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Deep excavations are intensively carried out in many cities in China and other countries. One of the major loadings in such construction work is the water pressure, and great effort is required to assess the seepage problem and the corresponding water pressure on the retaining wall for a good design and construction. Different methods used for the seepage analysis are discussed in this paper through a series of projects in Hong Kong. Some interesting phenomena from the seepage analysis will also be discussed. Two large scale seepage field tests in Hong Kong are also used for the illustration of the back analysis in seepage problems which are seldom carried out. The comparative studies demonstrate that a realistic seepage analysis is very important for deep excavation works, but it was not seriously considered in the past. [ABSTRACT FROM AUTHOR]

Objective: To examine preferences for follow-up testing in women screened with high or intermediate risk for Down syndrome in the first or second trimester.Design: Prospective cohort study.Setting: Three public hospitals in Hong Kong, China.Sample: Women with pregnancies termed as high risk (≥1:250; HR) or intermediate risk (1:251-1200; IR) for Down syndrome.Methods: Women with pregnancies screened as HR were offered the choices of: (1) an invasive test plus chromosomal microarray (CMA) to obtain more detailed fetal genetic information; (2) non-invasive cell-free prenatal DNA screening (NIPT) to detect trisomies 13, 18 and 21, and to avoid procedure-related miscarriage; and (3) to decline any further testing. Women received standardised counselling informing them that the reporting times were identical, the procedure miscarriage risk was 0.1-0.2% and that there was no charge for screening. Women with IR pregnancies (1:251-1200) were offered NIPT as a secondary screening test.Main Outcome Measures: Uptake rate for NIPT.Results: Three hundred and forty-seven women had pregnancies deemed as HR; 344 (99.1%) women opted for follow-up testing, 216 (62.2%) of whom chose NIPT. Five hundred and seven of 614 women (82.6%) with IR risk chose NIPT. Seven (21%) of 34 women with nuchal translucency ≥3.5 mm opted for NIPT.Conclusion: In a setting where reporting times are similar and there is no cost difference between options, approximately 60% of women with pregnancies classed as HR would opt for NIPT, offering simple but limited aneuploidy assessment, over a diagnostic procedure with comprehensive and more detailed assessment.Tweetable Abstract: 60% of pregnant Chinese women prefer NIPT over CMA when screened as high risk for Down syndrome. [ABSTRACT FROM AUTHOR]

Objective: To assess the potential of screening for pre-eclampsia (PE) in a Chinese population.Design: Case-control study.Setting: Teaching hospital in Hong Kong.Population: A total of 3330 women having a viable singleton pregnancy attending first-trimester Down-syndrome screening.Methods: Mean arterial pressure (MAP), bilateral uterine artery pulsatility index (UtA-PI), and placental growth factor (PlGF) were measured. Screening markers were transformed to multiples of the gestational median (MoM) and adjusted for maternal and pregnancy characteristics. MoM distributions in PE and non-PE pregnancies were compared with published expected values. PE screening performance was assessed using area under receiver operating curves (AUROC).Main Outcome Measures: PE detection rate.Results: A total of 30 (0.9%) women developed either early (<34 weeks) or late (≥34 weeks) onset PE. MAP was dependent on maternal BMI, UtA-PI on fetal crown rump length, uterine artery peak systolic velocity (UtA-PSV) on maternal age and gestation, and PlGF on gestation in non-PE pregnancies. MoM distributions determined using published Fetal Medicine Foundation models deviated significantly from one for both MAP (P < 0.0001) and PI (P < 0.0001), but not PlGF (P = 0.52) in non-PE pregnancies, whilst PlGF MoM distributions in those who developed early as opposed to late onset PE were significantly higher (P = <0.05). AUROC for any PE using multiple markers was 0.72 (95% CI: 0.64-0.81) with detection rates of 72 and 55% for early and late PE, respectively, for a 10% false positive rate.Conclusion: Detection rates for PE in our Chinese population were lower than the expected 90-95% even after adjusting MoM for local women's characteristics.Funding: General Research Fund (Project number 470513).Tweetable Abstract: Pre-eclampsia screening in the Chinese population had detection rates lower than previously published results. [ABSTRACT FROM AUTHOR]

Seasonal and diurnal variations of carbonyl compounds were investigated in roadside (MK), urban (TW), and suburban (UST) environments in Hong Kong. Thirteen carbonyls (C1–C6) were identified and quantified in the samples. The average total quantified carbonyl concentrations decreased in the order of roadside (12.16 ± 3.52 μg m−3), urban (10.45 ± 4.82 μg m−3), and suburban (5.14 ± 3.35 μg m−3). Formaldehyde was the most abundant species, accounting for ∼52%, ∼52%, and ∼46% of total measured carbonyls at MK, TW, and UST, respectively. At MK, the summer/winter ratios of most carbonyls were below one. The diurnal variations were associated with traffic flows, with high concentrations in daytime but low in nighttime. Good correlations were found between most carbonyls and carbon monoxide (CO), showing primary vehicular emission was the major source at the roadside location. In contrast, the summer/winter ratios of most carbonyls were larger than one at the urban site of TW and their carbonyls correlated well with secondary pollutant of ozone (O3), indicating photochemical reactions contributed significantly in the formation of carbonyls, especially in summer. Distinct diurnal variations of carbonyls were observed at TW on a hazy winter day of 28 Jan 2012. Most carbonyl concentrations reached the first peak at noontime and had the second peak in the evening. The first peak was ascribed to be the products of photochemical reactions as maximum concentrations of nitrogen monoxide (NO) and O3 occurred just before and after the carbonyl peak, respectively. The correlations among the carbonyl species were strong in summer but fair in winter at UST. Natural sources (e.g. biogenic) were usually the major source at the suburban, as far as its surrounding environment is concerned. [ABSTRACT FROM AUTHOR]

Abstract: The mass concentrations of PM1 (particles less than 1.0μm in aerodynamic diameter), organic carbon (OC), elemental carbon (EC), water-soluble ions, and up to 25 elements were reported for 24h aerosol samples collected every sixth day at a roadside sampling station in Hong Kong from October 2004 to September 2005. Annual average PM1 mass concentration was 44.5±19.5μgm−3. EC, OM (organic matter, OC×1.2), and SO4 = were the dominant components, accounting for ∼36%, ∼26%, and ∼24% of PM1, respectively. Other components, i.e., NO3 −, NH4 +, geological material, trace elements and unidentified material, comprised the remaining ∼14%. Annual average OC/EC ratio (0.6±0.3) was low, indicating that primary vehicle exhaust was the major source of carbonaceous aerosols. The seasonal variations of pollutants were due to gas-particle partitioning processes or a change in air mass rather than secondary aerosol produced locally. Vehicle exhaust, secondary aerosols, and waste incinerator/biomass burning were dominant air pollution sources, accounting for ∼38%, ∼22% and ∼16% of PM1, respectively. Pollution episodes during summer (May–August) which were frequently accompanied by tropical storms or typhoons were dominated by vehicle emissions. During winter (November–February) pollution episodes coincided with northeasterly monsoons were characterized by secondary aerosols and incinerator/biomass burning emissions. [Copyright &y& Elsevier]

Abstract: PM2.5 (particle with an aerodynamic diameter less than 2.5µm) was measured in different microenvironments of Hong Kong (including one urban tunnel, one Hong Kong/Mainland boundary roadside site, two urban roadside sites, and one urban ambient site) in 2003. The concentrations of organic carbon (OC), elemental carbon (EC), water-soluble ions, and up to 40 elements (Na to U) were determined. The average PM2.5 mass concentrations were 229±90, 129±95, 69±12, 49±18µgm−3 in the urban tunnel, cross boundary roadside, urban roadside, and urban ambient environments, respectively. Carbonaceous particles (sum of organic material [OM] and EC) were the dominant constituents, on average, accounting for ∼82% of PM2.5 emissions in the tunnel, ∼70% at the three roadside sites, and ∼48% at the ambient site, respectively. The OC/EC ratios were 0.6±0.2 and 0.8±0.1 at the tunnel and roadside sites, respectively, suggesting carbonaceous aerosols were mainly from vehicle exhausts. Higher OC/EC ratio (1.9±0.7) occurred at the ambient site, indicating contributions from secondary organic aerosols. The PM2.5 emission factor for on-road diesel-fueled vehicles in the urban area of Hong Kong was 257±31mg veh−1 km−1, with a composition of ∼51% EC, ∼26% OC, and ∼9% SO4 =. The other inorganic ions and elements made up ∼11% of the total PM2.5 emissions. OC composed the largest fraction (∼51%) in gasoline and liquid petroleum gas (LPG) emissions, followed by EC (∼19%). Diesel engines showed higher emission rates than did gasoline and LPG engines for most pollutants, except for V, Br, Sb, and Ba. [Copyright &y& Elsevier]

Vehicle emissions of volatile organic compounds (VOCs) were determined at the Shing Mun Tunnel, Hong Kong in summer and winter of 2003. One hundred and ten VOCs were quantified in this study. The average concentration of the total measured VOCs at the inlet and outlet of the tunnel were 81 250 pptv and 117 850 pptv, respectively. Among the 110 compounds, ethene, ethyne and toluene were the most abundant species in the tunnel. The total measured VOC emission factors ranged from 67 mg veh-1 km-1 to 148 mg veh-1 km-1, with an average of 115 mg veh-1 km-1. The five most abundant VOCs observed in the tunnel were, in decreasing order, ethene, toluene, n-butane, propane and i-pentane. These five most abundant species contributed over 38% of the total measured VOCs emitted. The high propane and n-butane emissions were found to be associated with liquefied petroleum gas (LPG)-fueled taxis. Fair correlations were observed between marker species (ethene, i-pentane, n-nonane, and benzene, toluene, ethylbenzene and xylenes - BTEX) with fractions of gasoline-fueled or diesel-fueled vehicles. Moreover, ethene, ethyne, and propene are the key species that were abundant in the tunnel but not in gasoline vapors or LPG. The ozone formation potential from the VOCs in Hong Kong was evaluated by the maximum increment reactivity (MIR). It was found to be 568 mg of ozone per vehicle per kilometer traveled. Among them, ethene, propene and toluene contribute most to the ozone-formation reactivity. [ABSTRACT FROM AUTHOR]

The current method of steel bar soil nail construction is both labor intensive as well as expensive and many engineers are considering the use of new soil nail materials. In the present pilot test, an innovative soil nail is constructed by light weight high strength glass fiber-reinforced plastic (GFRP) pipe with the Tube a’ Manchette grouting technique. It is found that this new soil nail system can be handled easily on sites with difficult access. Extensive laboratory as well as field tests were carried out on the GFRP pipe nails and the grouted soil mass and numerical modeling of a field test was performed. The installation of the GFRP pipe, laboratory, and field test results that were carried out in Hong Kong and Korea are discussed in this paper. [ABSTRACT FROM AUTHOR]

The article discusses the Chinese Barriers to Exercise (CBE) scale for adults. It is said that psychometric-analytic properties of the CBE scale is validated in Hong Kong, China. The factors such as family, symptoms, facilities were explored. Results show that the barriers is important in exercise behavior among the adults.

Some unreasonable results from the use of a popular thick plate element are discovered from the analysis of a raft foundation and a pile cap in Hong Kong. To overcome the problems, the authors have developed a new shear deformable beam which can be extended to a general quadrilateral shear deformable plate. The behaviour of this new element under several interesting cases is investigated, and it is demonstrated that the new element possesses very high accuracy under different depth/span ratios, and the results from this new element are good even for a coarse mesh. [ABSTRACT FROM AUTHOR]

Objectives: To study the attitudes of both medical and non-medical students towards the do-not-resuscitate (DNR) decision in a university in Hong Kong, and the factors affecting their attitudes. Methods: A questionnaire-based survey conducted in the campus of a university in Hong Kong. Preferences and priorities of participants on cardiopulmonary resuscitation in various situations and case scenarios, experience of death and dying, prior knowledge of DNR and basic demographic data were evaluated. Results: A total of 766 students participated in the study. There were statistically significant differences in their experience of death and dying, prior knowledge of DNR and basic demographic data were evaluated. Results: A total of 766 students participated in the study. There were statistically significant differences in their students, and between students who had previously experienced death and dying and those who had not. A prior knowledge of DNR significantly affected DNR decision, although 66.4% of non-medical students and 18.7% of medical students had never heard of DNR. 74% of participants from both medical and non-medical fields considered the patient's own wish as the most important factor that the healthcare team should consider when making DNR decisions. Family wishes might not be decisive on the choice of DNR. Conclusions: Students in medical and non-medical fields held different views on DNR. A majority of participants considered the patient's own wish as most important in DNR decisions. Family wishes were considered less important than the patient's own wishes. [ABSTRACT FROM AUTHOR]

A soil reinforcement system using the combination of glass-fiber-reinforced polymer (GFRP) pipe and pressure grouting has been developed by a Korean company. The system is being adopted as slope stabilization measures in Hong Kong. Individual GFRP pipes were designed and installed as soil nails with the exception that two-stage pressure grouting was applied instead of gravity grouting. A full-scale field evaluation on constructability and in situ performance of the system was performed in Hong Kong. The performance of the constructed nails was evaluated by pullout tests. The construction procedure, site adaptations of the Korean product made in Hong Kong, field test procedure, and performance of the constructed soil nails are reported in this paper. [ABSTRACT FROM AUTHOR]

Abstract: Real-world emission factors of PM2.5 (particle''s aerodynamic diameter of less than 2.5μm), NO x (the sum of NO2 and NO), and CO from mixed vehicles in the Shing Mun Tunnel in Hong Kong have been determined. A total of 16 runs were made during varying times that encompassed different traffic fractions of diesel-fueled vehicles. During the study, a total of 27,310 vehicles traversed the tunnel, comprising approximately 50% diesel-fueled vehicles, 41% gasoline-fueled vehicles, and 9% LPG-vehicles. The PM2.5 emission factors, derived from the DRI (Desert Research Institute, USA) particulate sampler, ranged from 0.066 to 0.190g veh−1 km−1. Result from a t-test showed no statistical significance for PM2.5 difference in summer and winter. The PM2.5 emission factors were found to correlate well with NO x (R 2=0.65) and both had a positive relationship with the proportion of diesel-fueled vehicles. Two DustTrak air monitors were also used to monitor PM2.5 masses in the tunnel. The mean emission factor derived from DustTrak, 0.150±0.045g veh−1 km−1, had reasonable agreement with the filter method, 0.131±0.037g veh−1 km−1, demonstrating that the DustTrak air monitor can be used in tunnel studies, but needs careful calibrations with the filter method. The emission factors for PM2.5 mass and NO x were obtained for on-road diesel-fueled vehicles based on the linear regression analysis and they were 0.257±0.031 and 1.931±0.309g veh−1 km−1, respectively. [Copyright &y& Elsevier]

Daily mass concentrations of PM 1.0 (particles less than 1.0 µm in diameter), PM 2.5 (particles less than 2.5 µm in diameter), organic carbon (OC), and elemental carbon (EC) were measured from January through May 2004 at a heavily trafficked sampling site in Hong Kong (PU). The average concentrations for PM 1.0 and PM 2.5 were 35.9 ± 12.4 µ g cm - 3 and 52.3 ± 18.3 µ g cm - 3 . Carbonaceous aerosols were the dominant species in fine particles, accounting for ~ 45.7% of PM 1.0 and ~ 44.4% of PM 2.5 . During the study period, seven fine-particle episodes occurred, due to the influence of long-range transport of air masses from mainland China. PM 1.0 and PM 2.5 responded in similar ways; i.e., with elevated mass and OC concentrations in those episode days. During the sampling period, PM 1.0 OC and EC generally behaved similarly to the carbonaceous aerosols in PM 2.5 , regardless of seasonal variations and influence by regional pollutions. The low and relatively constant OC/EC ratios in PM 1.0 and PM 2.5 indicated that vehicular emissions were major sources of carbonaceous aerosols. PM 1.0 and PM 2.5 had the same dominant sources of vehicular emissions in winter, while in spring PM 2.5 was more influenced by PM 1 - 2.5 (particles 1–2.5 µ m in diameter) that did not form from vehicle exhausts. Therefore, PM 1.0 was a better indicator for vehicular emissions at the Roadside Station. [ABSTRACT FROM AUTHOR]

Six residences were selected (two roadside, two urban, and two rural) to evaluate the indoor–outdoor characteristics of PM2.5 (aerodynamic diameter<2.5 μm) carbonaceous species in Hong Kong during March and April 2004. Twenty-minute-averaged indoor and outdoor PM2.5 concentrations were recorded by DustTrak samplers simultaneously at each site for 3 days to examine diurnal variability of PM2.5 mass concentrations and their indoor-to-outdoor (I/O) ratios. Daily (24-h average) indoor/outdoor PM2.5 samples were collected on pre-fired quartz–fiber filters with battery-powered portable mini-volume samplers and analyzed for organic and elemental carbon (OC, EC) by thermal/optical reflectance (TOR) following the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol. The average indoor and outdoor concentrations of 24 h PM2.5 were 56.7 and 43.8 μg/m3, respectively. The short-term PM2.5 profiles indicated that the penetration of outdoor particles was an important contributor to indoor PM2.5, and a household survey indicated that daily activities were also sources of episodic peaks in indoor PM2.5. The average indoor OC and EC concentrations of 17.1 and 2.8 μg/m3, respectively, accounted for an average of 29.5 and 5.2%, respectively, of indoor PM2.5 mass. The average indoor OC/EC ratios were 5.8, 9.1, and 5.0 in roadside, urban, and rural areas, respectively; while average outdoor OC/EC ratios were 4.0, 4.3, and 4.0, respectively. The average I/O ratios of 24 h PM2.5, OC, and EC were 1.4, 1.8, and 1.2, respectively. High indoor–outdoor correlations (r2) were found for PM2.5 EC (0.96) and mass (0.81), and low correlations were found for OC (0.55), indicative of different organic carbon sources indoors. A simple model implied that about two-thirds of carbonaceous particles in indoor air are originated from outdoor sources. Indoor particulate pollution has received more attentions in Asia. This study presents a case study regarding the fine particulate matter and its carbonaceous compositions at six residential homes in Hong Kong. The characteristics and relationship of atmospheric organic and elemental carbon were discussed indoors and outdoors. The distribution of eight carbon fractions was first reported in indoor samples to interpret potential sources of indoor carbonaceous particles. The data set can provide significant scientific basis for indoor air quality and epidemiology study in Hong Kong and China. [ABSTRACT FROM AUTHOR]

To examine teachers' views of the first batch of graduates of a revised medical curriculum in Asia. A cross-sectional study using a structured questionnaire was carried out to obtain the views of all the clinical teachers involved in teaching final year students of the old curriculum in 2000–01 and the new curriculum in 2001–02 at the University of Hong Kong, which commenced curricular reform in 1997. Nearly 62% of respondents felt that better graduates were being produced with the new curriculum. The majority of them rated the new curriculum students better in nearly all the major goals of the new curriculum, such as self-directed learning initiative, problem solving skills, interpersonal skills and clinical performance in patient care. However, the core knowledge of the new curriculum students was of concern to some teachers. This study focused on the first complete cycle of a revised medical curriculum in Asia. Teachers' views of the new curriculum students were highly positive and they felt that better graduates were being produced. [ABSTRACT FROM AUTHOR]

In order to evaluate the efficacy of convalescent plasma therapy in the treatment of patients with severe acute respiratory syndrome (SARS), 80 SARS patients were given convalescent plasma at Prince of Wales Hospital, Hong Kong, between 20 March and 26 May 2003. Good outcome was defined as discharge by day 22 following the onset of SARS symptoms. Poor outcome was defined as death or hospitalization beyond 22 days. A higher day-22 discharge rate was observed among patients who were given convalescent plasma before day 14 of illness (58.3% vs 15.6%;P<0.001) and among those who were PCR positive and seronegative for coronavirus at the time of plasma infusion (66.7% vs 20%;P=0.001). [ABSTRACT FROM AUTHOR]

Abstract: Fine particulates from ship exhaust are proved to be harmful to human health. To better understand the impact of ship emissions on the particulate matter (PM) level of port-side residential areas, fine particulates (PM2.5) were collected near Kwai Chung and Tsing Yi Container Terminals (KTCT) in Hong Kong during August 2009 to March 2010. The average PM2.5 concentration was 30.5μg/m3. The contribution of ship emissions on fine particulates near the container port was demonstrated by source apportionment. By positive matrix factorization (PMF) analysis, eight potential sources, i.e., residual oil (RO) combustion, marine diesel oil (MDO) combustion, vehicle emission, coal combustion, incineration, crustal and sea-salt, secondary sulfate and secondary nitrate were identified. Among the identified sources, RO combustion and MDO combustion were regarded as ship emissions and accounted for 12% and 7% of PM2.5 respectively. An estimate of 1.8μg/m3 (6%) of secondary sulfate corresponded to 3.6μg/m3 of primary fine particulates from RO combustion. Together with primary PM emitted from ships, the total ambient PM2.5 mass associated with ship emissions at the sampling site was 7.6μg/m3 (25%). [Copyright &y& Elsevier]

Abstract: Real-world vehicle emissions of carbonyls were determined in summer and winter of 2003 at the Shing Mun Tunnel, Hong Kong. Fifteen carbonyl species have been analyzed in this study. The total measured carbonyls emission factors ranged from 21.7 to 68.9mgveh−1 km−1 among different measurement periods, with an average of 35.8±11.9mgveh−1 km−1. Higher carbonyl emissions were found to be associated with a high proportion of diesel-fueled vehicles. Total measured carbonyl emissions from Diesel-fueled Vehicle (DV, 71.5mgveh−1 km−1) were about 7 times higher than those from Non-Diesel-fueled Vehicle (NDV, 10mgveh−1 km−1). The five carbonyls with the largest DV emission factor were, in decreasing order, formaldehyde (38.3mgveh−1 km−1), acetaldehyde (11.4mgveh−1 km−1), acetone (5.3mgveh−1 km−1), crotonaldehyde (5.2mgveh−1 km−1) and benzaldehyde (2.0mg veh−1 km−1). These five carbonyl compounds together accounted for 87% of the sum of all DV carbonyl emission factors. For NDV, the five most abundant carbonyls in NDV emission at the tunnel were, in decreasing order, formaldehyde (3.5mgveh−1 km−1), acetone (1.8mgveh−1 km−1), methyl ethyl ketone (1.6mgveh−1 km−1), m,p-tolualdehyde (1.0mgveh−1 km−1) and acetaldehyde (mgveh−1 km−1). They accounted for 85% of the sum of all NDV carbonyl emission factors. [Copyright &y& Elsevier]

Abstract: As one of the busiest port in the world, ship emissions have become of great concern in Hong Kong. In this study, a detailed maritime emission inventory for ocean-going vessels (OGVs) in Hong Kong with the base year of 2007 was developed. The high-resolution vessel speed profiles determined using the Automatic Identification System (AIS) during 2009 were adopted for the speed data in the estimation. It was obtained that the total ship emissions from 37,150 voyages of OGVs in 2007 were 17,097, 8190, and 1035tonnes accounting for 17%, 11%, and 16% of the total emissions of NOx, SO2, and PM10, respectively. The contribution of ship emissions during transiting was 60–68% for three pollutants while the emissions during hotelling were responsible for the remaining portions. From the emission spatial allocation, the shipping route along the East Lamma Channel and the berthing location of the Kwai Chung and Tsing Yi Container Port comprised the regions with the highest emissions. The OGV emissions in Hong Kong contributed 0.07% NOx, 0.05% SO2, and 0.06% PM10 out of the global total shipping emissions in 2007. [Copyright &y& Elsevier]

Abstract: Real-world vehicle emission factors for seventeen gas and particulate polycyclic aromatic hydrocarbons (PAHs) were quantified in the Shing Mun Tunnel, Hong Kong during summer and winter 2003. Naphthalene, acenaphthylene, and acenaphthene were the most abundant gas PAHs while fluoranthene and pyrene were the most abundant in the particle phase. Most (98%) of the gas PAHs consisted of two- and three-aromatic rings whereas most of the particle-phase PAHs were in four- (∼60%) and five-ring (∼17%) for fresh exhaust emissions. Average emission factors for the gas- and particle PAHs were 950–2564 μg veh−1 km−1 and 22–354 μg veh−1 km−1, respectively. Good correlations were found between diesel markers (fluoranthene and pyrene; 0.85) and gasoline markers (benzo[ghi]perylene and indeno[1,2,3-cd]pyrene; 0.96). Higher PAH emission factors were associated with a higher fraction of diesel-fueled vehicles (DV) passing through the tunnel. Separate emission factors were determined from diesel and non-diesel exhaust by the regression intercept method. The average PAH emission factor (i.e., sum of gas and particle phases) from DV (3085 ± 1058 μg veh−1 km−1) was ∼5 times higher than that from non-diesel-fueled vehicles (NDV, 566 ± 428 μg veh−1 km−1). Ratios of DV to NDV emission factors were high for diesel markers (>24); and low for gasoline markers (<0.4). [Copyright &y& Elsevier]