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

2016 ◽  
Vol 16 (10) ◽  
pp. 6609-6626 ◽  
Author(s):  
Xiaopu Lyu ◽  
Hai Guo ◽  
Isobel J. Simpson ◽  
Simone Meinardi ◽  
Peter K. K. Louie ◽  
...  
Keyword(s):  
Hong Kong ◽  
Intervention Program ◽  
Control Strategies ◽  
Ambient Air ◽  
Receptor Modeling ◽  
Positive Contribution ◽  
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 which 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 40.8 ± 0.1, 45.7 ± 0.2, 35.7 ± 0.1, 47.8 ± 0.1 and 88.6 ± 0.7 %, respectively, during the implementation of the program. In contrast, despite the reduction of VOCs and NOx, O3 following the program increased by 0.40 ± 0.03 ppbv (∼  5.6 %). The LPG-fueled vehicle exhaust was generally destructive to OH and HO2. However, the destruction effect weakened for OH and it even turned to positive contribution to HO2 during the program. These changes led to the increases of OH, HO2 and HO2 ∕ OH ratio, which might explain the positive O3 increment. 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., 69 %) and the lowest reduction ratio of VOCs ∕ NOx (i.e., 1.1) in LPG-fueled vehicle exhaust 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, and could be extended to other regions in China and around the world.

scholarly journals Receptor Model Source Apportionment of Nonmethane Hydrocarbons in Mexico City

2002 ◽  
Vol 2 ◽  
pp. 844-860 ◽  
Author(s):  
V. Mugica ◽  
J. Watson ◽  
E. Vega ◽  
E. Reyes ◽  
M.E. Ruiz ◽  
...  
Keyword(s):  
Mexico City ◽  
Motor Vehicle ◽  
Ambient Air ◽  
Nonmethane Hydrocarbons ◽  
Receptor Model ◽  
Liquefied Petroleum Gas ◽  
Vehicle Exhaust ◽  
Source Profiles ◽  
Source Contributions ◽  
Initial Source

With the purpose of estimating the source contributions of nonmethane hydrocarbons (NMHC) to the atmosphere at three different sites in the Mexico City Metropolitan Area, 92 ambient air samples were measured from February 23 to March 22 of 1997. Light- and heavy-duty vehicular profiles were determined to differentiate the NMHC contribution of diesel and gasoline to the atmosphere. Food cooking source profiles were also determined for chemical mass balance receptor model application. Initial source contribution estimates were carried out to determine the adequate combination of source profiles and fitting species. Ambient samples of NMHC were apportioned to motor vehicle exhaust, gasoline vapor, handling and distribution of liquefied petroleum gas (LP gas), asphalt operations, painting operations, landfills, and food cooking. Both gasoline and diesel motor vehicle exhaust were the major NMHC contributors for all sites and times, with a percentage of up to 75%. The average motor vehicle exhaust contributions increased during the day. In contrast, LP gas contribution was higher during the morning than in the afternoon. Apportionment for the most abundant individual NMHC showed that the vehicular source is the major contributor to acetylene, ethylene, pentanes, n-hexane, toluene, and xylenes, while handling and distribution of LP gas was the major source contributor to propane and butanes. Comparison between CMB estimates of NMHC and the emission inventory showed a good agreement for vehicles, handling and distribution of LP gas, and painting operations; nevertheless, emissions from diesel exhaust and asphalt operations showed differences, and the results suggest that these emissions could be underestimated.

scholarly journals Chemical characterization and source identification of PM<sub>2.5</sub> at multiple sites in the Beijing–Tianjin–Hebei region, China

2017 ◽  
Vol 17 (21) ◽  
pp. 12941-12962 ◽  
Author(s):  
Xiaojuan Huang ◽  
Zirui Liu ◽  
Jingyun Liu ◽  
Bo Hu ◽  
Tianxue Wen ◽  
...  
Keyword(s):  
Coal Combustion ◽  
Vehicle Emissions ◽  
Motor Vehicle ◽  
Control Strategies ◽  
Vehicle Exhaust ◽  
Motor Vehicle Emissions ◽  
Haze Pollution ◽  
Inorganic Aerosol ◽  
Urban Sites ◽  
Bth Region

Abstract. The simultaneous observation and analysis of atmospheric fine particles (PM2.5) on a regional scale is an important approach to develop control strategies for haze pollution. In this study, samples of filtered PM2.5 were collected simultaneously at three urban sites (Beijing, Tianjin, and Shijiazhuang) and at a regional background site (Xinglong) in the Beijing–Tianjin–Hebei (BTH) region from June 2014 to April 2015. The PM2.5 at the four sites was mainly comprised of organic matter, secondary inorganic ions, and mineral dust. Positive matrix factorization (PMF) demonstrated that, on an annual basis, secondary inorganic aerosol was the largest PM2.5 source in this region, accounting for 29.2–40.5 % of the PM2.5 mass at the urban sites; the second-largest PM2.5 source was motor vehicle exhaust, particularly in Beijing (24.9 %), whereas coal combustion was also a large source in Tianjin (12.4 %) and Shijiazhuang (15.5 %), with particular dominance in winter. Secondary inorganic aerosol plays a vital role in the haze process, with the exception of the spring haze in Shijiazhuang and Tianjin, for which the dust source was crucial. In addition to secondary transformations, local direct emissions (coal combustion and motor vehicle exhaust) significantly contribute to the winter haze at the urban sites. Moreover, with the aggravation of haze pollution, the OC ∕ EC mass ratio of PM2.5 decreased considerably and the nitrate-rich secondary aerosol increased during all four seasons in Beijing, both of which indicate that local motor vehicle emissions significantly contribute to the severe haze episodes in Beijing. To assess the impacts of regional transport on haze pollution, the PMF results were further processed with backward-trajectory cluster analysis, revealing that haze pollution usually occurred when air masses originating from polluted industrial regions in the south prevailed and is characterized by high PM2.5 loadings with considerable contributions from secondary aerosols. This study suggests that control strategies to mitigate haze pollution in the BTH region should focus on the reduction of gaseous precursor emissions from fossil fuel combustion (motor vehicle emissions in Beijing and coal combustion in Tianjin, Hebei, and nearby provinces).

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 Measurements and receptor modeling of volatile organic compounds in Southeastern Mexico City, 2000–2007

2010 ◽  
Vol 10 (18) ◽  
pp. 9027-9037 ◽  
Author(s):  
H. Wöhrnschimmel ◽  
M. Magaña ◽  
W. A. Stahel ◽  
S. Blanco ◽  
S. Acuña ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Mexico City ◽  
Weekend Effect ◽  
Receptor Modeling ◽  
Liquefied Petroleum Gas ◽  
Linear Regression Models ◽  
Vehicle Exhaust ◽  
Source Contributions ◽  
Volatile Organic

Abstract. Ambient samples of volatile organic compounds (VOCs) were measured between 2000 and 2007 in Southeastern Mexico City, quantifying 13 species (ethane, propane, propylene, butane, acetylene, pentane, hexane, heptane, benzene, octane, toluene, nonane, o-xylene). These time series were analyzed for long-term trends, using linear regression models. A main finding was that the concentrations for several VOC species were decreasing during this period. A receptor model was applied to identify possible VOC sources, as well as temporal patterns in their respective contributions. Domestic use of liquefied petroleum gas (LPG) and vehicle exhaust are suggested to be the principal emission sources, contributing together between 70% and 80% to the total of quantified species. Both diurnal and seasonal patterns, as well as a weekend effect were recognized in the modelled source contributions. Furthermore, decreasing trends over time were found for LPG and hot soak (−7.8% and −12.7% per year, respectively, p < 0.01), whereas for vehicle exhaust no significant trend was found.

scholarly journals Measurements and receptor modeling of volatile organic compounds in south-eastern Mexico City, 2000–2007

2010 ◽  
Vol 10 (2) ◽  
pp. 3319-3346 ◽  
Author(s):  
H. Wöhrnschimmel ◽  
M. Magaña ◽  
W. A. Stahel ◽  
S. Blanco ◽  
S. Acuña ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Mexico City ◽  
Weekend Effect ◽  
Receptor Modeling ◽  
Liquefied Petroleum Gas ◽  
Linear Regression Models ◽  
Vehicle Exhaust ◽  
South Eastern ◽  
Volatile Organic

Abstract. Ambient samples of volatile organic compounds (VOCs) were measured between 2000 and 2007 in south-eastern Mexico City, quantifying 13 species (ethane, propane, propylene, butane, acetylene, pentane, hexane, heptane, benzene, octane, toluene, nonane, o-xylene). These time series were analyzed for long-term trends, using linear regression models. A main finding was that the concentrations for several of the quantified VOC species were decreasing during this period. A receptor model was applied to identify possible VOC sources, as well as temporal patterns in their respective activities. Domestic use of liquefied petroleum gas and vehicle exhaust are suggested to be the principal emission sources, contributing together between 70% and 80% to total VOC. Both diurnal and seasonal patterns, as well as a weekend effect were recognized in the modelled source activities. Furthermore, vehicle exhaust emissions showed a decreasing trend over time, with a reduction of about 8% per year.

41. Diffusion Badges as a Long-Term, Low-Level Method of Ambient Air Analysis

2005 ◽  
Author(s):  
K. Parker ◽  
S. Rose-Pehrsson ◽  
D. Kidwell
Keyword(s):  
Ambient Air ◽  
Air Analysis ◽  
Low Level ◽  
Level Method
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