Hazard assessment of United Arab Emirates (UAE) incense smoke
, Kenneth G. Sexton
, Karin B. Yeatts
Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431, USA
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431, USA
• We performed a hazard assessment of Arabian incense smoke burned indoors.
• We characterized generated pollutants over time, and cell inﬂammatory response.
• Emitted smoke contained proliﬁc particles and government regulated air pollutants.
• Evidence of incense smoke-related cell inﬂammatory response was observed.
• These results suggest a potential health risk from burning Arabian incense indoors.
Received 4 December 2012
Received in revised form 21 March 2013
Accepted 28 March 2013
Available online 4 May 2013
Incense burning inside the home, a common practice in Arabian Gulf countries, has been recognized as a po-
tentially modiﬁable source of indoor air pollution. To better understand potential adverse effects of incense
burning in exposed individuals, we conducted a hazard assessment of incense smoke exposure. The goals
of this study were ﬁrst to characterize the particles and gases emitted from Arabian incense over time
when burned, and secondly to examine in vitro human lung cells responses to incense smoke. Two types
of incense (from the United Arab Emirates) were burned in a specially designed indoor environmental cham-
ber (22 m
) to simulate the smoke concentration in a typical living room and the chamber air was analyzed.
Both particulate (PM) concentrations and sizes were measured, as were gases carbon monoxide (CO), sulfur
), oxides of nitrogen (NO
), formaldehyde (HCHO), and carbonyls. During the burn, peak concen-
trations were recorded for PM (1.42 mg/m
), CO (122 pm), NO
(0.3 ppm), and HCHO (85 ppb) along with
pentanal (71.9 μg/m
), glyoxal (84.8 μg/m
), and several other carbonyls. Particle sizes ranged from 20 to
300 nm with count median diameters ranging from 65 to 92 nm depending on time post burn-out. PM,
CO, and NO
time-weighted averages exceeded current government regulation values and emissions seen
previously from environmental tobacco smoke. Charcoal emissions were the main contributor to both the
high CO and NO
concentrations. A signiﬁcant cell inﬂammatory response was observed in response to
smoke components formed from incense burning. Our hazard evaluation suggests that incense burning con-
tributes to indoor air pollution and could be harmful to human health.
© 2013 Elsevier B.V. All rights reserved.
Burning incense is a popular practice inside residential homes, in
shops, and in places of worship in the United Arab Emirates (UAE),
the Arabian Gulf Peninsula, and other countries around the world
(Fang et al., 2002; Jetter et al., 2002; Yeatts et al., 2012; Yeatts et al.,
2012). Incense is burned weekly in 94% of Emirati households
(Yeatts et al., 2012); it is a cultural practice, to perfume both clothing
and the home, and to remove the odors of ﬁsh or other food smells as-
sociated with indoor cooking.
Indoor air pollution and its sources have become of increasing
concern to due to the limited ventilation rate as compared to out-
doors, and the fact that people spend over 90% of their time indoors
(Klepeis et al., 2001). Indoor air pollution resulting from speciﬁc in-
door activities such as cooking or smoking cigarettes has been charac-
terized (Löfroth et al., 1991); however incense emissions as a type of
indoor air pollutant have not been well characterized. In a low venti-
lation area such as a home, it is hypothesized that smoke emitted
from incense would result in high concentrations of harmful chemical
One of the more common types of incense used in the UAE is Oudh,
comprised of agar wood from the Aquilaria agallocha. These trees devel-
op an aromatic smell as part of a response to fungal infections (Alokail
et al., 2011). Another popular type of incense is Bahkoor, which is de-
rived from sandalwood tree resin and mixed with agarwood, essential
oils, and other substances (Wahab and Mostafa, 2007). These types
Science of the Total Environment 458–460 (2013) 176–186
⁎ Corresponding author. Tel.: +1 512 762 5386.
E-mail address: firstname.lastname@example.org (R. Cohen).
0048-9697/$ – see front matter © 2013 Elsevier B.V. All rights reserved.
Contents lists available at SciVerse ScienceDirect
Science of the Total Environment
journal homepage: www.elsevier.com/locate/scitotenv