Inhalation exposure of traffic police officers to polycyclic aromatic hydrocarbons (PAHs) during the winter in Beijing, China

This study concerns the use of personal samplers to evaluate the exposure of traffic police to polycyclic aromatic hydrocarbons (PAHs) during the winter of 2005 in Beijing. We measured the samples collected for gas and particulate phases PAHs with the same technique used for an earlier study during the summer of 2004, and evaluated exposure risk based on the calculated benzo(a)pyrene equivalent concentrations (BaP(eq)) of both summer and winter. The mean exposure concentrations of gaseous and particulate phase PAHs in the winter are 4300+/-2900 ng/m(3) and 750+/-1000 ng/m(3), respectively, significantly higher than those measured simultaneously at control sites and also considerably higher than the values measured during the summer. The exposure PAH profiles for police and the control subjects are similar with predominant naphthalene in gaseous phase and dominant fluoranthene, pyrene, anthracene and naphthalene in particulate phase. Large daily variations occur both in summer and winter, because of the changes in the weather conditions especially wind speed and relative humidity which tend to disperse and scavenge PAHs in air. In the winter, the average BaP(eq) value for traffic police is 82.1 ng/m(3), which is significantly higher than those for the control subjects and the national standard of 10 ng/m(3) for ambient air. Particulate phase PAHs contribute more than 90% of the total exposure risk in the winter. Annually, weighted-average probabilities of exceeding the national standard (10 ng/m(3)) are 69.3% and 20.6% for the police and the controls, respectively.     

The exposure of temple workers to polycyclic aromatic hydrocarbons

Five temples, each a different size, were selected for this study. Two of the temples were located in Taichung City (in central Taiwan), and three were in Tainan City (in Southern Taiwan). Aerosols smaller than 10 microm aerodynamic diameter (PM(10)) were collected by using personal collection samplers during pilgrim days (the first and fifteenth day of each lunar month) and normal days (all other days). Regression analysis showed that about 1.6 microg/m(3) of PM(10) contributed to the workers' exposure in the temples for each joss stick increase in the censer. The concentrations of total polycyclic aromatic hydrocarbons (t-PAHs) and carcinogenic PAHs (car-PAHs) on pilgrim days were higher than those on normal days. Mean concentrations of urinary 1-hydroxypyrene (1-OHP) in the pre-shift and post-shift workers of the five temples on normal days were 1.20 and 1.61 microg/g creatinine, respectively. Furthermore, the post-shift concentrations of 1-OHP in the workers of temples on pilgrim days were all higher than those of the workers of corresponding temples on normal days. Significant relationships between the urinary concentrations of 1-OHP and the exposure concentrations of pyrene, total PAHs and BaP(eq) were found in the workers of the temples. Results of linear regression showed that the increase of unit concentration (1 ng/m(3)) of pyrene led to a 0.05 microg/g creatinine increase of urinary 1-OHP, while the increase of unit concentration (1 ng/m(3)) of BaP(eq) resulted in an increase of 0.03 microg/g creatinine of urinary 1-OHP.     

太原市冬季PM2.5中多环芳烃、硝基多环芳烃、SO4^2-和NO3^-的污染特征

以太原市2013年冬季大气细颗粒物（PM2.5）为研究对象,定性与定量分析了其中多环芳烃（PAHs）、硝基多环芳烃（NPAHs）、硫酸盐（SO4^2-）和硝酸盐（NO3^-）的浓度及其昼夜变化。采用特征比值法分析了PAHs、SO4^2-和NO3^-的来源,并通过PEFs毒性评价法评价了PM2．5中PAHs的BaP等效毒性,估算出个体致癌指数。结果显示,太原市PM：,中16种PAHS总含量、3种NPAHs总含量及SO4^2-和NO3^-含量分别在102—153ng／m^3、0．41—0．镐ng／rnj、4．89—5．87o,g／m^3和1．69—1．71p,g／m。范围内,且其夜间浓度均高于白天。PAHs的BaP等效毒性和个体致癌指数超过标准值。结果提示,太原市PM25中PAHs、NPAHs、SO4^2-和NO3^-污染主要是由于燃料燃烧和固定源引起的,且颗粒物上的PAHs浓度高,对人体健康有潜在的风险。     

Emission of polycyclic aromatic hydrocarbons and lead during Chinese mid-autumn festival

The emission factors of total particulate polycyclic aromatic hydrocarbons (PAHs), Benzo(a)pyrene (BaP), BaP-equivalent doses (BaP(eq)) and Pb for burning three kinds of charcoal were investigated in this study: fast-lighting charcoal, Taiwanese, and Indonesian charcoal (the latter two of which are not fast-lighting). Compared to the burning of Taiwanese and Indonesian charcoal, the burning of fast-lighting charcoal can emit much larger amounts of total PAHs, BaP(eq) and Pb into the atmosphere. The emission factors of total PAHs, BaP and BaP(eq) for broiling meat were noticeably higher than those for broiling vegetables and non-fish seafood. When using Indonesian charcoal to broil meat, the total emission factors of particulate PAHs and BaP were about 15.7 and 0.39 mg/kg, respectively. The total amounts of particulate PAHs and Pb emitted from cookouts during Mid-Autumn Festival were 2881 and 120 g, respectively. Total PAHs and BaP(eq) in PM(10) aerosols on Mid-Autumn Festival nights increased about 1.6 and 1.5 times, respectively, higher than those on non-festival nights. The mean concentration of Pb on the nights of Mid-Autumn Festival increases to about 2.8 times that of non-festival nights.     

Polycyclic aromatic hydrocarbons inside and outside of apartments in an urban area

In the context of environmental monitoring in Berlin polycyclic aromatic hydrocarbon (PAH) concentrations in air and household dust were measured inside 123 residences (and simultaneously in a sub group in the air outside the windows). The aim of this study was to determine exposure to PAHs in the environment influencing by several factors, for instance, motor vehicle traffic in a populous urban area. Indoor air samplings were carried out in two periods (winter and spring/summer) in smokers and non-smokers apartments. Benzo(a)pyrene (BaP) median values were 0.65 ng m(-3) (winter) and 0.27 ng m(-3) (spring/summer) in smokers' apartments and 0.25 ng m(-3) (winter) and 0.09 ng m(-3) (spring/summer) in the apartments of non-smokers. The median BaP content in ambient air was 0.10 ng m(-3) (maximum: 1.1 ng/m(-3)) with an indoor-outdoor mean concentration ratio of 0.9 in non-smoker households and 5.4 in smoker apartments. In household dust we obtained median values of 0.3 mg kg(-1) (range: 0.1-1.4 mg kg(-1)). We found a significant relation between indoor and outdoor values. Approximately 75% of the variance of indoor air values was caused by the corresponding BaP concentrations in the air outside the apartment windows. Otherwise a significant correlation between indoor air and household dust values cannot be found. Therefore, according to our results, it is suggested that the indoor PAH concentration in non-smoker apartments could be attributed mainly to vehicular emissions.     

Performance evaluation of air quality models for predicting PM10 and PM2.5 concentrations at urban traffic intersection during winter period

There are several models that can be used to evaluate roadside air quality. The comparison of the operational performance of different models pertinent to local conditions is desirable so that the model that performs best can be identified. Three air quality models, namely the 'modified General Finite Line Source Model' (M-GFLSM) of particulates, the 'California Line Source' (CALINE3) model, and the 'California Line Source for Queuing & Hot Spot Calculations' (CAL3QHC) model have been identified for evaluating the air quality at one of the busiest traffic intersections in the city of Guwahati. These models have been evaluated statistically with the vehicle-derived airborne particulate mass emissions in two sizes, i.e. PM10 and PM2.5, the prevailing meteorology and the temporal distribution of the measured daily average PM10 and PM2.5 concentrations in wintertime. The study has shown that the CAL3QHC model would make better predictions compared to other models for varied meteorology and traffic conditions. The detailed study reveals that the agreements between the measured and the modeled PM10 and PM2.5 concentrations have been reasonably good for CALINE3 and CAL3QHC models. Further detailed analysis shows that the CAL3QHC model performed well compared to the CALINE3. The monthly performance measures have also led to the similar results. These two models have also outperformed for a class of wind speed velocities except for low winds (<1 m s(-1)), for which, the M-GFLSM model has shown the tendency of better performance for PM10. Nevertheless, the CAL3QHC model has outperformed for both the particulate sizes and for all the wind classes, which therefore can be optional for air quality assessment at urban traffic intersections.     

Particle-associated polycyclic aromatic hydrocarbons in the atmospheric environment of Zonguldak, Turkey

Airborne fine (PM(2.5)) and coarse (PM(2.5-10)) particulate matter was collected from January to December in 2007 in Zonguldak, Turkey using dichotomous Partisol 2025 sampler. Fourteen selected polycyclic aromatic hydrocarbons (PAHs) in particulate matter were determined simultaneously by high-performance liquid chromatography with fluorescence detection (HPLC-FL) and seasonal distributions were examined. The source identification of PAHs in airborne particulates was performed by principal component analysis (PCA) in combination with diagnostic ratios. The predominant PAHs determined in PM(2.5) were pyrene, fluoranthene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene. The total concentrations of PAHs were up to 464.0 ng m(-3) in fine and 28.0 ng m(-3) in coarse fraction in winter, whereas in summer times were up to 22.9 and 3.0 ng m(-3) respectively. Approximately 93.3% of total PAHs concentration was determined in PM(2.5) in winter and 84.0% in summer. The concentration levels of PAHs fluctuate significantly within a year with higher means and peak concentrations in the winter compared to that of summer times. Higher benzo(a)pyrene-equivalent (BaPE) concentrations of PAHs were obtained for PM(2.5) especially in winter. The results obtained from PCA in combination with diagnostic ratios revealed that coal combustion and vehicle emissions were the major pollutant sources for both PM(2.5) and PM(2.5-10) associated PAHs in studied area. Two principal components for PM(2.5) and three for PM(2.5-10) were identified and these accounted for 89.4 and 85.2% of the total variance respectively. The emissions from coal combustion were estimated to be the main source of PAHs in the ambient air particulates with contributions of 80.8% of total variance for PM(2.5) and 53.8% for PM(2.5-10).     

Comparisons of commuter's exposure to particulate matters while using different transportation modes

This study compared commuters' exposures to particulate matter (PM) while using motorcycles, cars, buses, and the mass rapid transit (MRT) on the same routes in Taipei, Taiwan. Motorcycle commuters who had the shortest travel time (28.4+/-4.2 min) were exposed to the highest concentrations of PM(10) (112.8+/-38.3 microg/m(3)), PM(2.5) (67.5+/-31.3 microg/m(3)), and PM(1.0) (48.4+/-24.7 microg/m(3)) among four commuting modes. By contrast, car commuters were exposed to the lowest PM concentrations and had the second shortest travel time among them. Motorcycle commuters' high trip-averaged PM concentrations and bus commuters' long commuting time (43.1+/-5.1 min) resulted in their high whole-trip PM exposures. Size fractions of PM were relatively consistent across PM exposures of the four commuting modes with fine particles (PM(2.5)) contributing to 53-60% of PM(10) and submicron particle (PM(1)) contributing to 39-43% of PM(10). Motorcycles idled at traffic lights and bus doors opened at stops increased commuters' PM exposures. Fixed-site monitoring data explained well the variation of whole-trip PM(10) exposure of car (r(2)=0.63) and MRT (r(2)=0.52) commuters, and of whole-trip PM(2.5) exposure of car (r(2)=0.76), MRT (r(2)=0.73) and motorcycle (r(2)=0.64) commuters in regression analyses. The coefficients (slopes) of regression between fixed-site monitoring data and PM(2.5) exposures were less than 1 for car and MRT commuters but greater than 1 for motorcycle commuters. In conclusion, proximity to traffic emissions contributes to a person's high PM exposure during his or her daily commute. This proximity occurs when people use motorcycles on roads and when bus/MRT commuters walk or wait along commuting routes. Fixed-site air monitoring data can under-estimate motorcycle commuters' PM(2.5) exposures but over-estimate car and MRT commuters' PM(2.5) exposures.     

Mutagenicity and polycyclic aromatic hydrocarbons analysis of ambient airborne particles collected in Athens, Greece

Samples of airborne particulates from the Athens atmosphere were examined for mutagenicity and various polycyclic aromatic hydrocarbons (PAH). Extracts induced linear, dose-related increases in TA98 His+ revertants in the Ames/Salmonella assay and contained average benzo[a]pyrene (BaP) levels of 3.9 ng/m3 of air. The levels of revertants/m3 of the samples showed a linear relation to their BaP and benzo[b]-(BbF) + benzo[k]-fluoranthene (BkF) concentrations and were higher in areas with dense traffic than in industrial areas. It is suggested that the atmosphere of Athens favours the formation of secondary direct-acting mutagens due to the oxidation and nitration of PAH by ozone and nitrogen oxides, which are more abundant in the late spring months.     

Personal daily exposures to benzo(a)pyrene of taxi drivers in Genoa, Italy

Twenty-four hour personal exposures (both occupational and environmental) to benzo(a)pyrene (BaP) of 15 taxi drivers working in Genoa, Italy, were monitored in May-July 1998 (15 samplings), February 1999 (7 samplings) and June 1999 (7 samplings). The mean BaP exposures measured at these different times were 1.4 ng/m3, 1.23 ng/m3 and 1.22 ng/m3, respectively, values were significantly greater than the levels found in controls (0.16+/-0.2 ng/m3). Mean daily personal BaP exposures of taxi drivers were not statistically different from the mean daily airborne BaP concentrations measured by fixed samplers during the same sampling periods.     

Particulate matter exposure along designated bicycle routes in Vancouver, British Columbia

An instrumented bicycle was used to elucidate particulate matter exposures along bicycle routes passing through a variety of land uses over 14 days during summer and fall in a mid-latitude traffic dominated urban setting. Overall, exposures were low or comparable to those found in studies elsewhere (mean PM(2.5) and PM(10) concentrations over each daily bicycle traverse varied between 7-34 microg m(-3) and 26-77 microg m(-3) respectively). Meteorological factors were responsible for significant day-to-day variability with PM(2.5) positively correlated with air temperature, PM(10) negatively correlated with precipitation, and ultrafine particles negatively correlated with both air temperature and wind speed. On individual days, land use and proximity to traffic were factors significantly affecting exposure along designated bicycle routes. While concentrations of PM(2.5) were found to be relatively spatially uniform over the length of the study route, PM(10) showed a more heterogeneous spatial distribution. Specifically, construction sites and areas susceptible to the suspension of road dust have higher concentrations of coarse particles. Ultrafine particles were also heterogeneously distributed in space, with areas with heavy traffic volumes having the highest concentrations. Observations show qualitative agreement in terms of spatial patterns with a land-use regression (LUR) model for annual PM(2.5) concentrations.     

2,3,7,8-TCDD equivalence and mutagenic activity associated with PM10 from three urban locations in New Zealand

Ambient particulate matter (PM(10)) in urban centres varies depending on emission sources, geography, demography, and meteorology. Hence physical (PM(10), wind speed, rainfall, temperature), chemical (polycyclic aromatic hydrocarbons, PAH), and toxicological (Ames Test, H4IIE EROD Assay) analyses were done on daily PM(10) (approximately 1640 m(3)/day) collected from three New Zealand urban sites where winter emissions were predominantly due to domestic home heating. Daily PM(10) levels ranged between 9.7 and 20.8 in summer and between 21.8 and 61.0 microg/m(3) in winter. Daily PAH concentrations were 0.5, 0.45, and 1.5 ng/m(3) in summer and 52.1, 128.9, and 5.8 ng/m(3) in winter at sites Christchurch, Alexandra and Dunedin, respectively. During winter, 74% of PM(10) extracts from all three sites showed significant mutagenicity in the Ames Test (TA 98, -S9), whereas approximately 25% of the daily PM(10) was mutagenic in summer. Benzo[a]pyrene and BaP carcinogenic equivalence concentrations during winter were strongly correlated to both mutagenicity and TCDD-like activity at two sites. Daily levels of TCDD toxicity equivalence concentrations ranged from 0.5 to 3.6 pg TCDD/m(3) air in summer and from 0.3 to 4009 pg TCDD/m(3) air in winter. Chemically and biologically derived TCDD toxicity equivalent concentrations were significantly correlated in all study locations indicating that PAH may represent most of the TCDD-like activity present in the PM(10).     

Emission of polycyclic aromatic hydrocarbons from animal carcass incinerators

This study investigated two batch-type animal carcass waste incinerators, one in a hog farm (HOWI) and the other in a livestock disease control centre (LIWI). Additionally, a medical waste incinerator (MEWI) with a fixed grate for the disposal of biological medical waste was also examined. A GC/MS technique was applied to analyze the concentrations of 21 polycyclic aromatic hydrocarbons (PAHs) species in the stack flue gas, bottom ash and wet scrubber (WSB) effluent. The analytical results indicated that total-PAHs in the stack flue gas for HOWI, LIWI and MEWI were mainly in the gaseous phase. Moreover, the mean total-PAHs concentrations of the stack flue gas for HOWI and LIWI were 1.5 and 1.4 times higher than for MEWI (=391 microg/m(3)), respectively. At the most carcinogenic potencies, the results revealed that the mean BaP+BbF+DBA concentrations in the stack flue gas for HOWI and LIWI were 7.6 and 4.6 times higher than those of MEWI (=1.18 microg/m(3)), respectively. Moreover, during the outbreak of foot-and-mouth disease among pigs in southern Taiwan in 1997, emissions of total-PAHs and BaP+BbF+DBA exceeded 226.2 and 2.3 kg/day, respectively.     

Biomonitoring of benzene and 1,3-butadiene exposure and early biological effects in traffic policemen

The objective of this study was to determine benzene and 1,3-butadiene exposure through ambient air and personal air monitoring, as well as through biomarkers of exposure, and to evaluate the potential health risk of exposure through the use of biomarkers of early biological effects in central Bangkok traffic policemen. Ambient air concentrations of benzene and 1,3-butadiene at the roadsides were significantly higher than in police offices used as control sites (p < 0.001). Traffic policemen had a significantly higher exposure to benzene (median 38.62 μg/m³) and 1,3-butadiene (median 3.08 μg/m³) than office policemen (median 6.17 μg/m³ for benzene and 0.37 μg/m³ for 1,3-butadiene) (p < 0.001). Biomarkers of benzene exposure, blood benzene, and urinary metabolite, trans, trans-muconic acid were significantly higher in traffic policemen than office policemen (p < 0.001). No significant difference between traffic and office policemen was found in urinary benzene metabolite, S-phenyl mercapturic acid, or in urinary 1,3-butadiene metabolite, monohydroxy-butenyl mercapturic acid. Biomarkers of early biological effects, 8-hydroxy-2′-deoxyguanosine in leukocytes (8-OHdG), DNA-strand breaks, and DNA-repair capacity, measured as an increase in gamma ray-induced chromosome aberrations were significantly higher in traffic policemen than controls (p < 0.001 for 8-OHdG, p < 0.01 for tail length, p < 0.001 for olive tail moment, p < 0.05 for dicentrics and p < 0.01 for deletions). Multiple regression model including individual exposure, biomarkers of exposure, ages and years of work as independent variables showed that only the levels of individual 1,3-butadiene exposure were significantly associated with 8-OHdG and olive tail moment at p < 0.0001 indicating more influence of 1,3-butadiene on DNA damage. These results indicated that traffic policemen, who are exposed to benzene and 1,3-butadiene at the roadside in central Bangkok, are potentially at a higher risk for development of diseases such as cancer than office policemen.     

Exposure to genotoxins present in ambient air in Bangkok, Thailand--particle associated polycyclic aromatic hydrocarbons and biomarkers

Exposure to genotoxic compounds in ambient air has been studied in Bangkok, Thailand, by analysis of polycyclic aromatic hydrocarbons (PAHs) associated with particles and using different biomarkers of exposure. Eighty-nine male, non-smoking Royal Thai police officers were investigated. The police officers were divided into a high exposure group (traffic police) and low exposure (office duty). Particulate matter was collected using personal pumps (2 l/min) and the eight carcinogenic PAHs were analysed by standard procedures. The traffic police was exposed to a 20-fold higher level of total PAHs than office police (74.25 ng/m3 vs. 3.11; P= 0.001). A two-fold variation was observed between the different police stations. The major PAHs in all groups was benzo[g,h,l]pyrelene. Large inter-individual differences in biomarker levels were observed, but the level of all markers was statistically significantly higher in the traffic police group than in the office group. The level of 1-hydroxypyrene (1-HOP) was 0.181+/-0.078 (range 0.071-0.393) micromol/mol creatinine in the traffic group and 0.173+/-0.151 (P = 0.044) in the office group. The bulky carcinogen DNA-adduct level, determined by P32-post-labelling, was 1.6+/-0.9 (range 0.4-4.3) adducts/10(8) nucleotides in the traffic group and 1.2+/-1.0 (0.2-4.9) in the office group (P = 0.029; Mann-Whitney U-test). The serum PAH-albumin adduct level was 1.76 (0.51-3.07) fmol adducts/microg albumin in the traffic group and 1.35+/-0.77 (0.11-3.45; P = 0.001) in the office group. Lower biomarker levels were observed during the period when the traffic police officers were wearing a simple facemask, indicating that these masks protect against particle-associated PAHs. No statistically significant correlations were observed between biomarker levels and the level of individual PAHs or total PAH. Our data show, that people in Bangkok, who spend most of the day outside air-conditioned offices, are exposed to high levels of genotoxic PAHs. However, for people who spend their working day in offices, the exposure is similar to people living in other metropolitan areas.     

Traffic emission scenarios in Lombardy region in 1998-2015

This study assesses and discusses the current and future contribution of road traffic to primary PM10 and PM10 main precursors (i.e. NO(x), SO(2), NH(3), VOC) in the Lombardy region (Italy). It defines a coherent and updated set of input parameters (emission factors, mileage and fleet composition) for traffic emission estimation between 1998 and 2015. 1998-2004 emissions are assessed basing on historical data, while 2005-2015 rely on different hypothesis about mobility development and vehicular turnover rate. The work shows that road traffic emissions of PM10 and PM10 precursors are expected to decrease in the period 2005-2015, with a reduction greater than 70% in scenarios with a fast vehicle turnover and a decrease in fuel usage. Increase in fuel consumption could substantially lower the emission reduction expected, off-setting a substantial part of the new technology benefits. The introduction of DPF (diesel particulate filter) vehicles will determine a reduction of PM10 exhaust, however this could potentially be stalled by the increase in diesel usage in the vehicle fleet and an increase in mileage driven, as the latter causes a rise in the contribution of PM10 from abrasion. Concerning the total atmospheric emissions in Lombardy, SO(2) (-6%) and NH(3) (<-2%) emission will remain constant, while PM10, VOC and NO(x) emission will decrease, respectively by 2-30%, 6-15% and 2-32% in the period 2001-2015.     

Heavy incense burning in temples promotes exposure risk from airborne PMs and carcinogenic PAHs

We present the mechanistic-based exposure and risk models, appraised with reported empirical data, to assess how the human exposure to airborne particulate matters (PMs) and carcinogenic polycyclic aromatic hydrocarbons (PAHs) during heavy incense burning episodes in temples. The models integrate size-dependent PM levels inside a temple from a published exploratory study associated with a human expiratory tract (HRT) model taking into account the personal exposure levels and size distributions in the HRT. The probabilistic exposure profiles of total-PAH levels inside a temple and internal PAHs doses are characterized by a physiologically based pharmacokinetic (PBPK) model with the reconstructed dose-response relationships based on an empirical three-parameter Hill equation model, describing PAHs toxicity for DNA adducts formation and lung tumor incidence responses in human white blood cells and lung. Results show that the alveolar-interstitial (AI) region has a lower mass median diameter (0.29 microm) than that in extrathoracic (ET(1), 0.37 microm), brochial (BB, 0.36 microm) and bronchiolar (bb, 0.32 microm) regions. The 50% probability (risk=0.5) of exceeding the DNA adducts frequency (DA(f)) ratio of 1.28 (95% CI: 0.55-2.40) and 1.78 (95% CI: 0.84-2.95) for external exposure of B[a]P and B[a]P(eq), respectively. The 10% (risk=0.1) probability or more of human affected by lung tumor is approximately 7.62x10(-5)% (95% CI: 3.39x10(-5)-1.71x10(-4)%) and 3.87x10(-4)% (95% CI: 1.72x10(-4)-8.69x10(-4)%) for internal exposure of B[a]P and B[a]P(eq), respectively. Our results implicate that exposure to smoke emitted from heavy incense burning may promote lung cancer risk. Our study provides a quantitative basis for objective risk prediction of heavy incense burning exposure in temples and for evaluating the effectiveness of management.     

Extractable organic matter in PM10 from LiWan district of Guangzhou City,PR China

PM10 (particulate matter with aerodynamic diameter <10 microm) samples were collected at LiWan District of Guangzhou, PR China during April and July 2001 using a high volume air sampler to determine the distributions of homologous compounds and biomarkers. Polycyclic aromatic hydrocarbons (PAHs) including non-alkylated PAHs, methyl-alkylated PAHs, and some PAHs containing S/O atoms and n-alkanes were measured using gas chromatography/mass spectrometry analysis. The sigma(n)-alkane and sigmaPAHs ranged from 26.4 to 719.2 ng/m3 and 7.4 to 159.4 ng/m3, respectively. A seasonal fluctuation was clearly evident with higher concentrations occurring during the colder months (April). In addition, some compositional differences are observed for the organic compounds in samples collected from different heights above ground level. Higher sites had a significant contribution from vascular plant wax. The presence of petroleum products with no carbon number preference, pristane, phytane and a significant unresolved complex mixture (UCM) with unresolved to resolved components ratio (U/R) of 6.2-13.2 confirm the petroleum component. The relative distribution of n-alkanes and the values of molecular diagnostic ratio, such as carbon preference index (CPI) values ranging from 1.0 to 1.4 (for the whole range of n-alkanes), indicated the importance of petroleum and diesel residues and gasoline emissions, as well as the minor contribution of n-alkanes emitted directly from epicuticular waxes. Indeed, the percent contribution of leaf 'wax' n-alkanes (5.2-19.4%) indicated a low contribution of biogenic sources. The fossil fuel biomarkers, hopanes and steranes were observed in the PM10 samples, which indicate a petroleum origin. The distribution pattern of PAHs was characteristic of anthropogenic emissions. Coupling carbon number maximum (Cmax), CPI, U/R values, molecular marker and molecular diagnostic ratios for alkanes and PAHs revealed a classification of natural biogenic and anthropogenic components of atmospheric aerosols. These analyses support the conclusion that vehicular emission was the major source of organic compounds during the study period, while the contribution of epicuticular waxes emitted by terrestrial plants was minor.     

浅析同济大学校园交通

以同济大学校园交通规划为例,分析了其道路网、道路分级和道路使用情况,从动态交通和静态交通两方面论述了同济大学的校园道路交通组织现状,提出了相应的解决措施,从而使同济大学校园交通规划满足规范要求。     

基于AHP的城市道路交通通行效率影响模型研究

为了对城市道路交通通行的效率做出客观评价,对影响交通通行效率的因素进行了研究。首先分别从道路和交通条件中识别对交通通行效率的影响要素,并对其重要程度进行分析,运用AHP分别建立城市道路交叉口和路段的交通通行效率影响的分析模型;然后根据苏州市马环线实地调查数据对其通行效率的影响进行了定量分析。该研究成果可为道路交通改善设计方案提供支撑。