## 1 Introduction  
In Southeast Asia, incense sticks are burned to worship ancestors and pray to deities. According to the recent studies in Taiwan and China, smoke from incense combustion in temples contains many particles and gaseous pollutants [1]. [PERSON] _et al_. conducted field investigations of target air pollutants at two of the most famous temples in Hong Kong [2]. The target air pollutants were particulate matters (PM\({}_{2.5}\) and PM\({}_{10}\)), volatile organic compounds (VOCs), carbonyl compounds, carbon monoxide, nitrogen oxides, methane, non-methane hydrocarbons (NMHC), organic carbon, elemental carbon (EC), and inorganic ions (CI\({}^{-}\), NO\({}_{3}\)\({}^{-}\), SO\({}^{4-}\), Na\({}^{+}\), NH\({}_{4}\)\({}^{+}\), and K\({}^{+}\)). The PM was composed of fine particles; namely, average PM\({}_{2.5}\)/PM\({}_{10}\) ratios were approximately 82%. Formaldehyde was the most abundant carbonyl compounds, followed by acetaldehyde. Polycyclic aromatic hydrocarbons (PAHs), in their particulate phase generated from burning incense, were further analyzed by [PERSON] _et al_. using gas chromatography/mass spectrometry (GC/MS) [3]. Tested Taiwanese incenses yield emission factors in the range of 4.19-82.16 mg/g and 1.20-9.50 \(\upmu\)g/g, respectively, for total PM and PAHs. The potential hazard to human health passed by burning incense is an important focus from the viewpoint of indoor air quality. [PERSON] _et al_. [4] investigated the emission characteristics of allergenic aromatic eugenol and its related compounds from the incense powder emitted from burning incense sticks. Experimental results indicate that 870.8-593.7 mg fragrant compounds (methyl isoeigenol was the most prevalent compound) were emitted by combustion one gram of incense. [PERSON] _et al_. [5] showed that temple workers in Thailand are exposed to relatively high levels of benzene (45.90 \(\upmu\)g/m\({}^{3}\)) 1,3-butadiene (11.29 \(\upmu\)g/m\({}^{3}\)) and PAHs (19.56 ng/m\({}^{3}\)). Even mean total polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F) concentrations 72.4-82.2 pg/m\({}^{3}\) were examined at two indoor Taiwanese temples; the PCDD/F were roughly 11 times that at a background location [6]. As incense has various compositions [3], especially the incense manufactured in different countries [7,8], its combustion typically produces different products. [PERSON] _et al_. [3] reported that the atomic hydrogen to carbon (H/C) ratio in incense was the key factor affecting emission PM and PAH emission factors. The maximum emission factor and slowest burning rate were at an H/C ratio of 1.57. [PERSON] _et al_. [7], who compared several incenses used in the United Arab Emirates, found that different raw plant materials in incense sticks, such as essential oils and resins, resulted in hugely different emissions of particles, the sizes of which were 20-300 nm with median count diameters of 65-92 nm. [PERSON] _et al_. [8] also noted that combustion of incenses made in Taiwan and Japan emitted particles with different diameters due to the use of a bamboo stick in Taiwanese incenses and but not Japanese incenses. Households in Taiwan often burn license coils all day. Incense coils, which are composed of fragrance powders, are formed by winding a long, narrow incense strip in a circular pattern (Figure 1). The scent emitted from these coils when burned is generally used as deodorant, for disinfection and for relaxation. Although many studies have characterized the particles and gaseous products emitted from burning license sticks, the products from burning incense coils indoors have largely been ignored. The main by-products of burning incense coils are predictably VOCs. To characterize emissions from burning incense sticks, [PERSON] _et al_. [7] and [PERSON] _et al_. [8] respectively designed stainless steel and glass chambers to that simulated indoor environments and then collected samples from exhaust streams produced by the burning incense sticks.