Study of respirable suspended particulates and polycyclic aromatic hydrocarbons in indoor and outdoor air.

To study the concentration change of respirable suspended particulate (RSP) in indoor and outdoor air environment, a new portable sampler (AND-sampler) was made. The sampler could collect particles above 10 microns, 2 to 10 microns, and below 2 microns in aerodynamic diameter separately. The relationship between the airborne particulate concentration in indoor and outdoor air environment varied with the aerodynamic diameter of the particles. The concentration of RSP in indoor air environment increased in proportion to that in outdoor environment. Polycyclic aromatic hydrocarbons (PAH) concentration in airborne particulate also varies with the aerodynamic diameter of the particles. Fine particles below 2 microns in aerodynamic diameter contains high concentration of PAH. The PAH concentration in indoor air environment increases in proportion to that in outdoor air.     

Study on suspended particulate matter and polycyclic aromatic hydrocarbons in indoor and outdoor air

Summary To study changes in the concentration of suspended particulate matter (SPM) in indoor and outdoor air, a new portable sampler (AND sampler) was designed that could separately collect particles exhibiting aerodynamic diameters of > 10 m, 2–10 m, and < 2 m. The relationship between the airborne particle concentration in indoor air and that in outdoor air varied with the aeordynamic diameter of the particles. The concentration of SPM in the indoor air increased in proportion to that in the outdoor air. The concentration of polycyclic aromatic hydrocarbons (PAH) in SPM also varied with the aerodynamic diameter of the particles. Fine particles exhibiting an aerodynamic diameter of < 2 m contained high concentration of PAH. The concentrations of benzo(k)fluoranthene, benzo(a)pyrene, and benzo (ghi) perylene in indoor air increased in proportion to those in outdoor air.     

Evaluation of cytokine expression in BEAS cells exposed to fine particulate matter (PM2.5) from specialized indoor environments

Fine particles were collected in three indoor environments and an outdoor reference site. Samples were acid and aqueous extracted for metal analyses and cytokine expression study using a BEAS-2B line. Results revealed that the average PM(2.5) concentration indoors was 5.8 μg/m(3) while outside, it was 9.4 μg/m(3). The airborne metal concentrations in indoor air ranged from 0.01 ng/m(3) (Cd) to 620 ng/m(3) (Al). All metals analyzed were higher indoors when compared to outdoor (I/O ratio) indicating a contribution from the workplace. Some metals were more efficiently extracted (e.g., Ni, V, As) in the aqueous phase than others (e.g., Fe and Al). Toxicological assays showed that the aqueous extracts at 20% induced IL-6 and subsequently inhibited it at a higher concentration (50%); both IL-8 and MCP-1 were inhibited at 20 and 50%. As, Ni and V concentrations seem to be the most important metals associated with the cytokine induction/inhibition response probably due to the higher bioavailability.     

Polycyclic aromatic hydrocarbons bound to outdoor and indoor airborne particles (PM2.5) and their mutagenicity and carcinogenicity in Silesian kindergartens,Poland

Assessment of exposure to polycyclic aromatic hydrocarbons (PAHs) is important due to the widespread presence of PAHs in the environment and their toxicological relevance, especially to susceptible populations such as children and their health. The aim of this study is to compare indoor and outdoor concentrations of particulate matter with a diameter of 2.5 μm or less (PM2.5) and 15 individual PAHs, as well as contribution of the analyzed PAHs to mutagenic and carcinogenic activity. Samples were collected during spring season in two sites in southern Poland (Silesia) representing urban and rural areas. Indoor samples of PM2.5 were sampled in kindergartens. At the same time, in the vicinity of the kindergarten buildings, the collection of the outdoor PM2.5 samples was carried out. Mutagenic (MEQ) and carcinogenic (TEQ) equivalents related to BaP and the percentage share expressed as mutagenic (MP) and carcinogenic (CP) potential of each individual compound to the total mutagenic/carcinogenic potential of the PAH mixture were calculated. The obtained results show that high concentrations of PM2.5 (above 25 μg/m³) and 15 PM2.5-bound PAHs in outdoor and indoor air were similar in the two studied areas. In overall PAHs mutagenic and carcinogenic potential, the percentage share of benzo(a)pyrene (BaP) was dominant and varied from 49.0–54.5% to 62.5–70.0%, respectively. The carried out study indicates the necessity of reducing PAH emission from solid fuel combustion, which is reflected in PM2.5-bound PAHs concentrations and their diagnostic ratios. In the recent years, health effects on children resulting from their activity pattern and air quality in the public places have been a serious problem.     

Characterization of indoor particle sources: A study conducted in the metropolitan Boston area

An intensive particle monitoring study was conducted in homes in the Boston, Massachusetts, area during the winter and summer of 1996 in an effort to characterize sources of indoor particles. As part of this study, continuous particle size and mass concentration data were collected in four single-family homes, with each home monitored for one or two 6-day periods. Additionally, housing activity and air exchange rate data were collected. Cooking, cleaning, and the movement of people were identified as the most important indoor particle sources in these homes. These sources contributed significantly both to indoor concentrations (indoor-outdoor ratios varied between 2 and 33) and to altered indoor particle size distributions. Cooking, including broiling/baking, toasting, and barbecuing contributed primarily to particulate matter with physical diameters between 0.02 and 0.5 microm [PM((0.02-0.5))], with volume median diameters of between 0.13 and 0.25 microm. Sources of particulate matter with aerodynamic diameters between 0.7 and 10 microm [PM((0.7-10))] included sautéing, cleaning (vacuuming, dusting, and sweeping), and movement of people, with volume median diameters of between 3 and 4.3 microm. Frying was associated with particles from both PM((0.02-0.5)) and PM((0.7-10)). Air exchange rates ranged between 0.12 and 24.3 exchanges/hr and had significant impact on indoor particle levels and size distributions. Low air exchange rates (< 1 exchange/hr) resulted in longer air residence times and more time for particle concentrations from indoor sources to increase. When air exchange rates were higher (> 1 exchange/hr), the impact of indoor sources was less pronounced, as indoor particle concentrations tracked outdoor levels more closely.     

Exposure to wood dust and heavy metals in workers using CCA pressure-treated wood

Chemical pesticide treatment enables relatively nonresistant woods to be used in outdoor construction projects. The most prevalent procedure used to protect these woods is pressure treatment with chromium, copper, and arsenic (CCA). This pilot study examined the airborne concentration and particle size distribution of wood particles, chromium, copper, and arsenic at both outdoor (measured over the whole work day) and indoor (measured during the performance of specific tasks) work sites. At the outdoor residential deck construction sites, the arithmetic mean total dust concentration, measured using personal filter cassette samplers, was 0.57 mg/m3. The mass median aerodynamic diameter (da) of the outdoor wood dust was greater than 20 microm. Indoor wood dust concentrations were significantly greater than those measured outdoor and were job category-dependent. The highest mean breathing zone dust concentration, 49.0 mg/m3, was measured at the indoor sanding operation. Personal impactor sampling demonstrated that the mean total airborne concentration of arsenic, but not chromium or copper, was consistently above recommended occupational exposure levels at the indoor work site, and occasionally at the outdoor work sites. At the indoor sanding operation, the mean total chromium, copper, and arsenic concentrations were 345, 170, and 342 microg/m3, respectively. Thus, significant exposure to airborne heavy metals can occur as a result of indoor and outdoor exposure to CCA pressure-treated wood dust. Therefore, current standards for wood dust may not adequately protect workers from the heavy metals commonly used in CCA pressure-treated wood.     

A technique to expose animals to concentrated fine ambient aerosols.

This paper presents the development and evaluation of an ambient particle concentrator for conducting animal inhalation exposure studies. The system utilizes the principle of virtual impactors to concentrate ambient particles in the size range 0.1-2.5 microns (aerodynamic diameter; dp) by drawing them through a series of three virtual impactors. Each impactor contains the majority of ambient fine mass (dp < 2.5 microns aerodynamic diameter) in a bleed flow (minor flow) that is 20% of the total flow entering the virtual impactor. The virtual impactors have been characterized using indoor air samples as test aerosols. Fine mass and sulfate concentrations at the outlet of the concentrating system were compared to the ambient fine mass and sulfate levels, which were determined using Harvard-Marple impactors. In each of the stages, particle concentration was increased by a factor of approximately 3. Thus, an overall concentration factor of about 25-30 was achieved. The main goal of this study was to demonstrate the feasibility of conducting animal exposures using the newly developed ambient fine particle concentrator.     

Analysis of human exposure to benzo(a)pyrene via inhalation and food ingestion in the Total Human Environmental Exposure Study (THEES)

The Total Human Environmental Exposure Study (THEES) focuses on benzo(a)pyrene (BaP) as an example of a combustion-generated polycyclic aromatic hydrocarbon (PAH) compound. Primary pathways for environmental exposures to BaP are inhalation and ingestion. This program of field studies was conducted in Phillipsburg, New Jersey, a small, industrial city in the Delaware River valley. The study protocols included direct monitoring of BaP exposures via inhalation and ingestion pathways during three separate periods, each lasting 14 days. BaP concentrations in air were sampled at outdoor and in-home locations, with personal air sampling added during the latter two phases. Cooked food samples from each household were acquired, using a constant portion "second plate" of each meal prepared at home. Ambient levels were 4-10 times higher during the cold months compared with the late summer study period. Space heating and regional aerosol were major contributors to community levels of BaP in the air during the wintertime. Penetration of outdoor air, cooking activities, combustion appliances, and cigarette smoke were important sources of indoor air exposures. Cooking activities, besides releasing BaP-enriched particles indoors, produced food imbued with BaP and added substantially to exposure via the ingestion route. Among the study subjects, the range and magnitude of dietary exposures (2 to 500 ng/d) were much greater than for inhalation (10 to 50 ng/d). Nevertheless, there were ample individual cases where inhalation of BaP was the predominant exposure route. Indoor air BaP levels were closely correlated with ambient levels in most of the homes. For some individuals, measured personal air BaP exposures were adequately predicted by time-weighting of microenvironmental (i.e., outdoor and in-home) concentrations. However, enormously high exposures for ingestion or inhalation were detected only by direct observation, not from microenvironmental data.     

Real-time monitoring of particles, PAH, and CO in an occupied townhouse

Beginning in October 1996, indoor and sometimes outdoor air at an occupied house in a suburban area of Virginia has been monitored continuously for particles, PAH, and CO. Two Climet monitors have been used to count particles in six size ranges between 0.3 and > 10 microns, with 1-minute averages being collected every 5 minutes. Two Ecochem PAH monitors have been used to sample for particle-bound PAHs once every minute. Also, two Langan CO monitor-data loggers have measured CO once each minute while logging the PAH data. Two Aethalometers measure black carbon. A single Scanning Mobility Particle Sizer (SMPS) measures ultrafine particles. The pairs of monitors are set up either to provide an indoor/outdoor or an upstairs office/downstairs kitchen comparison. Air exchange is occasionally measured using a Bruel & Kjaer 1302 SF6 monitor, as a parameter necessary for estimating deposition rates for particles and PAH. Results from the first 16 months of monitoring (approximately 10 M observations) include: neighborhood woodburning and morning rush hour traffic are the most important sources of PAH and black carbon outdoors; candles, matches, incense, and frying, sauteeing, broiling, deep-frying, and stir-frying are additional important indoor sources of PM. One citronella candle was an extremely powerful PAH source. Neither woodburning nor vehicles appears to be an important source of particles indoors, but frying, grilling, and sauteeing are extremely strong indoor sources, together with combustion events such as use of matches and candles. Physical movement was an important source of coarse but not fine particles. Use of the gas stove for extended periods of time led to increased CO concentrations--vehicles and woodburning were relatively minor sources in comparison. The gas oven, gas burners, and electric toaster oven were important sources of ultrafine particles (< 0.1 micron). A source-proximity effect was noted with the kitchen monitor reading two to five times higher than the upstairs monitor for particles from kitchen events, while the upstairs monitor often read higher than the kitchen monitor for events caused by physical activity alone.     

Perceptions of indoor air quality associated with ventilation system types in elementary schools

With the increased utilization of school buildings on a year-round basis, school indoor air quality has become a national concern. The purpose of this study was to evaluate possible associations between ventilation system type and occupant perception of indoor air quality. Staff (n = 403) from 12 schools completed a self-administered questionnaire. Carbon dioxide (CO2) levels, air exchange rates, and particle counts were also measured for each school. Schools with unit ventilator (UV) systems had the lowest mean CO2 level at 637 ppm, followed by the variable air volume (VAV) systems with 664 ppm, and constant volume (CV) systems with a mean of 703 ppm. Schools with UV systems had the lowest mean air exchange rate at 2.67 air changes per hour (ACH), followed by the VAV system type at 2.80 ACH and the CV system type at 4.61 ACH. Indoor versus outdoor particle ratios were calculated for each ventilation system type. Particles with aerodynamic diameters ranging from 0.1-1.0 microm had a geometric mean ratio ranging from 0.38 to 0.68; particles with aerodynamic diameters ranging from 1-3 microm had ratios ranging from 1.39 to 5.47, and particles with aerodynamic diameters greater than 3 microm had ratios ranging from 3.20 to 14.76. Schools using VAV systems had a significantly lower prevalence of red and watery eyes while schools with UV systems had an elevated prevalence of nasal congestion, sore throat, headache, and dustiness complaints. This increased prevalence of complaints in buildings with UV systems may be due to the increased particulate levels.     

Influence of Number of Visitors and Weather Conditions on Airborne Particulate Matter Mass Concentrations at The Plitvice Lakes National Park,Croatia During Summer and Autumn

We investigated the influence of local meteorological conditions and number of visitors on ambient particulate matter (PM) mass concentrations and particle fraction ratios at the Plitvice Lakes National Park between July and October 2018. Outdoor mass concentrations of particles with aerodynamic diameters of less than 1, 2.5, and 10 μm (PM₁, PM_2.5, and PM₁₀, respectively) and indoor PM₁ were measured with two light-scattering laser photometers set up near the largest and most visited Kozjak Lake. Our findings suggest that the particles mainly originated from background sources, although some came from local anthropogenic activities. More specifically, increases in both indoor and outdoor mass concentrations coincided with the increase in the number of visitors. Indoor PM₁ concentrations also increased with increase in outdoor air temperature, while outdoor PMs exhibited U-shaped dependence (i.e., concentrations increased only at higher outdoor air temperatures). This behaviour and the decrease in the PM₁/PM_2.5 ratio with higher temperatures suggests that the production and growth of particles is influenced by photochemical reactions. The obtained spectra also pointed to a daily but not to weekly periodicity of PM levels.Key words: anthropogenic PM sources, bivariate polar plot, light-scattering laser photometry, weighted overlapped segment averaging     

上海市地铁地下车站室内微生物气溶胶分布特征分析

目的 了解上海市地铁车站室内空气中微生物分布状况。 方法 对地铁车站站台环境和室外环境中的细菌、真菌进行采样检测,并对数据进行统计学分析。 结果 车站内细菌菌落数低于室外对照点,真菌菌落数则高于室外,差异均有统计学意义(P<0.05)。地铁车站内颗粒粒径在4.70 μm以上的微生物数量低于室外对照点,差异有统计学意义(P<0.05)。地铁车站空气中微生物主要附着于0.65~4.70 μm粒径的颗粒物上。 结论 由于5.00 μm以下的颗粒可以进入到人体下呼吸道,富含致病微生物的颗粒物会对人体健康带来危害。地铁车站内粒径在5.00 μm以下的微生物气溶胶应成为重点监控对象。     

The Total Human Environmental Exposure Study (THEES) to benzo(a)pyrene: comparison of the inhalation and food pathways

The assessment of human exposure to an environmental contaminant requires the measurement of levels present in each pathway of possible contact. In this paper, the design considerations and Phase I results of a human exposure study focused on Benzo(a)pyrene (BaP) are discussed. This study site, located in Phillipsburg, New Jersey, is a city that contains a metal pipe foundry, which is a suspected major source of BaP. Three outdoor PM-10 samplers (used to collect BaP-containing particles with an aerodynamic size of less than or equal to 10 micron) were located in residential areas surrounding the foundry. Ten homes were sampled indoors for PM-10. Some homes have indoor combustion sources, e.g., cigarette smoke or a coal burning stove. The indoor and outdoor samples were 24 hr in duration. The mean outdoor concentration of BaP was 0.9 ng/m3, and the indoor concentrations ranged from 0.1-8.1 ng/m3. Food samples were acquired from family meals each day. They represented a one-third portion of each meal eaten at home. The range of BaP per gram of wet weight of food was between 0.004 and 1.2 ng/g. Of the 20 wk of exposure (10 x 2 wk), 10 had higher food exposures and the other 10 had higher inhalation exposures. Of the two groups, the higher food exposures usually had a greater number of ng of BaP/wk. The dominance of one or the other pathway appeared to depend upon personal eating habits and indoor combustion source use. In some instances, outdoor air pollution led to a major portion of indoor air BaP exposures. Water appears to be a minor source of BaP exposures in the study area.     

Levels of airborne dust by particle size in a suburb of Takamatsu,Japan

PURPOSE: In recent years, attention has been paid to the influence of the particle fraction < or = 2.5 microns in diameter (PM2.5) among suspended particulate matter (SPM) on health. However, the present status of particle contamination in Japan has hitherto not been adequately clarified. To determine particle contamination in the outdoor air around Kagawa Medical School located on a hill in the suburb of Takamatsu City, we measured SPM according to diameter between February 1999 and January 2000. METHODS: Mass concentrations of SPM were determined using an Andersen air sampler and light scattering counts were measured using a particle counter at the same site. RESULTS: Of the entire year, the total SPM concentration (PM11) was 20-30 mg/m3, and the particle fraction < or = 2.1 microns in diameter (PM2.1) accounted for 25-60%. Both the PM11 and PM2.1 concentrations were the lowest in August when the wind blew mainly from rural areas, but high in January and February when the wind blew mainly from urban areas and April when yellow sand was wind borne from China. The SPM particle count in April was markedly high when a misty aerosol containing yellow sand was extent. The SPM count for each diameter class rapidly decreased after rainfall during passage of storm fronts, but this was especially marked for smaller diameters. During the measurement period in August, air from rural areas often passed the measurement point, and the particle concentration < or = 1 micron in diameter was markedly lower than that in April. CONCLUSION: The results suggest that the SPM levels around Kagawa Medical School located in the suburb of Takamatsu City are associated with seasonal climate and the wind direction from which the prevailing blew.     

Air pollution survey in Kitakyushu district

Airborne particulate samples were collected on a glass fiber filter or quartz filter using Hi-volume air sampler from November, 1980 through February, 1983 at a west part of Yahata district, Japan. The concentrations of airborne particulates, polynuclear aromatic hydrocarbons (PAH), heavy metals and dustfall were determined, and mutagenic activities of tarry materials obtained from suspended particulates were also measured. The following results were obtained. (1) The airborne particulate contents were 22.1 - 188 mg/1000 m3 (mean : 74.6 mg/1000 m3), and the values were high in spring and low in summer. (2) PAH contents in airborne particulates were in the following order: benzo(ghi)perylene greater than benzo(a)pyrene greater than benz(a)anthracene greater than chrysene greater than benzo(k)fluoranthene greater than pyrene greater than perylene. PAH contents were higher in winter that in summer. The benzo(a)pyrene contents were 1.97 micrograms/1000 m3 in 1981 and 1.92 micrograms/1000 m3 in 1982. (3) Heavy metals content was about 2.1 - 3.6 higher in winter in comparison with that in summer time. (4) Mutagenic activity showed 90 - 11900 revertants/1000 m3 for TA 98 strain with S-9 mix and 50 - 7190 revertants/1000 m3 for TA 98 strain without S-9 mix. Mutagenic activities for TA 98 with S-9 mix were higher than those for TA 98 without S-9 mix. (5) As a result of the analysis of airborne particulate samples, a significant correlation was observed between mutagenic activities and the concentrations of PAH and heavy metals. These results indicated that the mutagenic survey may be useful as an index for air pollution study.     

Association of indoor and outdoor air pollutant level with respiratory problems among children in an industrial area of Delhi, India

The authors conducted this prospective study at the Shahdara industrial area of Delhi, India. They examined the effects of indoor and outdoor air pollutant levels on respiratory health in 394 children aged 7 to 15 years. The majority of children had a history of respiratory problems, including cough (62.7%), sputum production (24.4%), shortness of breath (32.0%), wheezing (25.6%), common cold (44.4%), and throat congestion (43.1%). The association of indoor and outdoor air pollutant levels showed that outdoor SO2 and NO2 was significantly higher than indoor SO2 and NO2 levels, whereas the mean indoor level of suspended particulate matter (SPM) was significantly higher than outdoor SPM level. Indoor SPM level also was significantly higher in homes of children with a history of respiratory illness than homes of children having no history of respiratory illness. Results suggest that both indoor and outdoor particulate exposure may be important risk factors in the development of respiratory illness in children.     

Volumetric assessment of airborne indoor and outdoor fungi at poultry and cattle houses in the Mazandaran Province, Iran

The aim of this study was to assess the volume of airborne fungi in the indoor and outdoor environment of poultry and cattle houses in the Mazandaran Province in Iran. Indoor and outdoor air of twenty cattle houses and twenty-five poultry houses were sampled using a single-stage impactor, which draws air at 20 L min-1 and impacts sampled material onto Petri plates containing malt extract agar. The plates were incubated at 30 °C for seven days, after which the resulting colonies were counted. The fungi were identified and counted microscopically and macroscopically. A total of 4,662 fungal colonies were isolated from 90 plates collected from indoor and outdoor air of cattle and poultry houses. Cladosporium (55.3 %), yeast (10.0 %), and Aspergillus (9.4 %) were the most common findings. The concentration of airborne fungi in cattle and poultry houses ranged from 10 CFU m-3 to 1700 CFU m-3 in indoor and 10 CFU m-3 to 2170 CFU m-3 in outdoor environments. Cladosporium had the highest mean indoor (424.5 CFU m-3) and outdoor (449.7 CFU m-3) air concentration in the cattle houses. In the poultry houses, the highest mean concentrations were measured for Cladosporium (551.0 CFU m-3) outdoors and yeast (440.7 CFU m-3) indoors. These levels might present an occupational risk, but threshold levels for these environments have yet to be established worldwide.     

Performance evaluation of continuous air monitor (CAM) sampling heads

Continuous air monitor (CAM) samplers are used to detect radioactive aerosol particles in nuclear facilities and to provide alarm signals should the concentrations exceed a multiple of the derived air concentration (DAC) of the radionuclide of concern in a set amount of time. Aerosol particles are drawn into a CAM sampler where collection is to take place upon a filter. Radioactivity of the particles is determined with a detector that is placed in close proximity to the filter face. An important determinant of CAM performance is the ability of the inlet and body of the CAM to transport particulate matter in the inhalable-size range (less than or equal to 10 microns aerodynamic diameter) to the filter without substantial loss or bias with respect to particulate size. Three types of CAM samplers were tested in a low-velocity aerosol wind tunnel to determine the degree to which particles penetrate through the flow systems to the collection filter under conditions typical of normal room air exchange rates. Two air velocities were used: 0.3 and 1.0 m s-1. The CAM samplers were primarily operated at a flow rate of 56.6 L min-1, although some tests were conducted at a flow rate of 28.3 L min-1. The CAM units were prototypes manufactured by Kurz Instruments, Eberline Instrument Corporation, and Victoreen Inc. These three units represent three different approaches to CAM head design. At an air speed of 1 m s-1, aerosol penetration to the filters of the Kurz unit was essentially 100% for particle sizes of 3 and 7-microns aerodynamic diameter and was 86% for a size of 15 microns. For the Eberline sampler, the penetration was over 80% for 3-microns particles but was reduced to less than 2% for 7-microns particles. The victoreen sampler showed penetration values of 98% for 3-microns aerodynamic diameter particles, 88% for 7-microns particles and 4% for a size of 15 microns. Air speed had little effect on the penetration results for the two speeds which were tested. Tests were conducted to determine the uniformity of deposits on the filters of the CAM samplers. For a particle size of 10 microns, the deposits were nonuniform for all three of the instruments.     

Concentration, Origin and Health Hazard from Fine Particle-Bound PAH at Three Characteristic Sites in Southern Poland

Suspended particles with the aerodynamic diameters not greater than 2.5 μm (PM_2.5) and 1 μm (PM₁, sub-fraction of PM_2.5) were sampled at three sites: an urban background site, rural background site, and urban traffic site in southern Poland. In total, there were 240 samples taken within 02.08.2009–27.12.2010. Fifteen polycyclic aromatic hydrocarbons (PAH) were determined in each dust fraction. The averages of the concentration of total PAH (ΣPAH) and of particular PAH, as well as the share of carcinogenic PAH in total PAH (ΣPAH_carc/ΣPAH), carcinogenic equivalent, mutagenic equivalent, and TCDD-toxic equivalent appeared high compared to other areas in the world. Their high values express the significance of health hazard from PM and PM-bound PAH in southern Poland. The diagnostic ratios suggest that PM-bound PAH originate from municipal (PM_1?2.5) and vehicular (PM₁) combustion.