks on the market and differences in how it is used compared to
cigarettes must be taken into account.”
The burning of incense might need to come with a health warning.
Article Citation: Zhou, R.; et. al. Higher
cytotoxicity and genotoxicity of burning incense than cigarette. Environmental
Chemistry Letters. 2015. DOI:10.1007/s10311-015-0521-7.
