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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]

The mass, chemical composition and toxicological properties of fine particulates (PM 2.5) emitted from cooking activities in three Hong Kong based restaurants and two simulated cooking experiments were characterized. Extracts from the PM 2.5 samples elicited significant biological activities [cell viability, generation of reactive oxygen species (ROS), DNA damage and inflammation effect (TNF-α)] in a dose-dependent manner. The composition of PAHs, oxygenated PAHs (OPAHs) and azaarenes (AZAs) mixtures differed between samples. The concentration ranges of the Σ30PAHs, Σ17OPAHs and Σ4AZAs and Σ7Carbonyls in the samples were 9627–23,452 pg m−3, 503–3700 pg m−3, 33–263 pg m−3 and 158 – 5328 ng m−3, respectively. Cell viability caused by extracts from the samples was positively correlated to the concentration of benzo[a]anthracene, indeno[1,2,3-cd]pyrene and 1,4-naphthoquinone in the PM 2.5 extracts. Cellular ROS production (upon exposure to extracts) was positively correlated with the concentrations of PM 2.5 , decaldehyde, acridine, Σ17OPAHs and 7 individual OPAHs. TNF-α showed significant positive correlations with the concentrations of most chemical species (elemental carbon, 16 individual PAHs including benzo[a]pyrene, Σ30PAHs, SO 4 2−, Ca2+, Ca, Na, K, Ti, Cr, Mn, Fe, Cu and Zn). The concentrations of Al, Ti, Mn, Σ30PAHs and 8 individual PAHs including benzo[a]pyrene in the samples were positively correlated with DNA damage caused by extracts from the samples. This study demonstrates that inhalation of PM 2.5 emitted from cooking could result in adverse human health effects. [Display omitted] • Cooking PM 2.5 emissions elicited significant bioreactivity in dose-dependent manner. • Cantonese cooking style emitted highest PM 2.5 and chemical species concentrations. • Positive significant correlations showed between PM 2.5 /OPAHs and ROS. • Majority of high molecular weight PAHs showed strong correlations with TNF-α. • Benzo[a]pyrene demonstrated significant positive correlation against DNA damage. [ABSTRACT FROM AUTHOR]

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: The chemical characteristics of ambient particulate matters in urban and rural areas of Hong Kong were determined in this study. A monitoring program starting from November 2000 to February 2001 (winter) and June 2001 to August 2001 (summer) for PM10 and PM2.5 was performed at three monitoring stations in Hong Kong. Twenty-four-hour PM10 and PM2.5 samples were collected once every 6 days at two urban sites, PolyU and KT, and every 12 days at a background site, HT, with Hi-Vol samplers. High concentrations of OC, EC (except in PolyU), water-soluble ions and elements were observed in winter among the three sampling sites for PM10 and PM2.5 fractions. Seasonal variations were significant in background HT. Dilution effect due to the increase in mixing depth and precipitation in summer reduced the concentrations of particulate matters. Long-range transport could contribute to the higher concentrations of particulate matter in the winter. Chemical mass closure calculations were performed for PM10 and PM2.5 observed. Mass closure improved when separate factors (1.4 and 1.9 respectively) were used to convert water-soluble organic carbon (WSOC) and water-insoluble organic carbon (WINSOC) into corresponding organic masses. The urban sites showed high percentages of water-soluble ions in winter and high percentages of carbonaceous species in summer. Better results were obtained for the chemical mass closure analysis in winter than in summer. High temperature and solar radiation in summer increased the rate of the complex photochemical reaction in the atmosphere. Therefore the chemical mass closure analysis would underestimate the volatized species and secondary aerosols during summer. [Copyright &y& Elsevier]

Five buildings located near roadsides (an office and a classroom with mechanical ventilation (MV) and three residences with natural ventilation (NV)) were selected with a view to characterising indoor and outdoor concentrations of organic (OC) and elemental carbon (EC). PM2.5 samples were analysed using a thermal optical reflectance (TOR) method for OC and EC concentrations. The average 24-h PM2.5 outdoor concentration was 78.4μgm-3, whilst the average outdoor OC and EC concentrations were 12.6 and 6.4μgm-3, respectively, accounting for 17% and 9%, respectively of the outdoor PM2.5 mass. The average 24-h PM2.5 indoor concentration was 55.4μgm-3 of which indoor OC and EC were 11.3 and 4.8μgm-3, respectively, accounted for 22% and 9%, respectively. The mean value of indoor to outdoor ratios (I/O ratios) of PM2.5 was 0.80, with a close correlation between indoor and outdoor PM2.5 concentrations, especially in the NV residences. The average I/O ratios of OC and EC were 1.02 and 0.80, respectively. The higher ratio for OC reflects indoor sources of OC, which do not appear to occur for EC. The major source of indoor EC, OC and PM2.5, however, appears to be penetration of outdoor air, with a much greater attenuation in the MV buildings studied. [Copyright &y& Elsevier]

PM10 and PM2.5 chemical source profiles from Hong Kong were investigated for paved road dust and soil. These profiles are needed for urban-scale speciated emissions inventories and for source apportionment by receptor modeling. Five urban soil and five paved road dust samples were collected, dried and sieved, resuspended in a laboratory chamber, air drawn through PM10 and PM2.5 inlet onto Teflon and quartz filters. The filter samples were submitted for both gravimetric and chemical analyses. Chemical analyses included X-ray fluorescence for elemental composition, ion chromatography for water soluble chloride, nitrate, sulfate, atomic absorption spectrophotometry for water soluble sodium and potassium, automated colorimetric analysis for ammonium and thermal/optical reflectance analysis for carbon species. The PM2.5 constituted 11–30% of the PM10 in all geological samples. Al, Si and organic carbon (OC) are abundant constituents in all paved road dust and soil samples. The chemical abundances of PM2.5 and PM10 for a given source type were similar for most species. In addition, results from resuspended soil (three sets), paved road dust (five sets), aggregate (three sets) and cement (two sets) were obtained from Hong Kong Environmental Protection Department (HKEPD) for comparison as well as mass closure analysis. [Copyright &y& Elsevier]

Aerosol samples for PM10 and PM2.5 were collected in wintertime from November 2000 to February 2001 at three different sampling locations in Hong Kong. PM10 and PM2.5 were collected by high-volume (hi-vol.) samplers and the concentrations of major elements, ions, organic and elemental carbons were quantified. The ratios of PM2.5/PM10 were 0.61 and 0.78 at the PolyU campus and Kwun Tong (KT), respectively. These results indicated that the concentrations of PM2.5 contribute the majority of the PM10 fraction. The concentrations of anthropogenic species (e.g. Pb and Cu) in PM10 and PM2.5measured at urban areas were generally higher than at an urban background site (Hok Tsui, HT). The major fractions of sulfate at three monitoring sites are non-sea-salts (nss) sulfates. Although HT is located in coastal areas, the contribution of sea salts to sulfate in fine particles was small, indicating a substantial anthropogenic origin. The OC/EC ratios were less than 2 in PolyU and KT monitoring stations for PM10 and PM2.5. However, the OC/EC ratios were over 3 at HT for both PM10 and PM2.5. This indicates the presence of secondary organic aerosols. Correlations between OC and EC as well as OC and sulfate in HT during both seasons were used to prove that atmospheric transport and transformation of anthropogenic organic species from northeastern area was the dominant source in winter. The chemical composition of the samples was reconstructed from the observed elemental composition. The contribution of the seven components, namely crustal matter, sea salt, ammonium, sulfate, nitrate, elemental carbon and organic matter accounted for 77–84% of the PM10 and PM2.5 mass in the urban area (PolyU and KT) and 74% for Hok Tsui (HT). Sulfate, organic matter and elemental carbon are the major constituents in particles especially in PM2.5 collected at PolyU and KT. The major constituents of PM10 in HT are sea salt and sulfate. [Copyright &y& Elsevier]

To determine the characteristic of carbonaceous species in atmospheric particles in Hong Kong, PM10 and PM2.5 samples were collected using high volume (hi-vol.) air samplers from November 2000 to February 2001. The organic carbon (OC) and elemental carbon (EC) were analyzed by the selective thermal manganese dioxide oxidation (TMO) method. The ratios of PM2.5/PM10 mass ratios were 0.61, 0.78 and 0.53 for particulate matter collected at PolyU station (PolyU, near a major traffic corridor), Kwun Tong station (KT, mixed residential/commercial/industrial) and the Hok Tsui background station (HT), respectively. These results indicate that the PM2.5 concentrations constitute the majority of the PM10 concentrations, especially in urban and industrial areas of Hong Kong. The average concentrations at the three sites ranged from 73.11 to 83.52 μg/m3 for PM10 and from 42.37 to 57.38 μg/m3 for PM2.5. The highest daily mass concentrations of PM10 and PM2.5 were 125.89 μg/m3 and 116.89 μg/m3 at KT, respectively. The correlation between PM10 and PM2.5 was high at KT and HT (r>0.9, P<0.01). This means that the sources of PM10 and PM2.5 may be the same at both sites. The highest mean concentration of OC (12.02 μg/m3) and EC (6.86 μg/m3) in PM10 was found at the PolyU among the three sites. For PM2.5, the highest mean concentration of OC (10.16 μg/m3) was at KT while the highest mean concentration of EC (7.95 μg/m3) was at PolyU. However, the background concentrations at HT were higher than another background area, Kosan, Korea. Transportation of pollutants from the Asian continent may be responsible for the elevations of EC+OC at the remote site. More than 74% of the EC and more than 79% of the OC were found in the PM2.5 fraction at the three sampling locations. At PolyU station, PM2.5 consisted of 18.18% OC and 11.16% EC while 17.70% OC and 8.81% EC were found in KT station. Thus OC and EC are major constituents of aerosols in Hong Kong. OC/EC ratios for PM10 and PM2.5 were less than 2 at PolyU and KT stations while the ratio exceeded 3 at HT background station. This indicates that OC measured in the urban area may be emitted directly as a primary aerosol. [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]

Field investigations of target air pollutants at two of the most famous temples in Hong Kong were conducted. The air pollution problems in these two temples during peak and non-peak periods were characterized. The target air pollutants included particulate matters (PM10, PM2. 5), volatile organic compounds (VOCs), carbonyl compounds, carbon monoxide (CO), nitrogen oxides (NO x ), methane (CH4), non-methane hydrocarbons (NMHC), organic carbon (OC), elemental carbon (EC), and inorganic ions (Cl−, NO3 −, SO4 2−, Na+, NH4 +, and K+). The pollutant levels of the two temples during peak period were shown to be significantly higher than those during non-peak period. The highest average CO level was obtained at Temple 1 during peak period, which exceeded IAQO 8-h Good Class criteria. In general, the average PM2. 5/PM10 ratios were approximately 82%. The results revealed that the fine particulates (PM2. 5) constituted the majority of suspended particulates at both temples. It was noted that formaldehyde was the most abundant carbonyl compounds, followed by acetaldehyde. At Temple 1 during peak period, the average benzene concentration exceeded almost 8 times more than Indoor Air Quality Objectives for Office Buildings and Public Places (IAQO) [HKEPD, 2003. Guidance notes for the management of indoor air quality in offices and public places. Indoor air quality management group, The Government of the Hong Kong Special Administrative Region. ] Good Class criteria. The average OC/EC ratios ranged from 2. 6 to 17 in PM10 and from 4. 2 to 18 in PM2. 5 at two temples, which suggested that OC measured in these two temple areas may be due to both direct emission from incense burning and secondary formation by chemical reactions. The total mass of inorganic ions, organic carbon, and elemental carbon accounted for about 71% in PM2. 5 and 72% in PM10. [Copyright &y& Elsevier]

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]

PM2.5 and PM10 samples were collected at two sampling sites in Hong Kong in wintertime from November 2000 to March 2001 and in summertime from June to August 2001. The concentrations of 16 selected polycyclic aromatic hydrocarbons (PAHs) in aerosols were quantified. Spatial and seasonal variations of PAHs were characterized. The dominated PAHs in PM2.5 and PM10 included benzo[b]fluoranthene, pyrene, fluoranthene, indeno[1,2,3-cd]pyrene and chrysene, accounting for 50–82% of total PAHs. The sum of 16 PAHs in PM2.5 at roadside ranged from 3 to 330 ng/m3, and in PM10 between 5 and 297 ng/m3, whereas at a residential/industrial/commercial site, the total PAHs in PM2.5 was from 0.5 to 122 ng/m3, and 2–269 ng/m3 in PM10. Results indicated that most of the PAHs were in the PM2.5 fraction. Spatial variations were predominantly due to the difference of source strength. For both PM2.5 and PM10, the total PAHs at PU site was higher than that at KT site. The average concentrations of individual PAHs in aerosols at PU site were also higher than that at KT site. Higher winter PAHs concentrations and lower summer concentrations were observed at the two sites. Higher winter PAHs concentrations were mainly caused by local emission sources superimposed by highly polluted air masses from Mainland China. The lower summer PAHs concentrations were likely due to easier dispersion of air pollutants, washout effects and to a lesser extent, photo-degradation and higher percentage in the air in vapor phase. Potential sources of PAHs in aerosols were identified using the diagnostic ratios between PAHs and PCA analysis. At PU site, vehicular emissions were the main contributors of particle-associated PAHs, and stationary combustion sources may also contribute to the particulate PAHs. On the contrary, at the KT site, PAHs in aerosols were predominantly from gasoline and diesel engines. [Copyright &y& Elsevier]

Identifies volatile organic compounds (VOCs) in different urban areas in Hong Kong. Concentrations of VOCs; Effect of automobile exhaust and industrial emissions; Major pollutants from vehicle exhausts.

The emissions before and after atmospheric oxidation from three gasoline vehicles were characterized under different driving conditions (idling, cruising and New European Driving Cycle (NEDC)). The total quantified volatile organic compounds (VOCs) emission factors for the vehicles ranged from 18.4 to 2728.7 mg/kg depending on driving conditions. The organic aerosol mass concentrations showed substantial increase (∼7.6–10.8 times) after ageing process, implying that vehicular emissions were an important source of secondary organic aerosols (SOAs). The total quantified organic aerosol mass concentrations in aged samples ranged from 77.7 to 480.5 ng m−3 under different test conditions. Aromatic and alkenoic acids were identified as major organic aerosols after ageing. The emission factors of VOCs were higher under idling condition compared to the other driving modes for all vehicles. High VOCs emissions can potentially lead to high secondary organic aerosol (SOA) formation inside the reactor and more robust SOA formation under idling condition in all analysis. The gasoline direct injection (GDI) vehicle with latest year of manufacture in EURO 4 standard can pose lower primary emissions of organic substances, but nevertheless the composition of emitted VOCs demonstrates higher SOA yield and SOA formation. Further analysis proposes engine type is the key factor on primary VOC composition under idling. The findings suggest a need to revise existing regulation of composition of organic substances. [Display omitted] • Total VOCs emission factors range from 18.4 to 2728.7 mg/kg for test vehicles. • Total VOCs emissions are highest under idling and followed by NEDC and cruising. • Primary particle emissions are in ascending order: idling < cruising < NEDC. • Idling produces highest amount of aged organic aerosols against other driving modes. • Engine types affect fresh VOCs compositions and further overall SOA yields. [ABSTRACT FROM AUTHOR]

The chemical properties of fresh and aged aerosol emitted during controlled vehicular exhaust emissions were characterized in the analysis. Pyrene (10417.1 ± 534.9 ng kg−1) is the most abundant of all analyzed compounds in total fresh emission and succinic acid (57359.8 ± 4000.3 ng kg−1) is for the total aged emission. The fresh emission factors (EF fresh) of all compounds in the n-alkanes group demonstrate higher average emissions for the two vehicles with EURO 3 standard compared to the other vehicles. The EF fresh for benzo [ a ]pyrene is in descending order: G1 (183.1 ± 144.7 ng kg−1) > G3 (103.4 ± 60.1 ng kg−1) > G4 (91.2 ± 80.1 ng kg−1) > G2 (88.6 ± 93.9 ng kg−1). Aged/fresh (A/F) emission ratios (>20) confirmed that these diacid compounds are generated by the photooxidation of primary pollutants that emitted from gasoline combustions. High A/F ratios (>200) in phthalic acid, isophthalic acid and terephthalic acid under idling mode imply relatively more intense photochemical reactions for their productions compared with other chemical groups. Strong positive correlations (r > 0.6) were observed between the degradation of toluene and formations of pinonic acid, succinic acid, adipic acid, terephthalic acid, glutaric acid and citramalic acid after the aging process, suggesting possible photooxidation of toluene that can lead to secondary organic aerosol (SOA) formation in the urban atmosphere. The findings demonstrate that vehicle emission standards for pollution in relation to the change of particulate matter chemical compositions and SOA formations. The results warrant a need for regulated reformulation for such vehicles. [Display omitted] • Pyrene and succinic acid dominate in total fresh and aged emission respectively. • Euro 3 vehicles pose highest fresh emission for all n-alkane compounds. • Phthalic acid is most abundant EF fresh component in aromatic acid group compounds. • High A/F ratios (>200) in diacid compounds show intense photochemical aging process. • Strong correlation between acid species and toluene implies possible photooxidation. [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: 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: 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]

Dicarboxylic acids in atmospheric aerosols have received much attention because of their potential roles in affecting the global climate. The composition and the sources of dicarboxylic acids in PM2.5 were studied at one remote and two urban sites in Hong Kong in the winter of 2000 and in the summer of 2001. Oxalate was the dominant dicarboxylic acid in all samples. The winter oxalate concentrations were high and spatially uniform, with an average value of 0.36 μg m−3, but the summer oxalate concentrations were low and had a large spatial variation. The influence of meteorological factors on the concentrations of dicarboxylic acids was also studied. The ratio of malonate to succinate was used to distinguish primary sources from secondary sources of these acids. This ratio at all three sites was close to that from direct vehicular exhaust in the winter, but it was close to that of secondary reactions in the summer. Hence, the acids were attributed to vehicular emissions in the winter and secondary sources in the summer. This hypothesis is also supported by a good correlation of oxalate with sulfate in the summer but a poor one in the winter. The correlations of oxalate with malonate, succinate, sulfate and K+ were also studied in terms of the routes of secondary formation of these dicarboxylic acids. [Copyright &y& Elsevier]