Characterization of polycyclic aromatic hydrocarbon emissions in the particulate phase from burning incenses with various atomic hydrogen/carbon ratios

Particulate organic emissions from incense-burning smoke: Chemical compositions and emission characteristics

Incense burning is a common practice in Asian cultures, releasing hazardous particulate organics. Inhaling incense smoke can result in adverse health effects, yet the molecular compositions of incense-burning organics have not been well investigated due to the lack of measurement of intermediate-volatility and semi-volatile organic compounds (I/SVOCs). To elucidate the detailed emission profile of incense-burning particles, we conducted a non-target measurement of organics emitted from incense combustion. Quartz filters were utilized to trap particles, and organics were analyzed by a comprehensive two-dimensional gas chromatography-mass spectrometer (GC × GC-MS) coupled with a thermal desorption system (TDS). To deal with the complex data obtained by GC × GC-MS, homologs are identified mainly by the combination of selected ion chromatograms (SICs) and retention indexes. SICs of 58, 60, 74, 91, and 97 were utilized to identify 2-ketones, acids, fatty acid methyl esters, fatty acid phenylmethyl esters, and alcohols, respectively. Phenolic compounds contribute the most to emission factors (EFs) among all chemical classes, taking up 24.5 % ± 6.5 % of the total EF (96.1 ± 43.1 μg g-1). These compounds are largely derived from the thermal degradation of lignin. Biomarkers like sugars (mainly levoglucosan), hopanes, and sterols are extensively detected in incense combustion fumes. Incense materials play a more important role in shaping emission profiles than incense forms. Our study provides a detailed emission profile of particulate organics emitted from incense burning across the full-volatility range, which can be used in the health risk assessments. The data processing procedure in this work could also benefit those with less experience in non-target analysis, especially GC × GC-MS data processing.

Exposure to incense burning, biomarkers, and the physical health of temple workers in Taiwan

Incense burning releases heavy particulate matter (PM) and nitrogen dioxide (NO2), known to have adverse effects on human health. Long-term exposure to PM and NO2 increases inflammatory cytokine levels and can induce respiratory diseases. This study examined the association between incense burning exposure and the health status, especially inflammatory biomarkers, of temple workers and volunteers in Taiwan. The longitudinal observational study compared adult temple workers and volunteers, with long-term incense burning exposure, to residents from outpatient clinics in the Chiayi area. Forced expiratory volume in 1 s (FEV1) and serum and exhaled breath condensate (EBC) cytokines were assessed. Nonparametric Mann-Whitney U tests were used to compare cytokine levels of the exposure and control groups during the cold and hot weather seasons. FEV1 was significantly more diminished in the exposed group than in the control group during the cold season. Exposure status was associated with greater hot-cold seasonal differences in serum interleukins (IL)-1β (regression coefficient (B) = 6.6, 95% confidence interval (CI) = 5.0 to 8.3, p < .001), IL17-A (B = 2.4, 95% CI = 0.3 to 4.5, p = .03), and plasminogen activator inhibitor [PAI]-1 (B = 5.4, 95% CI = 1.5 to 9.3, p = .009). After adjusting for confounders, the groups' serum levels of IL-1β, IL-17A, and PAI-1 significantly differed. EBC cytokines did not show significant differences. Elevated levels of IL-1β, IL17-A, and PAI-1 have been associated with various autoinflammatory syndromes and diseases. Given the cultural significance of incense burning, culturally sensitive interventions, including education, policy development, and program implementation, are crucial to protect individuals' health, especially temple workers, from the adverse effects of exposure, addressing the manufacture, importation, and sale of incense.

Volatilization behavior of polycyclic aromatic hydrocarbons from the oil-based residues of shale drill cuttings

Shale gas, an emerging oil-bearing and pillar industry at home and abroad, has a very large impact on economic development and industry, but the resulting emerging pollutants pose a serious threat to the environment. Drilling cuttings, the primary byproduct of the exploration and mining of shale gas, are potentially hazardous types of waste that seriously deplete land resources and pose environmental safety problems. In this paper, a long-term static volatilization experiment was conducted to study the volatilization of polycyclic aromatic hydrocarbons (PAHs) in the oil-based residue of shale gas drill cuttings. Furthermore, the effects of some relevant environmental factors controlling the volatilization behavior were evaluated, including different particle sizes, temperatures and illuminances. The results showed that (1) the volatilization concentrations of PAHs gradually increased with prolonged volatilization time. PAHs with smaller ring numbers were present at the highest concentrations among the detected PAHs, and they were more readily volatilized and could be detected earlier. (2) The C-history method was found to significantly describe the kinetic process of the volatilization of PAHs. (3) Different environmental factors had different effects on the volatilization of PAHs. We found that increasing the temperature and illuminance and decreasing the particle size increased volatility. Through canonical correspondence analysis, PAHs volatilization was found to be a complex process, so volatilization tests under simulated environmental conditions are of scientific and environmental interest.

Adolescent lung function associated with incense burning and other environmental exposures at home

Incense burning is a popular cultural and religious practice, but whether exposure to incense smoke has effects on lung function is unclear. We investigated association between lung function and incense burning exposure and other household exposures in adolescents who participated in a mass asthma-screening program. Information on asthmatic status and associated factors was obtained from parent-completed questionnaires and student-completed video questionnaires. Approximately 10% of students received lung function examinations. Valid lung function data of 5010 students aged 14-16 years in northern Taiwan were analyzed. Forced vital capacity (FVC) and forced expiratory flow in 1 second (FEV₁ ) were compared by incense burning status and other types of exposures for adolescents. Overall, 70.6% of students were exposed to incense smoke at home. The mean FVC and FEV₁ measures were lower among adolescents with daily exposure to incense burning than those without such exposure (P<.05). Sharing bedroom was also associated with decreased FVC and FEV₁ . After controlling for confounding factors, multivariable linear regression analysis with generalized estimation equation showed that FVC was negatively associated with daily exposure to incense burning, sharing a bedroom, and living in a house adjacent to a traffic road. Such associations were also observed in FEV₁ . Daily exposure to incense burning is associated with impaired adolescent lung function.

Characterization of particulate-phase polycyclic aromatic hydrocarbons emitted from incense burning and their bioreactivity in RAW264.7 macrophage

This study investigated the effects of particle-bound polycyclic aromatic hydrocarbons (PAHs) produced from burning three incense types on and their bioreactivity in the RAW 264.7 murine macrophage cell line. Gas chromatography/mass spectrometry was used to determine the levels of 16 identified PAHs. Macrophages were exposed to incense particle extracts at concentrations of 0, 3.125, 6.25, 12.5, 25, 50, and 100 μg/mL for 24 h. After exposure, cell viability and nitric oxide (NO) and inflammatory mediator [tumor necrosis factor (TNF)-α] production of the cells were examined. The mean atomic hydrogen (H) to carbon (C) ratios in the environmentally friendly, binchotan charcoal, and lao shan incenses were 0.69, 1.13, and 1.71, respectively. PAH and total toxic equivalent (TEQ) mass fraction in the incenses ranged from 137.84 to 231.00 and 6.73-26.30 pg/μg, respectively. The exposure of RAW 264.7 macrophages to incense particles significantly increased TNF-α and NO production and reduced cell viability. The cells treated with particles collected from smoldering the environmentally friendly incense produced more NO and TNF-α compared to other incenses. Additionally, the TEQ of fluoranthene (FL), pyrene (Pyr), benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (INP), dibenz[a,h]anthracene (DBA), and benzo[g,h,i]perylene [B(ghi)P] had a significant correlation (R² = 0.64-0.98, P < 0.05) with NO and TNF-α production. The current findings indicate that incense particle-bound PAHs are biologically active and that burning an incense with a lower H/C ratio caused higher bioreactivity. The stimulatory effect of PAH-containing particles on molecular mechanisms of inflammation are critical for future study.

Analysis of Pesticides and Toxic Heavy Metals Contained in Mosquito Coils

In this study, 10 mosquito coils manufactured in China were obtained in Suriname, South America, where they are used extensively. The coils were analyzed for organics (allethrin, permethrin, and butylated hydroxytoluene) and heavy metals (Cr, Co, As, Cd, and Pb) by GC-MS and ICP-MS, respectively. Allethrin was the only target organic compound detected in all mosquito coils with concentrations ranging from ~1900 to ~4500 µg/g. The concentrations of heavy metals varied as follows (in µg/g): Cr: 2.9-9.4, Co: 0.1-1.2, Cu: 0.7-16.1, Se: 0.10-0.4, Ni: 2.1-5.8, As: 0.10-2.2, Cd: 0.10-0.2, and Pb: 1.1-3.6.

Binary Mixtures of Polycyclic Aromatic Hydrocarbons Display Nonadditive Mixture Interactions in an In Vitro Liver Cell Model

Polycyclic aromatic hydrocarbons (PAHs) have been labeled contaminants of concern due to their carcinogenic potential, insufficient toxicological data, environmental ubiquity, and inconsistencies in the composition of environmental mixtures. The Environmental Protection Agency is reevaluating current methods for assessing the toxicity of PAHs, including the assumption of toxic additivity in mixtures. This study was aimed at testing mixture interactions through in vitro cell culture experimentation, and modeling the toxicity using quantitative structure-activity relationships (QSAR). Clone-9 rat liver cells were used to analyze cellular proliferation, viability, and genotoxicity of 15 PAHs in single doses and binary mixtures. Tests revealed that many mixtures have nonadditive toxicity, but display varying mixture effects depending on the mixture composition. Many mixtures displayed antagonism, similar to other published studies. QSARs were then developed using the genetic function approximation algorithm to predict toxic activity both in single PAH congeners and in binary mixtures. Effective concentrations inhibiting 50% of the cell populations were modeled, with R(2) = 0.90, 0.99, and 0.84, respectively. The QSAR mixture algorithms were then adjusted to account for the observed mixture interactions as well as the mixture composition (ratios) to assess the feasibility of QSARs for mixtures. Based on these results, toxic addition is improbable and therefore environmental PAH mixtures are likely to see nonadditive responses when complex interactions occur between components. Furthermore, QSAR may be a useful tool to help bridge these data gaps surrounding the assessment of human health risks that are associated with PAH exposures.

Measurements of VOC/SVOC emission factors from burning incenses in an environmental test chamber: influence of temperature, relative humidity, and air exchange rate

This study investigates the influence of three environmental indoor parameters (i.e., temperature, relative humidity, and air exchange rate) on the emission of 13 volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) during incense burning. Experiments have been carried out using an environmental test chamber. Statistical results from a classical two-level full factorial design highlight the predominant effect of ventilation on emission factors. The higher the ventilation, the higher the emission factor. Moreover, thanks to these results, an estimation of the concentration range for the compounds under study can be calculated and allows a quick look of indoor pollution induced by incense combustion. Carcinogenic substances (i.e., benzene, benzo(a)pyrene, and formaldehyde) produced from the incense combustion would be predicted in typical living indoors conditions to reach instantaneous concentration levels close to or higher than air quality exposure threshold values.

Characterization of polycyclic aromatic hydrocarbon emissions in the particulate and gas phase from smoldering mosquito coils containing various atomic hydrogen/carbon ratios

The polycyclic aromatic hydrocarbon emissions in particulate and gas phases generated from smoldering mosquito coils containing various atomic H/C ratios were examined. Five types of mosquito coils were burned in a test chamber with a total airflow rate of 8.0 L/min at a constant relative humidity and temperature. The concentrations of individual PAHs were determined using the GC/MS technique. Among the used mosquito coils, the atomic H/C ratio ranged from 1.23 to 1.57, yielding total mass, gaseous, and particulate PAH emission factors of 28.17-78.72 mg/g, 26,139.80-35,932.98 and 5735.22-13,431.51 ng/g, respectively. The various partitions of PAHs in the gaseous and particulate phases were in the ranges, 70.26-83.70% and 16.30-29.74% for the utilized mosquito coils. The carcinogenic potency of PAH emissions in the particulate phase (203.82-797.76 ng/g) was approximately 6.92-25.08 times higher than that of the gaseous phase (26.27-36.07 ng/g). Based on the analyses of PAH emissions, mosquito coils containing the lowest H/C ratio, a low oxygen level, and additional additives (i.e., CaCO3) are recommended for minimizing the production of total PAH emission factors and carcinogenic potency.