Rates of polycyclic aromatic hydrocarbon emissions from incense

Characterization of unsubstituted and methylated polycyclic aromatic hydrocarbons in settled dust: Combination of instrumental analysis and in vitro reporter gene assays and implications for cancer risk assessment

Concentrations of 34 unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) and AhR-mediated activities in settled dust samples were determined by a combination of gas chromatography-mass spectrometry and an in vitro reporter gene assay (PAH-CALUX). The levels of Σ34PAHs and bioassay-derived benzo[a]pyrene equivalents (CALUX BaP-EQs) were significantly higher in workplace dust from informal end-of-life vehicle dismantling workshops than in common house dust and road dust. In all the samples, the theoretical BaP-EQs of PAHs (calculated using PAH-CALUX relative potencies) accounted for 28 ± 19% of the CALUX BaP-EQs, suggesting significant contribution of aryl hydrocarbon receptor (AhR) agonists and/or mixture effects. Interestingly, the bioassay-derived BaP-EQs in these samples were significantly correlated with not only unsubstituted PAHs with known carcinogenic potencies but also many Me-PAHs, which should be included in future monitoring and toxicity tests. The bioassay responses of many sample extracts were substantially reduced but not suppressed with sulfuric acid treatment, indicating contribution of persistent AhR agonists. Cancer risk assessment based on the CALUX BaP-EQs has revealed unacceptable level of risk in many cases. The application of bioassay-derived BaP-EQs may reduce underestimation in environmental management and risk evaluation regarding PAHs and their derivatives (notably Me-PAHs), suggesting a consideration of using in vitro toxic activity instead of conventional chemical-specific approach in such assessment practices.

Indoor inhalation intake fractions of fine particulate matter: review of influencing factors

Exposure to fine particulate matter (PM_2.5 ) is a major contributor to the global human disease burden. The indoor environment is of particular importance when considering the health effects associated with PM_2.5 exposures because people spend the majority of their time indoors and PM_2.5 exposures per unit mass emitted indoors are two to three orders of magnitude larger than exposures to outdoor emissions. Variability in indoor PM_2.5 intake fraction (iF_in,total ), which is defined as the integrated cumulative intake of PM_2.5 per unit of emission, is driven by a combination of building-specific, human-specific, and pollutant-specific factors. Due to a limited availability of data characterizing these factors, however, indoor emissions and intake of PM_2.5 are not commonly considered when evaluating the environmental performance of product life cycles. With the aim of addressing this barrier, a literature review was conducted and data characterizing factors influencing iF_in,total were compiled. In addition to providing data for the calculation of iF_in,total in various indoor environments and for a range of geographic regions, this paper discusses remaining limitations to the incorporation of PM_2.5 -derived health impacts into life cycle assessments and makes recommendations regarding future research.

Emission characteristics of air pollutants from incense and candle burning in indoor atmospheres

Volatile organic compounds (VOCs) and particles emitted by incense sticks and candles combustion in an experimental room have been monitored on-line and continuously with a high time resolution using a state-of-the-art high sensitivity-proton transfer reaction-mass spectrometer (HS-PTR-MS) and a condensation particle counter (CPC), respectively. The VOC concentration-time profiles, i.e., an increase up to a maximum concentration immediately after the burning period followed by a decrease which returns to the initial concentration levels, were strongly influenced by the ventilation and surface interactions. The obtained kinetic data set allows establishing a qualitative correlation between the elimination rate constants of VOCs and their physicochemical properties such as vapor pressure and molecular weight. The emission of particles increased dramatically during the combustion, up to 9.1(±0.2) × 10(4) and 22.0(±0.2) × 10(4) part cm(-3) for incenses and candles, respectively. The performed kinetic measurements highlight the temporal evolution of the exposure level and reveal the importance of ventilation and deposition to remove the particles in a few hours in indoor environments.

Incense use and respiratory tract carcinomas: a prospective cohort study

BACKGROUND

Incense use is an integral part of daily life in large parts of Asia. The burning of incense is a powerful producer of particulate matter and the smoke contains a multitude of well-characterized carcinogens. However, to the authors' knowledge, no convincing association has been reported between exposure to incense smoke and the development of cancer. Therefore, the relation between incense use and the risk of respiratory tract carcinomas was analyzed in a prospective cohort study.

METHODS

Between 1993 and 1998, a population-based cohort of 61,320 Singapore Chinese who were free of cancer and ages 45 to 74 years completed a comprehensive interview regarding living conditions and dietary and lifestyle factors. Through linkage to population-based registries, the cohort was followed through 2005 and cancer occurrence determined. The relative risk for these cancers associated with incense use was estimated using a Cox proportional hazards model.

RESULTS

A total of 325 upper respiratory tract (UPT) carcinomas and 821 lung carcinomas were observed during follow-up. Incense use was associated with a significantly increased risk of UPT carcinomas other than nasopharyngeal, whereas no overall effect was observed on lung cancer. The duration and intensity of incense use were associated with an increased risk of squamous cell carcinomas in the entire respiratory tract (P for trend = .004), whereas there was no significant association noted between incense use and nonsquamous cell carcinomas. The relative risk of squamous cell carcinomas among long-term incense users was 1.8 (95% confidence interval [95% CI], 1.2-2.6; P = .004) in the entire respiratory tract.

CONCLUSIONS

The results of the current study indicate that long-term use of incense is associated with an increased risk of squamous cell carcinoma of the respiratory tract.

Incense smoke: clinical, structural and molecular effects on airway disease

In Asian countries where the Buddhism and Taoism are mainstream religions, incense burning is a daily practice. A typical composition of stick incense consists of 21% (by weight) of herbal and wood powder, 35% of fragrance material, 11% of adhesive powder, and 33% of bamboo stick. Incense smoke (fumes) contains particulate matter (PM), gas products and many organic compounds. On average, incense burning produces particulates greater than 45 mg/g burned as compared to 10 mg/g burned for cigarettes. The gas products from burning incense include CO, CO₂, NO₂, SO₂, and others. Incense burning also produces volatile organic compounds, such as benzene, toluene, and xylenes, as well as aldehydes and polycyclic aromatic hydrocarbons (PAHs). The air pollution in and around various temples has been documented to have harmful effects on health. When incense smoke pollutants are inhaled, they cause respiratory system dysfunction. Incense smoke is a risk factor for elevated cord blood IgE levels and has been indicated to cause allergic contact dermatitis. Incense smoke also has been associated with neoplasm and extracts of particulate matter from incense smoke are found to be mutagenic in the Ames Salmonella test with TA98 and activation. In order to prevent airway disease and other health problem, it is advisable that people should reduce the exposure time when they worship at the temple with heavy incense smokes, and ventilate their house when they burn incense at home.

Polycyclic aromatic hydrocarbons in indoor air and dust in Kuwait: implications for sources and nondietary human exposure

This study reports concentration of polycyclic aromatic hydrocarbons (PAHs) in indoor air and dust samples collected from 24 homes in Kuwait. Mean SigmaPAHs in indoor air ranged from 1.3 to 16 ng/m(3) with a geometric mean of 5.6 ng/m(3), whereas the dust concentrations varied over three orders of magnitude, from 3 to 2920 ng/g, with a geometric mean of 165 ng/g. The low-molecular-weight tricyclic and tetracyclic PAHs dominated the air profile constituting approximately 70-90 % of the measured compounds, with phenanthrene (51%), fluorene (13 %), fluoranthere (8 %), and pyrene (7 %) being the major contributors. The PAH profile in dust was dominated by the high-molecular-weight PAHs, with three compounds (benzo[a]pyrene, benzo[k]fluoranthene, and benzo[b]fluoranthene) contributing approximately 60% of the average SigmaPAHs measured in the samples. Indoor-to-outdoor (I/O) ratios for individual compounds were <1 for the majority of compounds, suggesting that there were no significant indoor sources for these compounds in these homes. Using the measured concentrations in air and dust, together with estimates of inhalation and inadvertent dust ingestion rates for children and adults, estimated human nondietary exposure on a BaP(equiv) basis were 547 pg/kg body weight/day and 205 pg/kg body weight/day for children and adults, respectively. Exposure from dust ingestion contributes about 42% of nondietary intake of SigmaPAHs in children, but only 11% for adults. The threefold difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors.

Urinary 1‐Hydroxypyrene Level Relative to Vehicle Exhaust Exposure Mediated by Metabolic Enzyme Polymorphisms

Polycyclic aromatic hydrocarbons (PAH) are common air pollutants generated from incomplete combustion. The inhalation of exhaust fumes in urban areas has been suggested to be an additional contributing factor. This study investigated the influence of urban traffic exposure, personal lifestyle factors and metabolic enzyme polymorphisms on the urinary 1-hydroxypyrene (1-OHP) level, approximating exposure to PAH. With consents, 95 male taxi drivers exposed to vehicle exhaust in traffic and 75 male office employees received health interviews and provided urine samples. The results showed taxi drivers had higher urinary 1-OHP than the office employees (mean +/- standard deviation were 0.17 +/- 0.10 vs. 0.10 +/- 0.07 mol/mol creatinine, p<0.001). The average urinary 1-OHP level increased from 0.07 micromol/mol creatinine for non-smoking office employees to 0.17 micromol/mol creatinine for those who smoked more than 20 cigarettes daily. The values for taxi drivers with similar smoking statuses were 0.12 and 0.25 micromol/mol creatinine, respectively. Among non-smokers, taxi drivers still had higher 1-OHP level than office employees (0.12 +/- 0.05 vs. 0.07 +/- 0.03 micromol/mol creatinine). The subjects with the m1/m2 or m2/m2 genotype of CYP1A1 MspI or GSTM1 deficiency had significantly higher urinary 1-OHP levels than those with other CYP1A1 MspI and GSTM1 genotypes. Multivariate logistic regression analysis showed that taxi drivers (adjusted odds ratio (OR)=5.1, 95% confidence interval (CI)=1.1-13.6), smokers (OR=5.5, 95% CI=1.6-18.4) and subjects with the m1/m2 or m2/m2 genotype of CYP1A1 MspI (OR=9.7, 95% CI=2.7-35.0) had elevated urinary 1-OHP (greater than the overall median value, 0.11 micromol/mol creatinine). The results of this study suggest smoking contributes to the elevated urinary 1-OHP levels in taxi drivers in addition to taxi driving, and the excess level contributed from traffic exhaust and smoke was regulated by the CYP1A1 MspI genotype. Traffic exhaust exposure, smoking and CYP1A1 MspI genotype contributed to the variation in levels of urinary 1-OHP excretion.