The burning of incense produces toxic and harmful gases and particulate matters, posing a tremendous threat to both human health and the atmospheric environment. As a consequence, online in situ detection, classification, and traceability of burnt incense are of vital importance. In this paper, taking ambergris, musk, and Tibetan incense as examples, laser-induced breakdown spectroscopy (LIBS) is applied to the online detection of smoke and ash from the burning of three common types of incenses. It is found that metallic elements such as K, Mg, and Ca are present in the smoke. In contrast, more complex metallic elements, such as Fe, Al, Mn, Sr, etc., are present in the incense ash. By comparing the smoke and ash spectra of three different incenses, the feature spectra with large differences are selected, and the data are dimensionality reduced using the principal component analysis. Combined with error back propagation training artificial neural networks, the classification and traceability models of the smoke and ash from different incenses are performed, and the final recognition accuracies are 93.24% and 96.33%, respectively. All the results indicate that the combination of LIBS and machine learning has good application prospects for detecting and online tracing different incense smoke and ash and is also beneficial for human health and the natural environment.

1.
S. C.
Chang
,
Y. C.
Cheng
, and
X. H.
Zhang
, “
Effects of moisture content on explosion characteristics of incense dust in incense factory
,”
J. Therm. Anal. Calorim.
147
,
2885
2892
(
2022
).
2.
A. H.
Bu-Olayan
and
B. V.
Thomas
, “
Exposition of respiratory ailments from trace metals concentrations in incenses
,”
Sci. Rep.
11
,
10210
(
2021
).
3.
W. Y.
Kao
,
C. Y.
Hsiang
, and
S. C.
Ho
, “
Novel serotonin-boosting effect of incense smoke from kynam agarwood in mice: The involvement of multiple neuroactive pathways
,”
J. Ethnopharmacol.
275
,
114069
(
2021
).
4.
I. C.
Santos Ines
,
Smuts
Jonathan
, and
Kevin A.
Schug
, “
Rapid profiling and authentication of vanilla extracts using gas chromatography-vacuum ultraviolet spectroscopy
,”
Food Anal. Methods
10
,
4068
4078
(
2017
).
5.
J.
Li
,
H. M.
Xu
, and
D.
Song
, “
Emission characteristics and assessment of potential health risks on PM2.5-bound organics from incense burning
,”
Atmos. Pollut. Res.
13
,
101326
(
2022
).
6.
R.
Zhou
,
Q.
An
, and
X. W.
Pan
, “
Higher cytotoxicity and genotoxicity of burning incense than cigarette
,”
Environ. Chem. Lett.
13
,
465
471
(
2015
).
7.
X. Y.
Niu
,
T.
Jones
, and
K.
BeruBe
, “
The oxidative capacity of indoor source combustion derived particulate matter and resulting respiratory toxicity
,”
Sci. Total Environ.
767
,
144391
(
2021
).
8.
K. C.
Chen
,
S. W.
Tsai
, and
R. H.
Shie
, “
Indoor air pollution increases the risk of lung cancer
,”
Int. J. Environ. Res. Public Health
19
,
1164
(
2022
).
9.
N.
Yamamoto
,
K.
Kan-o
, and
M.
Tatsuta
, “
Incense smoke-induced oxidative stress disrupts tight junctions and bronchial epithelial barrier integrity and induces airway hyperresponsiveness in mouse lungs
,”
Sci. Rep.
11
,
7222
(
2021
).
10.
Thamir M.
Al-khlaiwi
and
Sultan
Ayoub
, “
Incense burning indoor pollution: Impact on the prevalence of prediabetes and type-2 diabetes mellitus
,”
Pak. J. Med. Sci.
38
,
1852
1856
(
2022
).
11.
Z. L.
Zhang
,
L. X.
Tan
, and
A.
Huss
, “
Household incense burning and children's respiratory health: A cohort study in Hong Kong
,”
Pediatr. Pulmonol.
54
,
399
404
(
2019
).
12.
Z. H.
Yang
,
J.
Ren
, and
M. Y.
Du
, “
Enhanced laser-induced breakdown spectroscopy for heavy metal detection in agriculture: A review
,”
Sensors
22
,
5679
(
2022
).
13.
R. W.
Liu
,
K.
Rong
, and
Z. Z.
Wang
, “
Sample temperature effect on steel measurement using SP-LIBS and collinear long-short DP-LIBS
,”
ISIJ Int.
60
,
1724
1731
(
2020
).
14.
Maria
Markiewicz-Keszycka
,
Xavier
Cama-Moncunill
, and
Maria P.
Casado-Gavalda
, “
Laser-induced breakdown spectroscopy (LIBS) for food analysis: A review
,”
Trends Food Sci. Technol.
65
,
80
93
(
2017
).
15.
Y.
Zhao
,
Q. Q.
Wang
, and
X. T.
Cui
, “
Laser-induced breakdown spectroscopy for the discrimination of explosives based on the relief algorithm and support vector machines
,”
Front. Phys.
9
,
675135
(
2021
).
16.
X.
Lu
,
Y. Z.
Liu
, and
J. P.
Yao
, “
Online detection and source tracing of VOCs in the air
,”
Opt. Laser Technol.
149
,
107826
(
2022
).
17.
Q. H.
Zhang
,
Y.
Chen
, and
Y. Z.
Liu
, “
Study on the online detection of atmospheric sulfur via laser-induced breakdown spectroscopy
,”
J. Anal. At. Spectrom.
36
,
1028
1033
(
2021
).
18.
Q. H.
Zhang
,
Y. Z.
Liu
, and
W. Y.
Yin
, “
The online detection of carbon isotopes by laser-induced breakdown spectroscopy
,”
J. Anal. At. Spectrom.
35
,
341
346
(
2020
).
19.
J.
Tang
,
Z.
Li
,
M.
Xie
,
Y.
Zhang
,
W.
Long
, and
S.
Long
, “
Optical fiber bio-sensor for phospholipase using liquid crystal
,”
Biosens. Bioelectron.
170
,
112547
(
2020
).
20.
C. M.
Du
,
X. Y.
Liu
, and
W.
Miao
, “
Investigation on laser-induced breakdown spectroscopy of MgCL2 solution
,”
OPTIK
187
,
98
102
(
2019
).
21.
D.
Paules
,
S.
Hamida
, and
R. J.
Lasheras
, “
Characterization of natural and treated diatomite by laser-induced breakdown spectroscopy (LIBS)
,”
Microchem. J.
137
,
1
7
(
2018
).
22.
L. B.
Guo
,
D.
Zhang
, and
L. X.
Sun
, “
Development in the application of laser-induced breakdown spectroscopy in recent years: A review
,”
Front. Phys.
16
,
22500
(
2021
).
23.
J. X.
Qi
,
G. Z.
Jiang
, and
G. F.
Li
, “
Surface EMG hand gesture recognition system based on PCA and GRNN
,”
Neural Comput. Appl.
32
,
6343
6351
(
2021
).
24.
X.
Lu
,
Y. Z.
Liu
, and
Y. B.
Zhou
, “
Real-time in situ source tracing of human exhalation and different burning smoke indoors
,”
Spectrochim. Acta Part B
170
,
105901
(
2020
).
25.
X. Y.
Zhang
,
Z. M.
Sun
, and
Z. Y.
Zhou
, “
Analysis and dynamic monitoring of indoor Air quality based on laser-induced breakdown spectroscopy and machine learning
,”
Chemosensors
10
,
259
(
2022
).
26.
E. L.
Wan
,
Y. Z.
Liu
, and
Z. M.
Sun
, “
Online in situ detection of local air conditions in hazardous operation scenarios
,”
Chemosphere
298
,
134219
(
2022
).
27.
Z.
Xiong
,
Z. Q.
Hao
, and
X. Y.
Li
, “
Investigation on the reduction of self-absorption effects in quantitative analysis using fiber laser ablation laser-induced breakdown spectroscopy
,”
J. Anal. At. Spectrom.
34
,
1606
1610
(
2019
).
28.
National Institute of Standards and Technology, see http://webbook.nist.gov/chemistry/form-ser/ for “NIST Chemistry WebBook, SRD69.”
29.
Y. F.
Qu
,
H.
Ji
, and
F.
Oudray
, “
Online composition detection and cluster analysis of Tibetan incense
,”
Optik
241
,
166999
(
2021
).
30.
Q. H.
Zhang
,
Y. Z.
Liu
, and
W. Y.
Yin
, “
The in situ detection of smoking in public area by laser-induced breakdown spectroscopy
,”
Chemosphere
242
,
125184
(
2020
).
31.
S.
Liwicki
,
G.
Tzimiropoulos
, and
S.
Zafeiriou
, “
Euler principal component analysis
,”
Int. J. Comput. Vis.
101
,
498
518
(
2013
).
32.
J. R.
Beattie
and
F. W. L.
Esmonde-White
, “
Exploration of principal component analysis: Deriving principal component analysis visually using spectra
,”
Appl. Spectrosc.
75
,
361
375
(
2021
).
33.
V. K.
Yadav
,
K. K.
Yadav
, and
J.
Alam
, “
Transformation of hazardous sacred incense sticks ash waste into less toxic product by sequential approach prior to their disposal into the water bodies
,”
Environ. Sci. Pollut. Res.
(published online 2021).
34.
H. B.
Yang
,
H. Y.
Bu
, and
M. N.
Li
, “
Prediction of flow stress of annealed 7075 Al alloy in hot deformation using strain-compensated Arrhenius and neural network models
,”
Materials
14
,
5986
(
2021
).
You do not currently have access to this content.