Polycyclic Aromatic Hydrocarbons In Indoor Air Research Articles

Primary and Secondary Emissions of VOCs and PAHs in Indoor Air from a Waterproof Coal-Tar Membrane: Diagnosis and Remediation

Primary and secondary emissions of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) from a waterproof coal tar membrane and their effect on the indoor air quality were investigated through a case study in a residential building situated in Madrid, Spain. The air contaminants were analyzed in situ using photoionization method and several samples of contaminants were taken using three sorbents: activated carbon, XAD2 and Tenax GR. It was found that various VOCs such as toluene, p- and m-Xylene, PAHs such as naphthalene, methyl-naphthalenes, acenaphthene, acenaphthylene, phenanthrene and fluorine, volatile organic halogens including chloroform and trichlorofluoromethane, and alkylbenzene (1,2,4-trimethylbenzene) were found at concentrations, which exceeded the limits established by international and national agencies (WHO, EPA, OSHA). Some of the above organic compounds were found also in the samples of construction and building materials, which were obtained at different heights and places. The analysis of possible sources of the contaminants pointed at the original coal-tar membrane, which was applied on the terrace to be waterproof. During a posterior reparation the membrane was coated with a new one that hindered dissipation of emitted contaminants. The contaminants leached out and were absorbed by construction materials down in the dwelling. These materials then acted as secondary emission sources. To remediate the emission problem as the contaminated materials were removed and then a ventilation system was installed to force the gasses being emitted from the rest of contaminated slab outside. Follow-up has validated the success of the remediation procedure.

Polycyclic aromatic hydrocarbons (PAHs) in indoor air and dust samples of different Saudi microenvironments; health and carcinogenic risk assessment for the general population

In this study, the presence of polycyclic aromatic hydrocarbons (PAHs) was studied in indoor air (PM10) and settled dust collected from different indoor microenvironments of Saudi Arabia. Limited data is available on the indoor quality of Saudi Arabia and to the best of our knowledge, this is the first study reporting PAHs in indoor air from Saudi Arabia. The main objectives were to study the levels and profile of selected PAHs in indoor dust and PM10 samples from different microenvironments of Saudi Arabia and to estimate health risk assessment to the local population via inhalation, dust ingestion and dermal contact. To study PAHs, indoor dust and PM10 samples were collected from different households, offices and hotel roomsPM10.Pyrene, benz(a)anthracene, chrysene, and phenanthrene were the major PAHs in both settled dust and PM10 samples. Profile of PAHs in dust samples was dominated by 3 and 4 ring PAHs while in PM10 sample 5–6 aromatic ring PAHs also contributed significantly. PM10 collected from kitchens and AC filter dust samples were the most contaminated with PAHs. PM10Health risk assessment was made for adults and young based on benzo(a)pyrene equivalent carcinogenic power (BaPE) and incremental lifetime cancer risk (ILCR). BaPE revealed major toxicity threat associated with PAHs is all microenvironments samples (dust and PM10) is from 5 and 6 aromatic rings PAHs. ILRC calculated using ingestion, inhalation and dermal contact was within the limits set by USEPA and although using max concentration it was up to 8.0E-05, which can have significant impact long term if other exposure pathways such as food and outdoor exposure, etc. are considered.

Exposure and risk assessment of PAHs in indoor air of waterpipe cafés in Ardebil, Iran

The aim of this study was to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) bound to particulate matter (PM) in the indoor air of waterpipe cafés of Ardebil city, and to further assess the health risk due to exposure to PAHs. 50 out of 236 cafés were selected using systematic random sampling method and air samples were taken from standing breathing zone of smokers and employees, ∼150 cm above the ground level. The concentrations of PAHs were determined using GC-MS. The results showed that the mean indoor concentration of PAHs in the cafés was 5522.1 ± 594.8 ng/m3. It was 5915.2 ± 650.5, 2404 ± 271.4, and 7304.9 ± 846.0 ng/m3 for cafés with fruit flavored tobacco, regular tobacco, and the both, respectively. The means of the hazard quotient (HQ) for PAHs in different age groups, including 11 to <16, 16 to <21, 21 and older, and the cafés employees were 0.35, 0.75, 3.65, and 18, respectively. Also, the mean of estimated cancer risk for PAHs in the aforementioned age groups and employees were 0.65 (10−5), 1.31(10−5), 6.43 (10−5) and 31.3 (10−5), respectively. The results indicated the increased health risk levels related to the inhalation of tobacco smoke due to PAHs concentrations in the waterpipe cafés.

Electronic Shiazo waterpipes: anew source of indoor air pollutants

For some time, anew form of waterpipe smoking has been advertised, where steam stones moistened with aroma fluids (Shiazo) are heated electronically. Since there is no combustion of tobacco, it is often assumed that the produced vapor is not harmful to health. To clarify this issue, we performed acomprehensive inner and outer exposure assessment during the use of an electronic Shiazo waterpipe. Three volunteers smoked an electronic waterpipe operated with nicotine-free Shiazo stones in athoroughly ventilated room for 2 h. In three smoking sessions, three fluids with different flavorings were vaporized. In parallel, emissions of particles, volatile organic compounds, polycyclic aromatic hydrocarbons (PAH), and metals were measured in indoor air. Within abiomonitoring study, urinary metabolite profiles of air pollutants were checked. For comparison, the components of the Shiazo fluids were also analyzed. During the smoking sessions, concentrations of formaldehyde, acetaldehyde, glycerine, and propylene glycol rose significantly in the indoor environment. The content of putative carcinogenic PAH in indoor air increased by 42% to 174 ng/m3. Particle number concentrations ranged from 39,968 to 65,610 particles/cm3 (median), with peaks at diameters from 25 to 31 nm. 3‑HPMA, the mercapturic acid metabolite of the pyrolysis product acrolein, was strongly elevated in urine samples of the smokers. All fluids contained high amounts of contact allergens. Electronic Shiazo waterpipes release various harmful substances that considerably impact indoor air quality. Compared to conventional waterpipes, the release of pollutants is lower. Nevertheless, smoking with Shiazo waterpipes is a source of health risks for both users and bystanders.

Development of a short path thermal desorption–gas chromatography/mass spectrometry method for the determination of polycyclic aromatic hydrocarbons in indoor air

Polycyclic aromatic hydrocarbons (PAHs) are present in petroleum based products and are combustion by-products of organic matters. Determination of levels of PAHs in the indoor environment is important for assessing human exposure to these chemicals. A new short path thermal desorption (SPTD) gas chromatography/mass spectrometry (GC/MS) method for determining levels of PAHs in indoor air was developed. Thermal desorption (TD) tubes packed with glass beads, Carbopack C, and Carbopack B in sequence, were used for sample collection. Indoor air was sampled using a small portable pump over 7 days at 100ml/min. Target PAHs were thermally released and introduced into the GC/MS for analysis through the SPTD unit. During tube desorption, PAHs were cold trapped (−20°C) at the front end of the GC column. Thermal desorption efficiencies were 100% for PAHs with 2 and 3 rings, and 99–97% for PAHs with 4–6 rings. Relative standard deviation (RSD) values among replicate samples spiked at three different levels were around 10–20%. The detection limit of this method was at or below 0.1μg/m3 except for naphthalene (0.61μg/m3), fluorene (0.28μg/m3) and phenanthrene (0.35μg/m3). This method was applied to measure PAHs in indoor air in nine residential homes. The levels of PAHs in indoor air found in these nine homes are similar to indoor air values reported by others.

Tenax-TA Spiking Approach of Thermal Desorption Coupled to GC–MSMS for the Quantification of PAHs in Indoor Air and Dust

ABSTRACTA method coupling automated thermal desorption and gas chromatography-tandem mass spectrometry was developed and used for the quantification of 16 PAHs (acenaphthene, anthracene, benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[e]pyrene, benzo[g,h,i]perylene, benzo[k]fluoranthene, chrysene, dibenzo[a,h]anthracene, fluoranthene, fluorene, indeno(1, 2, 3)pyrene, naphthalene, phenanthrene and pyrene) in indoor air and dust. Polycyclic aromatic hydrocarbons (PAHs) in indoor air were sampled using Tenax-TA passive samplers (PAS) exposed during 14 days. Indoor dust, collected on filters using a modified vacuum cleaner head equipped with a sieving device, was first extracted using accelerated solvent extractor. The extract was then concentrated and deposed on a Tenax-TA tube prior to analysis. Using the same thermal desorption method for the analysis of two different matrices gives complementary results with good sensitivity. Limit of detection varied between 0.009 and 0.031 ng and between 0.076 and 0.22 ng/g for PAS and dust, respectively. Likewise, limit of quantification varied between 0.03 and 0.10 ng and between 0.253 and 0.733 ng/g. Results showed that indoor PAH concentrations remains constant, whereas outdoor contamination presents high variability depending on conditions.

Heat and PAHs Emissions in Indoor Kitchen Air and Its Impact on Kidney Dysfunctions among Kitchen Workers in Lucknow, North India.

Indoor air quality and heat exposure have become an important occupational health and safety concern in several workplaces including kitchens of hotels. This study investigated the heat, particulate matter (PM), total volatile organic compounds (TVOCs) and polycyclic aromatic hydrocarbons (PAHs) emissions in indoor air of commercial kitchen and its association with kidney dysfunctions among kitchen workers. A cross sectional study was conducted on 94 kitchen workers employed at commercial kitchen in Lucknow city, North India. A questionnaire-based survey was conducted to collect the personal and occupational history of the kitchen workers. The urine analysis for specific gravity and microalbuminuria was conducted among the study subjects. Indoor air temperature, humidity, wet/ dry bulb temperature and humidex heat stress was monitored during cooking activities at the kitchen. Particulate matter (PM) for 1 and 2.5 microns were monitored in kitchen during working hours using Hazdust. PAHS in indoor air was analysed using UHPLC. Urinary hydroxy-PAHs in kitchen workers were measured using GC/MS-MS. Higher indoor air temperature, relative humidity, PM1 and PM2.5 (p<0.001) was observed in the kitchen due to cooking process. Indoor air PAHs identified are Napthalene, fluorine, acenaphthene, phenanthrene, pyrene, chrysene and indeno [1,2,3-cd) pyrene. Concentrations of all PAHs identified in kitchen were above the permissible OSHA norms for indoor air. Specific gravity of urine was significantly higher among the kitchen workers (p<0.001) as compared to the control group. Also, the prevalence of microalbuminuria was higher (p<0.001) among kitchen workers. Urinary PAH metabolites detected among kitchen workers were 1-NAP, 9-HF, 3-HF, 9-PHN and 1-OHP. Continuous heat exposure in kitchens due to cooking can alter kidney functions viz., high specific gravity of urine in kitchen workers. Exposure to PM, VOCs and PAHs in indoor air and presence of urinary PAHs metabolites may lead to inflammation, which can cause microalbuminuria in kitchen workers, as observed in the present study.

An analytical method coupling accelerated solvent extraction and HPLC-fluorescence for the quantification of particle-bound PAHs in indoor air sampled with a 3-stages cascade impactor

Most of Polycyclic Aromatic Hydrocarbons (PAHs) are associated to airborne particles and their health impact depends on the particle size where they are bound. This work aims to develop a high sensitive analytical technique to quantify particulate PAHs sampled with a 3-stages cascade impactor in order to derive simultaneously their individual concentration in PM1, PM2.5 and PM10.Three key steps of the method were evaluated separately in order to avoid any PAHs loss during the global sample preparation procedure: (1) the accelerated solvent extraction of PAHs from the filter; (2) the primary concentration of the extract until 1mL by means of a rotary evaporator at 45°C and 220mbar and (3) the final concentration of the pre-concentrated extract to about 100–150µL under a gentle nitrogen stream. Each recovery experiment was realized in triplicates. All these steps evaluated independently show that the overall PAHs loss, even for those with a low molecular weight, should not exceed more than a few percent. Extracts were then analyzed by using a HPLC coupled to fluorescence and Diode Array Detectors with the external standard method.The resulting calibration curves containing between 9 and 12 points were plotted in the concentration range of 0.05–45µgL−1 for most of the 16 US-EPA priority PAHs and were fully linear (R2>0.999). Limits Of Quantification were in the range 0.05–0.47µgL−1 corresponding to 0.75–7.05pgm−3 for 20m3 of pumped air.Finally, taking into account the average PAHs concentrations previously reported in typical European indoor environments, and considering the use of a 3-stages cascade impactor to collect simultaneously PM>10µm, 2.5µm<PM<10µm, 1µm<PM<2.5µm and PM<1 (and then to derive PM1, PM2.5 and PM10) for particle-bound PAHs quantification, the sampling duration was estimated to 20–40h for a sampling flow fixed to 0.5m3h−1.

Use of electronic cigarettes (e-cigarettes) impairs indoor air quality and increases FeNO levels of e-cigarette consumers

Despite the recent popularity of e-cigarettes, to date only limited data is available on their safety for both users and secondhand smokers. The present study reports a comprehensive inner and outer exposure assessment of e-cigarette emissions in terms of particulate matter (PM), particle number concentrations (PNC), volatile organic compounds (VOC), polycyclic aromatic hydrocarbons (PAH), carbonyls, and metals. In six vaping sessions nine volunteers consumed e-cigarettes with and without nicotine in a thoroughly ventilated room for two hours. We analyzed the levels of e-cigarette pollutants in indoor air and monitored effects on FeNO release and urinary metabolite profile of the subjects. For comparison, the components of the e-cigarette solutions (liquids) were additionally analyzed. During the vaping sessions substantial amounts of 1,2-propanediol, glycerine and nicotine were found in the gas-phase, as well as high concentrations of PM2.5 (mean 197 μg/m(3)). The concentration of putative carcinogenic PAH in indoor air increased by 20% to 147 ng/m(3), and aluminum showed a 2.4-fold increase. PNC ranged from 48,620 to 88,386 particles/cm(3) (median), with peaks at diameters 24-36 nm. FeNO increased in 7 of 9 individuals. The nicotine content of the liquids varied and was 1.2-fold higher than claimed by the manufacturer. Our data confirm that e-cigarettes are not emission-free and their pollutants could be of health concern for users and secondhand smokers. In particular, ultrafine particles formed from supersaturated 1,2-propanediol vapor can be deposited in the lung, and aerosolized nicotine seems capable of increasing the release of the inflammatory signaling molecule NO upon inhalation. In view of consumer safety, e-cigarettes and nicotine liquids should be officially regulated and labeled with appropriate warnings of potential health effects, particularly of toxicity risk in children.

Calculated respiratory exposure to indoor size-fractioned polycyclic aromatic hydrocarbons in an urban environment

Polycyclic aromatic hydrocarbons (PAHs) associated with inhalable particles are harmful to human health, especially to people in urban indoor environments. To evaluate human respiratory exposure to indoor PAHs properly, respiratory deposition fluxes of size-fractioned PAHs were estimated based on size-segregated distribution of PAHs in indoor air of an urban community of Guangzhou, China. The concentrations of ∑16PAH (sum of the 16 priority PAHs designated by the United States Environmental Protection Agency) were 28.9±10.0ng/m3, with the mean benzo(a)pyrene equivalent (BaPE) concentration at 4.1±1.6ng/m3. Particle size distributions of both ∑16PAH and BaPE concentrations peaked in the 1.0–1.8μm fraction. The mean respiratory deposition flux of ∑16PAH was 5.9ng/h, and accumulation mode particles contributed 20.5–83.8% of the respiratory deposition fluxes for individual PAHs. In addition, 8.6–10.2% of inhaled ∑16PAH were calculated to be deposited in the alveoli region, with accumulation particles as the largest contributor. In particular, ultrafine particles contributed 0.4–21.7% of individual PAHs deposited in the alveoli region, more than twice the fraction of the PAHs in the ultrafine particles (0.2–8.5%). Finally, lifetime cancer risk via inhalation of indoor particulate PAHs may be greater than the cancer risk guideline value (10−6), depending on specific assumptions used in this risk assessment.

THE COOKING USING DIFFERENT FUELS AND THE LEVEL OF INDOOR AIR PAHS

Background and Aims: To understand the impact of cooking by daily fuels on the levels of indoor air polycyclic aromatic hydrocarbons (PAHs). Methods: Four households with similar house structure and economic conditions were chosen in a village of North Jiangsu province. Fuels (including straw, coal and liquefied petroleum gas (LPG)) were used to cook the same foods in each kitchen. Indoor air PAHs (including those adsorbed on PM10 and in gaseous state) were collected and detected during cooking. Results: The majority of PAHs (including PAHs adsorbed on PM10 and in gaseous state) in indoor air produced by all 3 fuels burning was those under 4-ring and gaseous PAHs. The median percentages of PAHs under 4-ring and in gaseous state accounting for total PAHs were 93.86% (93.63% ~ 94.52%) and 94.20% (81.36% ~ 94.34%), respectively. The levels of total PAHs in kitchen air produced by straw, coal and LPG burning were 4.70μg/m3, 3.91μg/m3 and 3.65μg/m3, respectively. The levels of gaseous PAHs in kitchen air brought by all 3 fuels combustion were higher than those adsorbed on PM10. The median difference between gaseous and adsorbed on PM10 was 3.05μg/m3 (2.49μg/m3 ~ 3.29μg/m3). The levels of PAHs adsorbed on PM10 in kitchen air produced by straw, coal and LPG burning were 0.738μg/m3, 0.204μg/m3 and 0.198μg/m3 respectively, while the levels of gaseous PAHs were 3.97μg/m3, 3.70μg/m3 and 3.45μg/m3 respectively. PAHs under 4-ring adsorbed on PM10 accounted for 64.22% (63.13%~82.52%). PAHs under 4-ring dominated gaseous PAHs and received 95% (95.49% ~ 96.41%) as well. Conclusions: The majority of PAHs in indoor air brought by all 3 fuels combustion was PAHs under 4-ring and in gaseous state. Straw burning produced the maximum PAHs, coal finished the second, and LPG got the minimum.

Pollution level, phase distribution and source analysis of polycyclic aromatic hydrocarbons in residential air in Hangzhou, China

A survey of polycyclic aromatic hydrocarbons (PAHs) in residential air in Hangzhou, China, was carried out. Air samples were collected from indoor and outdoor environments during both summer and winter and analyzed for the level of 16 PAHs. The results showed total PAH contents ranging from 0.425 to 36.2 μg/m 3 with highest concentrations in the kitchen areas generally. Particulate PAHs were predominantly absorbed on PM 2.5 with proportion of 59–97% to total particulate phase, followed by PM 2.5–10 (3–24%) and PM >10 (0–17%). PAH concentrations in indoor air of smoking residences tended to be higher than those of nonsmoking residences. Outdoor environment, Chinese conventional cooking practice, mothball emission and unknown source accounted for −10.5%, 32.8%, 71.5% and 6.2% of total PAHs in indoor air of nonsmoking residences, respectively. Outdoor environment was the fate for indoor PAHs in general, and consumed 10.5% of total PAHs. Finally, health risks associated with the inhalation of PAHs were assessed, and the results indicated that health-based guideline levels for lung cancer risk were exceeded. The largest contribution to total health risks in summer and winter was NA (72.9%) and BaP (45.2%), respectively.

Criterion Catalysts to sell services units and alumina stake

A survey of polycyclic aromatic hydrocarbons (PAHs) in residential air in Hangzhou, China, was carried out. Air samples were collected from indoor and outdoor environments during both summer and winter and analyzed for the level of 16 PAHs. The results showed total PAH contents ranging from 0.425 to 36.2 μg/m3 with highest concentrations in the kitchen areas generally. Particulate PAHs were predominantly absorbed on PM2.5 with proportion of 59–97% to total particulate phase, followed by PM2.5–10 (3–24%) and PM>10 (0–17%). PAH concentrations in indoor air of smoking residences tended to be higher than those of nonsmoking residences. Outdoor environment, Chinese conventional cooking practice, mothball emission and unknown source accounted for −10.5%, 32.8%, 71.5% and 6.2% of total PAHs in indoor air of nonsmoking residences, respectively. Outdoor environment was the fate for indoor PAHs in general, and consumed 10.5% of total PAHs. Finally, health risks associated with the inhalation of PAHs were assessed, and the results indicated that health-based guideline levels for lung cancer risk were exceeded. The largest contribution to total health risks in summer and winter was NA (72.9%) and BaP (45.2%), respectively.

Simultaneous Liquid Chromatographic Determination of 39 Polycyclic Aromatic Hydrocarbons in Indoor and Outdoor Air and Application to a Survey on Indoor Air Pollution in Fuji, Japan

An analytical method was established for the simultaneous determination of 39 polycyclic aromatic hydrocarbons (PAHs) in air. The method was applied to a survey of gaseous and particulate PAHs in household indoor air. The survey was performed in 21 houses in the summer of 1999 and in 20 houses in the winter of 1999-2000 in Fuji, Japan. Thirty-eight PAHs were determined in indoor and outdoor air in the summer, and 39 PAHs were determined in indoor and outdoor air in the winter. The concentrations of gaseous PAHs in indoor air tended to be higher than those in outdoor air in the summer and winter. The concentrations of particulate PAHs in indoor air were the same as or lower than those in outdoor air in the summer and winter. PAH profiles, correlations between PAH concentrations, and multiple regression analysis were used to determine the factors affecting the indoor PAH concentrations. These results showed that gaseous PAHs in indoor air were primarily from indoor emission sources, especially during the summer, and that indoor particulate PAH concentrations were significantly influenced by outdoor air pollution.

PAH Exposures of Nine Preschool Children

The exposures to 20 polycyclic aromatic hydrocarbons (PAH) of 9 children, ages 2–5 yr, were measured over 48 hr at day care and at home. Sampled media included indoor and outdoor air, floor dust, outdoor play area soil, hand surface, and solid and liquid food. Urine samples were collected for metabolite analysis. Diaries of the children's activities during the sampling period were also kept. Significant positive correlations between media were found for total PAH in indoor air with floor dust (p<0.001), and for total PAH in outdoor air with floor dust (p<0.05). Also at the p<0.05 level, the B2 PAH (probable human carcinogens) were correlated in play area soil with outdoor air, and in outdoor with indoor air. Total PAH and B2 concentrations were correlated in play area soil and in floor dust (p<0.05). The relative importance of the exposure pathways differed for total PAH and B2 PAH. For total PAH, which included both volatile and semi-volatile compounds, inhalation was most important, then dietary ingestion, then non-dietary ingestion. In contrast, for the B2 PAH only, non-dietary ingestion was most important, then dietary ingestion, and inhalation was least important. Differences in the children's PAH exposures were small between day care and home, and also between children from low-income and from middle-income families.

The effect of coal stoves and environmental tobacco smoke on the level of urinary 1-hydroxypyrene

The objective of this study was to investigate a relationship between indoor air pollution from heating and cooking with coal-burning stoves and from environmental tobacco smoke (ETS), and the level of urinary 1-hydroxypyrene (1-OH-PY). 1-OH-PY was analysed in children living in three areas of Silesia, a province in Poland. Urine samples were collected in winter, (1) from children exposed to ETS and smoke resulting from indoor coal-burning and (2) from control children. Airborne particulates had been sampled by use of stationary samplers by the Regional Sanitary–Epidemiological Station, Katowice throughout 12 months prior to the urine sampling. The urinary level of 1-OH-PY tended to increase in children exposed to ETS, but the increase was not significant. The concentrations of 1-OH-PY in urine of passive smokers were significantly elevated only in Bytom where an index of smoking parents of the studied children was highest as compared to other areas. Exposure to polycyclic aromatic hydrocarbons (PAH) due to domestic heating and cooking with coal-burning stoves resulted in significantly increased levels of 1-OH-PY. The results of this study indicate that the uptake of PAH due to indoor air pollution strongly affected the level of 1-OH-PY and that the main source of PAH in indoor air was the household use of coal for heating and/or cooking. When the results associated with this kind of exposure were excluded, median 1-OH-PY levels from the three examined areas assumed a pattern more similar to that of the benzo( a)pyrene (BaP) concentrations in ambient air.

Indoor and outdoor air pollution in Tokyo and Beijing supercities

Since automobile exhaust and coal combustion exhaust are the major sources of suspended particulate matter (SPM) and airborne pollutants in many countries, SPM and polycyclic aromatic hydrocarbons (PAH) in indoor and outdoor air were measured using the new portable samplers (AND sampler) around a main road and in residential areas of Tokyo and Beijing. The results showed that the relationship between the airborne particle concentration in indoor air and outdoor air varied with the aerodynamic diameter of the particles. The concentration of SPM in indoor air increased in proportion to that in outdoor air. The concentration of PAH and mutagenic activity in air also varied with the aerodynamic diameter of the particles. Fine particles exhibiting an aerodynamic diameter of < 2 μm contained high concentrations of PAH and mutagens. The concentrations of benzo( k)fluoranthene, benzo( a)pyrene [B( a)P], and benzo( ghi)perylene in indoor air increased in proportion to those in outdoor air around a main road and in residential areas of Tokyo and Beijing. The results showed that fine particles seemed to be more harmful to humans than coarse ones. In the winter season, the SPM and sulfur dioxide concentration in indoor and outdoor air in residential areas of Beijing was approximately 4 to 5 times higher than that around a main road of Tokyo. The B( a)P concentration in outdoor air in residential areas of Beijing was approximately 15 times higher than that in residential areas around a main road of Tokyo. Since the concentration of SPM and PAH in indoor air increases in proportion to that in outdoor air, it is reasonable to make efforts to reduce SPM and PAH generated by automobile exhaust in Tokyo and coal combustion exhaust in Beijing.