scholarly journals Evaluation of traffic exhaust contributions to ambient carbonaceous submicron particulate matter in an urban roadside environment in Hong Kong

2017 ◽  
Author(s):  
Berto P. Lee ◽  
Peter K. K. Louie ◽  
Connie Luk ◽  
Chak K. Chan
Keyword(s):  
Hong Kong ◽  
Particulate Matter ◽  
Elemental Carbon ◽  
Road Traffic ◽  
Control Strategies ◽  
Carbonaceous Aerosol ◽  
Local Source ◽  
Dispersion Modeling ◽  
Vehicle Exhaust ◽  
Road Traffic Emissions

Abstract. Road traffic has significant impacts on local air quality particularly in densely urbanized and populated areas where vehicle emissions are a major local source of ambient particulate matter. Characterization studies on road traffic emissions in Hong Kong are sparse due to the complexity of the urban built environment and the encountered transient engine loads which make emission factor and dispersion modeling approaches difficult to implement. This study provides an estimation of the contribution of vehicles powered by different fuels (gasoline, diesel, LPG) to carbonaceous aerosol based on ambient aerosol mass spectrometer (AMS) and elemental carbon (EC) measurements and real traffic data in an urban inner city environment with the aim to gauge the importance of different vehicle types to particulate matter burdens in a typical urban street canyon. On an average per-vehicle basis, contributions of diesel and gasoline vehicles to carbonaceous PM1 were similar, contrary to previous studies which attributed higher particulate matter emissions to diesel vehicles. This clear reduction is likely due to recent control strategies targeted at commercial vehicles and buses. LPG vehicles were found to be a negligible source of elemental carbon and only small contributor to organic particulate mass despite their high abundance in the traffic mix. Gasoline vehicle exhaust contained similar amounts of elemental carbon and organic species, while diesel vehicle exhaust was dominated by elemental carbon.

scholarly journals Evaluation of traffic exhaust contributions to ambient carbonaceous submicron particulate matter in an urban roadside environment in Hong Kong

2017 ◽  
Vol 17 (24) ◽  
pp. 15121-15135 ◽  
Author(s):  
Berto Paul Lee ◽  
Peter Kwok Keung Louie ◽  
Connie Luk ◽  
Chak Keung Chan
Keyword(s):  
Hong Kong ◽  
Particulate Matter ◽  
Road Traffic ◽  
Control Strategies ◽  
Local Source ◽  
Carbonaceous Particle ◽  
Gasoline Engines ◽  
Diesel Vehicles ◽  
Aerosol Mass ◽  
Gasoline Vehicles

Abstract. Road traffic has significant impacts on air quality particularly in densely urbanized and populated areas where vehicle emissions are a major local source of ambient particulate matter. Engine type (i.e., fuel use) significantly impacts the chemical characteristics of tailpipe emission, and thus the distribution of engine types in traffic impacts measured ambient concentrations. This study provides an estimation of the contribution of vehicles powered by different fuels (gasoline, diesel, LPG) to carbonaceous submicron aerosol mass (PM1) based on ambient aerosol mass spectrometer (AMS) and elemental carbon (EC) measurements and vehicle count data in an urban inner city environment in Hong Kong with the aim to gauge the importance of different engine types to particulate matter burdens in a typical urban street canyon. On an average per-vehicle basis, gasoline vehicles emitted 75 and 93 % more organics than diesel and LPG vehicles, respectively, while EC emissions from diesel vehicles were 45 % higher than those from gasoline vehicles. LPG vehicles showed no appreciable contributions to EC and thus overall represented a small contributor to traffic-related primary ambient PM1 despite their high abundance (∼ 30 %) in the traffic mix. Total carbonaceous particle mass contributions to ambient PM1 from diesel engines were only marginally higher (∼ 4 %) than those from gasoline engines, which is likely an effect of recently introduced control strategies targeted at commercial vehicles and buses. Overall, gasoline vehicles contributed 1.2 µg m−3 of EC and 1.1 µ m−3 of organics, LPG vehicles 0.6 µg m−3 of organics and diesel vehicles 2.0 µg m−3 of EC and 0.7 µg m−3 of organics to ambient carbonaceous PM1.

scholarly journals Sources of PM<sub>2.5</sub> carbonaceous aerosol in Riyadh, Saudi Arabia

2017 ◽  
Author(s):  
Qijing Bian ◽  
Badr Alharbi ◽  
Mohammed M. Sharee ◽  
Tahir Husai ◽  
Mohammad J. Pasha ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Air Quality ◽  
Organic Carbon ◽  
Pollution Control ◽  
Elemental Carbon ◽  
Control Strategies ◽  
Continuous Method ◽  
Carbonaceous Aerosol ◽  
Abstract Knowledge ◽  
The City

Abstract. Knowledge of the sources of carbonaceous aerosol affecting air quality in Riyadh, Saudi Arabia is limited, but needed for the development of pollution control strategies. We conducted sampling of PM2.5 from April to September, 2012 at various sites in the city, and used a thermo-optical semi-continuous method to quantify the organic carbon (OC) and elemental carbon (EC) concentrations. The average OC and EC concentrations were 4.7 ± 4.4 and 2.1 ± 2.5 μg  m

scholarly journals Near-Road Traffic-Related Air Pollution: Resuspended PM2.5 from Highways and Arterials

2020 ◽  
Vol 17 (8) ◽  
pp. 2851 ◽  
Author(s):  
Mohammad Hashem Askariyeh ◽  
Madhusudhan Venugopal ◽  
Haneen Khreis ◽  
Andrew Birt ◽  
Josias Zietsman
Keyword(s):  
Air Pollution ◽  
Particulate Matter ◽  
Environmental Protection Agency ◽  
Urban Areas ◽  
Road Traffic ◽  
Fine Particulate Matter ◽  
Dispersion Modeling ◽  
Hotspot Analysis ◽  
Adverse Health Effects ◽  
Transportation Sector

Recent studies suggest that the transportation sector is a major contributor to fine particulate matter (PM2.5) in urban areas. A growing body of literature indicates PM2.5 exposure can lead to adverse health effects, and that PM2.5 concentrations are often elevated close to roadways. The transportation sector produces PM2.5 emissions from combustion, brake wear, tire wear, and resuspended dust. Traffic-related resuspended dust is particulate matter, previously deposited on the surface of roadways that becomes resuspended into the air by the movement of traffic. The objective of this study was to use regulatory guidelines to model the contribution of resuspended dust to near-road traffic-related PM2.5 concentrations. The U.S. Environmental Protection Agency (EPA) guidelines for quantitative hotspot analysis were used to predict traffic-related PM2.5 concentrations for a small network in Dallas, Texas. Results show that the inclusion of resuspended dust in the emission and dispersion modeling chain increases prediction of near-road PM2.5 concentrations by up to 74%. The results also suggest elevated PM2.5 concentrations near arterial roads. Our results are discussed in the context of human exposure to traffic-related air pollution.

scholarly journals Towards On-Line 14C Analysis of Carbonaceous Aerosol Fractions

Radiocarbon ◽  
2010 ◽  
Vol 52 (2) ◽  
pp. 761-768 ◽  
Author(s):  
Nolwenn Perron ◽  
Sönke Szidat ◽  
Simon Fahrni ◽  
Matthias Ruff ◽  
Lukas Wacker ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Source Apportionment ◽  
Elemental Carbon ◽  
Ion Source ◽  
Carbonaceous Aerosol ◽  
Feeding System ◽  
Line System ◽  
Accelerator Mass Spectrometer ◽  
On Line ◽  
Aerosol Source

Atmospheric carbonaceous aerosol is traditionally divided into organic carbon (OC) and elemental carbon (EC). Their respective carbon amounts are usually analyzed by means of an OC/EC analyzer and their fossil and non-fossil origins can be determined by radiocarbon analysis, which has proven to be a powerful tool for carbonaceous aerosol source apportionment. Thus far, separation of OC and EC has been performed off-line by manual and time-consuming techniques. We present an on-line system that couples a commercial OC/EC analyzer with the gas ion source of the accelerator mass spectrometer (AMS) MICADAS and its CO2 feeding system. The performance achieved with reference materials and blanks are discussed to demonstrate the potential of this coupling for source apportionment of atmospheric carbonaceous particulate matter.

scholarly journals Characterization and source apportionment of atmospheric organic and elemental carbon during fall and winter of 2003 in Xi'an, China

2005 ◽  
Vol 5 (3) ◽  
pp. 3561-3593 ◽  
Author(s):  
J. J. Cao ◽  
J. C. Chow ◽  
S. C. Lee ◽  
Y. Li ◽  
S. W. Chen ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Diesel Exhaust ◽  
Coal Combustion ◽  
Elemental Carbon ◽  
Motor Vehicle ◽  
Principal Component ◽  
Total Carbon ◽  
Carbonaceous Aerosol ◽  
Vehicle Exhaust ◽  
Carbon Fraction

Abstract. Continuous observation of atmospheric organic and elemental carbon (OC, EC) were conducted at Xi'an during high pollution seasons from September 2003 to February 2004. PM2.5 samples were collected on pre-fired quartz-fiber filters with battery-powered mini-volume samplers every day and PM10 samples were collected every third days. Three types of source samples (i.e., coal-combustion, motor vehicle exhaust, and biomass burning) were also collected during ambient sampling period. Ambient and source samples were analyzed for OC and EC by thermal/optical reflectance (TOR) following the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol. The average PM2.5 OC concentrations in fall and winter were 34.1±18.0 µg m-3 and 61.9±33.2 µg m-3, respectively, while EC were 11.3±6.9 µg m-3 and 12.3±5.3 µg m-3, respectively. Most of OC and EC were associated with fine particle (PM2.5) mode. The OC and EC levels at Xi'an are higher than most urban cities in Asia. The OC and EC in fall were found to be strongly correlated (R2>0.9), with moderate correlation in winter (R2=0.66). The carbonaceous aerosol accounted for 48.8±10.1% of the PM2.5 during fall and 45.9±7.5% during winter. Average OC/EC ratio was 3.3 in fall and 5.1 in winter with individual OC/EC ratios constantly exceeding 2.0. Elevated OC/EC ratios were found during heating seasons with increased coal combustion. The contribution of secondary organic carbon was not significant during winter. The time series of OC and EC showed periodic variability. Traffic contributes 5 and 7 day peaks in the spectrum, precipitation appears as a 10 day periodicity and biomass burning can be identified as a 24 day periodicity. Total carbon (TC) was apportioned by absolute principal component analysis (APCA) using the 8 carbon fraction data (OC1, OC2, OC3, OC4, EC1, EC2, EC3, and OP [a pyrolyzed carbon fraction]). TC attributes 73% to gasoline exhaust, 23% to diesel exhaust, and 4% to biomass burning during fall. However, TC attributes 44% each to gasoline exhaust and coal burning, 9% to biomass burning, and 3% to diesel exhaust during winter.

scholarly journals Effectiveness of replacing catalytic converters in LPG-fueled vehicles in Hong Kong

2015 ◽  
Vol 15 (24) ◽  
pp. 35939-35990 ◽  
Author(s):  
X. P. Lyu ◽  
H. Guo ◽  
I. J. Simpson ◽  
S. Meinardi ◽  
P. K. K. Louie ◽  
...  
Keyword(s):  
Hong Kong ◽  
Vehicle Emissions ◽  
Intervention Program ◽  
Control Strategies ◽  
Ambient Air ◽  
Receptor Modeling ◽  
Liquefied Petroleum Gas ◽  
Vehicle Exhaust ◽  
Reduction Percentage

Abstract. Many taxis and public buses are powered by liquefied petroleum gas (LPG) in Hong Kong. With more vehicles using LPG, they have become the major contributor to ambient volatile organic compounds (VOCs) in Hong Kong. An intervention program aimed to reduce the emissions of VOCs and nitrogen oxides (NOx) from LPG-fueled vehicles was implemented by the Hong Kong Government in September 2013. Long-term real-time measurements indicated that the program was remarkably effective in reducing LPG-related VOCs, NOx and nitric oxide (NO) in the atmosphere. Receptor modeling results further revealed that propane, propene, i-butane, n-butane and NO in LPG-fueled vehicle exhaust emissions decreased by 37.3 ± 0.4, 50.2 ± 0.3, 32.9 ± 0.4, 41.1 ± 0.4 and 75.9 ± 0.3 %, respectively, during the implementation of the program. In contrast, despite the reduction of VOCs and NOx, the O3 production following the program increased by 0.25 ± 0.04 ppbv h−1 (4.8 %). Moreover, the production rate of HOx decreased due to the reduction of VOCs, whereas NO reduction resulted in a more significant decrease of the HOx in destruction compared to the decrease in production, and an increase of hydroxyl (OH) and hydroperoxyl (HO2). Analysis of O3-VOCs-NOx sensitivity in ambient air indicated VOC-limited regimes in the O3 formation before and during the program. Moreover, a maximum reduction percentage of NOx (i.e., 29.4 %) and the lowest reduction ratio of VOCs / NOx (i.e., ~ 3 : 1) in LPG-fueled vehicle emissions were determined to give a zero O3 increment. The findings are of great help to future formulation and implementation of control strategies on vehicle emissions in Hong Kong.

scholarly journals Variability of organic and elemental carbon, water soluble organic carbon, and isotopes in Hong Kong

2006 ◽  
Vol 6 (12) ◽  
pp. 4569-4576 ◽  
Author(s):  
K. F. Ho ◽  
S. C. Lee ◽  
J. J. Cao ◽  
Y. S. Li ◽  
J. C. Chow ◽  
...  
Keyword(s):  
Hong Kong ◽  
Organic Carbon ◽  
Elemental Carbon ◽  
Motor Vehicle ◽  
Regional Scale ◽  
Water Soluble ◽  
Total Carbon ◽  
Carbonaceous Aerosol ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. To determine the levels and variations of carbonaceous aerosol in Hong Kong, PM2.5 and PM10 samples were collected by high volume (Hi-vol) samplers at three monitoring stations (representing middle-scale roadside, urban-, and regional-scale environments) during winter (November 2000 to February 2001) and summer (June 2001 to August 2001) periods. The highest concentrations of organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC) were found at the middle-scale roadside site with the lowest at the regional-scale site. The percentages of WSOC in total carbon at these sites were inversely correlated with their concentrations (i.e., the highest percentages of WSOC were observed at the regional-scale site). A high WSOC fraction may be associated with aged aerosol because of the secondary formation by photochemical oxidation of organic precursors of anthropogenic pollutants during transport. The annual average of isotope abundances (δ13C) of OC and EC were –26.9±0.5‰ and –25.6±0.1‰, respectively. There were no notable differences for seasonal distributions of carbon isotopic composition, consistent with motor vehicle emissions being the main source contributors of carbonaceous aerosol in Hong Kong. OC 13C abundances at the regional-scale site were higher than those at the middle-scale roadside and urban sites, consistent with secondary organic aerosols of biogenic origin.

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