Research An Emission Inventory of Marine Vessels in Shanghai in 2003 DONG-QING YANG,† STEPHANIE H. KWAN,‡ TAO LU,† QING-YAN FU,† JIAN-MIN CHENG,§ D A V I D G . S T R E E T S , * ,| YA-MING WU,† AND JIN-JU LI† Shanghai Environmental Monitoring Center, Shanghai 200030, P.R. China, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, Shanghai Port Administration Center, Shanghai 200120, P.R. China, and Argonne National Laboratory, Argonne, Illinois 60439
We developed an air pollutant emission inventory for marine vessels in the Shanghai Port in 2003. We estimated emissions under cruising and maneuvering conditions based on two categories of vessels: (1) vessels in the Outer Port, which enter the area following notification of the Shanghai Maritime Safety Administration, a division of the Ministry of Communications of P.R. China; and (2) vessels in internal waterways, which enter those waters following notification of the local Port Administration Centers. Vessels in the Outer Port consist of three subcategories: (1) international vessels that are engaged in foreign commerce; (2) domestic vessels traveling along the downstream portion of the Huangpu River; and (3) domestic vessels traveling along the coast. We also estimate emissions from vessels over 1000 DWT operating under hotelling conditions in the Outer Port. In 2003, the total number of calls was approximately 1.3 million, of which 57% is attributed to vessels in internal waterways and 43% to vessels in the Outer Port. Total marine emissions for NOx, SO2, PM, HC, and CO2 in 2003 are estimated to be 58 160, 51 180, 6960, 4560, and 3 012 800 tons, respectively. Emissions are allocated to 1 km × 1 km grid cells for the 129 km × 102 km Shanghai Port study domain.
were 379 million tons and 14.6 million TEU, respectively (14). The amounts of throughput goods and TEU in 2004 were more than two and ten times the amounts in 1995, respectively (14). The opening of the Yangshan Deep Water Port, located 20 miles off the coast of Shanghai in the East China Sea, is expected to accommodate up to 20 million TEU by 2020 (15). The impact of this extensive ship traffic, which generally burns low-quality oil products, on the air quality of Shanghai today and in the future is a serious concern to local regulatory authorities. In this paper, we examine the link between marine activities and air pollutant emissions in the Shanghai Port by developing an emission inventory that takes into account the various types of marine vessels under cruising, maneuvering, and hotelling conditions. We define the Shanghai Port as the area given by the gridded domain shown in Figure 1, which corresponds to the fifth domain of the numerical air quality prediction model operated by the Shanghai Environmental Monitoring Center. Thus, marine emission data can be input into the model for estimating the effects of marine emissions on ambient air quality. Although the entire geographical area of the Shanghai Port is somewhat larger than the gridded domain in Figure 1, we calculate emissions only from marine vessels in the gridded area. The Shanghai Port consists of the Outer Port, indicated by the red routes in Figure 1, and internal waterways, indicated by the blue routes. Vessels in the Outer Port enter the area following notification of the Shanghai Maritime Safety Administration, a division of the Ministry of Communications of P.R. China. Vessels in the internal waterways enter those waters following notification of the local Port Administration Centers. Vessels in the Outer Port consist of three subcategories, based on navigation routes and the locations where cargos are loaded and unloaded: (1) international vessels that are engaged in foreign commerce; (2) domestic vessels traveling along the downstream portion of the Huangpu River (hereafter referred to as vessels along the Huangpu River), which refers to domestic vessels arriving at or departing from waters between the western boundary of Minhang District and Wusongkou; and (3) domestic vessels traveling along the coast, which refers to domestic vessels berthing at or departing from the terminals along the Yangtze River and Hangzhou Bay.
2. Inventory Methodology 1. Introduction Air pollutant emissions from marine vessels have gained increasing attention due to their significant local, regional, and global effects (1-4). Emission inventories have been constructed in order to quantify marine contributions to air pollution (5-10), some of which focus on Asia (11-13). Marine activities, particularly those in Asia, have risen dramatically over the past decade, due to rapidly growing international sea-borne commerce. Since 1995, Shanghai has moved from being the world’s seventh largest to the world’s third largest container shipping port. The amounts of throughput goods and 20-foot-equivalent units (TEU) in 2004 * Corresponding author phone: (630) 252-3448; fax: (630) 2525217; e-mail:
[email protected]. † Shanghai Environmental Monitoring Center. ‡ Georgia Institute of Technology. § Shanghai Port Administration Center. | Argonne National Laboratory. 10.1021/es061979c CCC: $37.00 Published on Web 06/28/2007
2007 American Chemical Society
We develop a marine emission inventory for the Shanghai Port in a gridded domain measuring 129 km north-south and 102 km east-west, with northeastern and southwestern coordinates of 31.85° N, 121.91° E and 30.70° N, 120.83° E, respectively. We estimate marine emissions as annual activity rates multiplied by appropriate emission factors, using equations based on two marine vessel operating modes: (1) vessels operating under cruising and maneuvering conditions, and (2) vessels operating under hotelling conditions. Annual marine emission rates are based on vessel type and weight, engine load, fuel consumption, number of calls, and operation time. Vessels emit various air pollutants, such as nitrogen oxides (NOx), sulfur dioxide (SO2), particulate matter (PM), carbon monoxide (CO), hydrocarbons (HC), and carbon dioxide (CO2). Based on the availability of reliable emission factors, NOx, SO2, PM, HC, and CO2 emissions are calculated in this study. In order to calculate marine emissions in Shanghai, a number of assumptions are made about typical vessel VOL. 41, NO. 15, 2007 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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FIGURE 1. Map of the marine vessel navigation routes in the Shanghai Port. activities. First, it is assumed that international vessels in the Outer Port operate under maneuvering conditions (defined as speed less than 18 knots), since the speed of these vessels is typically lowered below 18 knots when they enter the piloting area. Second, vessels in the Outer Port that travel along the downstream portion of the Huangpu River and along the coast operate at statistically averaged speeds of 8 and 14 knots, respectively; we therefore assume that these vessels also operate under maneuvering conditions. Third, the average engine power of vessels in the internal waterways that do not use auxiliary engines and either berth at or depart from the ports ranges from roughly 100 to 200 hp (maximum tonnage of vessels is limited to 1000 deadweight tonnage (DWT)); these vessels are assumed to operate under cruising conditions. Fourth, vessels weighing less than 1000 DWT operating in the Outer Port and vessels in internal waterways operating under hotelling conditions only use shore power and are assumed to have no emissions. Fifth, auxiliary engines are assumed to operate at medium speed and to use residual oil. Sixth, it is assumed that if vessels in the Outer Port belong to the same vessel type, they also have the same DWT range, regardless of which navigation routes are used. Seventh, we assume that the average load of the main engines is 80% of maximum continuous rating (MCR) for vessels under cruising conditions, 20% for maneuvering, and 20% for hotelling in port (16). Eighth, we assume that the average load of the auxiliary engines is 15% of the MCR for vessels under cruising conditions, 40% under maneuvering conditions, and 20% while berthing in port. Finally, we assume that emissions from boilers, emergency diesel engines, and waste incinerators are relatively small and can be considered negligible. We calculate emissions from auxiliary engines operating under maneuvering and cruising conditions using eq 1:
TAi,g,j,s,a )
∑N
i,g
× Pi,g,a × Hi,j × EFi,j,s,a × Lj,a
(1)
where TA denotes emissions from the auxiliary engine; N is the number of calls; P is the average vessel power; H is the average vessel operation time; EF is the emission factor; L is the average vessel engine load; and g, i, j, s, and a denote 5184
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the vessel size category in DWT, vessel type, vessel operation condition, pollutant species, and auxiliary engine, respectively. We calculate emissions from the main engines of vessels operating under cruising and maneuvering conditions using equations based on either engine power (eq 2) or fuel consumption (eq 3).
TEi,g,j,s,m )
∑N
i,g
× Pi,g,m × Hi,j × EFi,j,s,m × Lj,m (2)
where N, P, H, EF, L, g, i, j, and s are the same as in eq 1, TE denotes emissions from the main engine, and m denotes the main engine.
TEi,g,j,s,m )
∑N
i,g
× Pi,g,m × Hi,j × EFi,j,sfc × EFsfc,s × Lj,m (3)
where TE, N, P, H, EF, L, g, i, j, s, and m are the same as in eq 2, and sfc denotes specific fuel consumption. For most of these vessels, we used eq 2, but for the vessels for which fuel consumption data are available, we used eq 3. It should be noted that, by using emission factors developed by Entec UK Limited (16) (see later discussion), emissions based on engine power and emissions based on fuel consumption are very similar. We estimate emissions from main and auxiliary engines for vessels weighing over 1000 DWT in the Outer Port operating under hotelling conditions using eq 4. Emissions from vessels less than 1000 DWT in the Outer Port and emissions from vessels in internal waterways are neglected, due to vessel use of shore power or batteries under hotelling conditions.
Ta,i,j,s )
∑W
a
× Ha × Pi × EFi,s × Lj
(4)
where T denotes the total emissions, which are calculated based on the main or auxiliary engines; W is the annual amount of throughput goods; H is the average vessel hotelling time per ton of goods; P is the average vessel power; EF is the emission factor, which is different for main and auxiliary
TABLE 1. Emission Factors Used in This Study engine types and pollutants auxiliary enginec
main engine vessel type international
vesselsa
vessels along the Huangpu riverb vessels along the coasta vessels in internal waterwaysb vessels g1,000 ton DWTa
NOx
SO2
PM
CO2
HC
NOx
SO2
PM
CO2
HC
7.4-14.3 (16) 46-66 (16) 10.6-14.3 (16) 65-88 (16) 13.3-13.8 (16)
10.8-13.5 (16) 51-54 (16) 10.8-12.9 (16) 51-54 (16) 12.0-12.1 (16)
2.1-2.3 (16) 9.2-10.6 (16) 2.1-2.4 (16) 8 (17) 1.5 (16)
688-887 (16) 3,179 (16) 688-764 (16) 3,179 (16) 706-716 (16)
0.9-1.7 (16) 5.3-7.8 (16) 1.2-1.7 (16) 2.0-2.9 (16) 0.9-1.5 (16)
14.7 (16)
12.3 (16)
0.8 (16)
722 (16)
0.4 (16)
a The units for main engines are g/kWh. are g/kWh.
b
The units for main engines are kg/ton of fuel consumed. c The units for auxiliary engines of all vessels
TABLE 2. Reclassification of Vessel Types and Matching of DWT with Engine Power
vessel types in the Shanghai Porta
vessel types (excluding barges) based on Entec UK Limited schemeb
vessel types based on Acurex schemec
bulk dry
bulk dry
bulk carrier
heavy/large article cargo bulk dry (cement) multi-use cargo
bulk dry bulk dry bulk dry/oil
bulk carrier bulk carrier bulk carrier
dredging other activities general cargo (Outer Port)
dredging other activities general cargo
general cargo
container
container
container
chemical refrigerated cargo RORO
chemical refrigerated cargo RORO
container refrigerated cargo RORO
passenger/RORO
passenger/RORO
RORO
liquefied gas other liquid oil
liquefied gas other liquid oil
tanker tanker tanker
chemical /oil
oil
tanker
passenger high-speed passenger vehicle/passenger towing/pushing (Outer Port) outboard engine barge general cargo (internal waterways) towing/pushing (internal waterways)
passenger passenger passenger towing/pushing other bulk dry -
passenger passenger passenger -
DWT ranged (1000 ton)
vessel callsd (%)
avg. LMIS bhp or empirical hpe
0-25 26-50 51-75 >75 >75 3-5 0-25 26-50 51-75 >75 1-3 1-3 0-25 26-50 51-75 >75 0-25 26-50 51-75 1-3 1-3 0-25 26-50 51-75 >75 1-3 1-3 0-25 26-50 51-75 >75 2-2.5 -
64 29 3.7 2.9 100 100 64 29 3.7 2.9 100 100 95 3.3 1.8 0.3 76 24 0.4 100 100 95 3.3 1.8 0.3 100 100 61 32 5.9 1.0 100 100 100 100 100 100 100 100
9,123 11,306 12,508 19,695 35,008 8,143 9,123 11,306 12,508 19,695 8,143 8,143 6,389 12,988 16,870 35,008 14,411 27,244 40,636 8,000 5,832 23,455 34,987 34,987 34,987 5,894 5,894 8,867 13,546 15,752 20,699 2,500f 20,544 100f 2,000f 80f 0 272f 100f
a The 24 vessel types are based on statistical data from the Shanghai Port Administration Center (19). b Emission factors are derived from Entec UK Limited (16), based on the 16 vessel types. c Average LMIS bhp data are derived based on the seven vessel types used in the Acurex report (17), except for the vessels for which empirical data were available. d DWT range data and the percentage of calls for different vessel types are based a 1998 study of marine emissions in the Shanghai Port e Engine power data are from the Acurex report (17) or experts’ opinions. f The data are from experts’ opinions.
engines; L is the average vessel engine load, which is different for main and auxiliary engines; and a, i, j, and s indicate the terminals, vessel type, vessel operation conditions, and pollutant species, respectively.
2.1 Emission Factors. Emission factors are taken directly from or are adapted from two detailed marine activity studies (16-17), as indicated in Table 1. The emission factors, except for PM emissions from vessels in internal waterways operating VOL. 41, NO. 15, 2007 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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TABLE 3. Fleet Profile for the Shanghai Port by Numbers of Calls in 2003a vessels in the Outer Port
vessel type
international vessels
vessels along the Huangpu River
vessels along the coast
vessels in internal waterways
bulk dry bulk dry (cement) chemical chemical/oil container dredging general cargo outboard engine heavy/large articles cargo high-speed passenger liquefied gas other liquid barge multi-use cargo oil passenger passenger/RORO vehicle/passenger refrigerated cargo RORO towing/pushing other total numbers of calls
1,972 1,224 15,112 4,452 72 349 721 160 90 431 125 195 24,902
5,122 2,680 19,336 147,859 8,896 48,050 3,131 63,413 1,886 24,428 20,912 80,821 9,763 12,025 448,322
5,301 1,446 89 4,352 565 31,005 20 9,870 2,704 6,706 1,162 2,787 9915 75,922
406,620 277,837 30,847 15,678 730,982
a The numbers of calls are derived from statistical data according to the Shanghai Port Administration Center, which may be different from actual vessel activity.
under cruising conditions, are taken directly from the Entec UK Limited database (16). The PM emission factor for vessels in internal waterways operating under cruising conditions is derived from Acurex Environmental Corporation (17). The Entec UK Limited emission factors (16) for the year 2000 are based on vessel types defined by the Lloyd’s Marine Intelligence Unit (LMIU), which consist of five types of engine and three types of fuel for various operating conditions. The range of emission factors for NOx, SO2, CO2, HC, and PM, as shown in Table 1, accounts for the variety of vessel types present in the Shanghai Outer Port and internal waterways. Entec UK Limited emission factors for SO2 (16) were developed under the assumption that all sulfur in the fuel is converted into SO2 during combustion. It was also assumed that there is 0.5% sulfur in marine gas oil, 1.0% in marine diesel oil, and 2.7% in residual oil (16). Lavender (18) also estimated the sulfur content of heavy (marine gas) oil and residual oil to be 0.5% and 2.7% by weight, respectively. The Acurex emission factor for PM from vessels in internal waterways (17) is 8 kg of PM emitted per ton of fuel consumed. 2.2 Vessel Types. According to the Shanghai Port Administration Center, there are 24 vessel types in the Shanghai Port (19). We re-classify the vessel types according to the Entec UK Limited database, which is based on LMIU vessel types. The 16 Entec UK Limited vessel types present in the Outer Port operating under cruising and maneuvering conditions are as follows: liquefied gas, chemical, oil, other liquid, bulk dry, bulk dry/oil, general cargo, dredging, container, refrigerated cargo, roll-on/roll-off (RORO), passenger/RORO cargo, passenger, towing/pushing, other bulk dry, and other activities. It should be noted that barges in the Shanghai Port are not equipped with engines and, therefore, are assumed to have no emissions. Vessel types in internal waterways are divided into four types according to statistical data: barge, towing/pushing, general cargo, and outboard engine vessels. The re-classification of vessel types is shown in Table 2. Hotelling vessels weighing more than 1000 DWT are categorized into four types based on statistical data 5186
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according to the type of cargo transported: general cargo, bulk dry, liquid, and container. Size categories are assigned by DWT. 2.3 DWT Range, Registered Calls, and Engine Power. On the basis of marine activity statistical data from 1998 and experts’ opinions, we match the re-classified vessel types based on the Entec UK Limited database with the DWT ranges shown in Table 2. Acurex (17) determined values for the relationship between vessel design category, corresponding vessel DWT category, average LMIS BHP, brake-specific fuel consumption (BSFC), and cruising fuel consumption for the seven vessel types: bulk carrier, general cargo, container, refrigerated cargo, RORO, tanker, and passenger vessels, as shown in Table 2. We apply the DWT-average LMIS BHP values for these seven vessel types to the other vessel types identified in the Shanghai Port, according to the similarity between the DWT of the other vessel types and the types in the Acurex report, except for the vessel types for which we can get empirical data. Note that the data of average LMIS BHP, brake-specific fuel consumption (BSFC), and cruise fuel consumption for the seven vessel types are for main engines. For the engine power from auxiliary engines, we use data from the Acurex report. It is assumed that the average auxiliary engine power values for different vessel types are 750, 1250, and 1000 kW under cruising, maneuvering, and hotelling conditions, respectively. For vessels in internal waterways, fuel consumption is based on the local experts’ opinions. The average engine power of vessels not equipped with auxiliary engines that operate in the internal waterways ranges from roughly 100 to 200 hp (maximum tonnage of vessels is limited to 1000 DWT). The numbers of calls made by each vessel type in each DWT range are calculated according to the number of calls made in the various shipping routes and to the proportion of vessels, as shown in Tables 2 and 3. 2.4 Traveling Distance and Operation Time. To calculate the distance traveled, we used MapInfo Professional version 7.0 to process the spatial information. In the Outer Port, the
3. Emission Estimates According to statistical data, approximately 1.3 million calls were made in the Shanghai Port in 2003. Vessels in internal
0.378 682.06
0.018 0.029 0.008 0.017 32.94 52.38 13.64 30.98
6.20 39.57 44.27
1.57 6.66 2.72 9.17 1.72 7.66 3.02 10.38
0.19 0.83 0.50 1.14
0.51 0.42 0.03 24.84 0.014 8.89 7.44 0.48 436.80 0.242 1.84 1.54 0.10 90.48 0.050 It is assumed that they are not equipped with auxiliary engines 0.23 1.62 0.49 0.06 100.06 756.10 223.20 68.72 0.33 2.40 0.72 0.09 1.69 12.84 3.76 1.16
CO2 SO2
main engine
92.46 0.12 0.67 0.56 0.04 391.60 0.56 1.07 0.89 0.06 160.38 0.34 0.28 0.23 0.02 538.20 0.76 0.63 0.53 0.03 It is assumed that they use shore power and have no emissions It is assumed that they use shore power and have no emissions 2330.7 4.18 13.89 11.61 0.76 Total
For vessels operating under hotelling conditions, the operation time is determined based on statistical data on the amount of throughput goods and the turnover speed of the goods per day.
cruising hotelling
Operation time ) average navigation distance/navigation speed (5)
TABLE 5. Marine Emissions in the Shanghai Port in 2003 (1000 Tons)
distance is obtained directly, based on vessel navigation course maps of the Shanghai Port provided by the Shanghai Port Administration Center. For the distance in internal waterways, we developed a topological relationship between the different areas and rivers to obtain the distance traveled. This relationship is based on the following assumptions: (1) that the terminals are evenly distributed along the vessel navigation routes; and (2) taking vessels traveling to different terminals into consideration, that half of the total navigation length is the average distance traveled. These data are also used to determine the spatial distribution of emissions by allocating the emissions to 1 km × 1 km grid cells. Forty individual terminals are identified in the Shanghai Port, of which 14 are used by international vessels, 7 are used by vessels along the Huangpu River, 9 (one of which was not in operation in 2003 and thus is not included in our inventory) are used by vessels along the coast, and 11 are used by vessels in the internal waterways. The operating speeds of vessels are determined by vessel types, shipping routes, and the locations of terminals that the vessels berth at or depart from. Vessel operating speeds are based on empirical data found in Table 4. For the vessels in the Outer Port, it is assumed that they operate under maneuvering conditions. Therefore, the operating speeds given in Table 4 for vessels in the Outer Port are those for maneuvering conditions. According to a local navigation rule, the maximum vessel speed must be less than 4 knots in the internal waterways. For vessels operating under cruising and maneuvering conditions, the operation time is calculated according to eq 5:
HC
a There are four vessel types in the internal waterways: general cargo, barge, towing/pushing, and outboard engine vessels. It is assumed that barges have no emissions.
1.97 13.64 4.12 1.76
4 4 4
international vessels vessels along the Huangpu river vessels along the coast vessels in internal waterways vessels in the Outer Port > 1000 DWT general cargo bulk dry liquid container vessels in the Outer Port < 1,000 DWT vessels in internal waterways
8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8
maneuvering
15 12 13 13 12 12 15 15 15 15 15 12 15 12 12 13 8
CO2
18 13 15 15 12 12 18 18 20 18 20 12 18 12 12 15 -
PM
container general cargo bulk dry bulk dry/oil chemical oil RORO dredging passenger other bulk dry passenger/RORO towing/pushing refrigerated cargo liquefied gas other liquid others outboard engine
SO2
internal waterwaysa
NOx
Huangpu River
PM
Yangtze River
NOx
Hangzhou Bay
vessel type
vessel type
operation mode
cruising
auxiliary engine
maneuvering
engine types and pollutants
vessels in the Outer Port
vessels in internal waterways
HC
TABLE 4. Assumed Average Operating Speed (Knots)
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TABLE 6. Summary of Marine Emissions in the Shanghai Port in 2003 (1000 Tons) classification
NOx
SO2
PM
CO2
HC
vessel navigation routes outer port internal waterways total
56.40 50.02 6.87 2,944.06 4.50 1.76 1.16 0.09 68.72 0.06 58.16 51.18 6.96 3,012.78 4.56
engine type main engine auxiliary engine total
44.27 39.57 6.2 2,330.72 4.18 13.89 11.61 0.76 682.06 0.38 58.16 51.18 6.96 3,012.78 4.56
vessel operating conditions cruising 1.76 1.16 0.09 68.72 0.06 maneuvering 30.97 27.69 4.06 1,631.47 2.65 hotelling 25.43 22.33 2.81 1,312.58 1.85 total 58.16 51.18 6.96 3,012.78 4.56
waterways make up 57% of total calls, 35% are from vessels along the Huangpu River, 6% are from vessels along the coast, and 2% are from international vessels. Container, general cargo, and bulk dry goods vessels make up over 86% of the international vessels, while the other vessel types make up less than 14%. General cargo vessels represent the largest fraction of vessels along the Huangpu River, along the coast, and in the internal waterways, constituting 33%, 41%, and 56%, respectively, of total vessels. Other major vessel types found in the three regions are passenger/vehicle cargo, highspeed passenger cargo, and outboard engine vessels. Emissions from vessels in the Shanghai Port are summarized in Tables 5 and 6. Emissions from vessels in the Outer Port account for more than 97% of total emissions for NOx, SO2, PM, HC, and CO2; emissions from vessels in internal waterways account for
FIGURE 2. Spatial distribution of NOx, SO2, PM, CO2, and HC emissions from marine activities in the Shanghai Port. Values in parentheses indicate the number of grid cells in the respective emission ranges. 5188
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TABLE 7. Comparison of Marine Emissions in the Shanghai Port and the Los Angeles Port source category total ocean-going vesselsa harbor craft cargo handling equipment railroad locomotives heavy-duty vehicles total a
NOx 58,160 6,923 3,531
SO2
PM
PM10
PM2.5
CO2
HC
427
3,012,780 -
4.56 -
178
164
-
-
103
-
-
Shanghai Port (2003) (tons/yr) 51,180 6,960 4,118 539 -
506
1,863
44.1
LA Port (2001) (tons/yr) (20) 112
2,466
89.8
-
60.1
55.2
-
-
4,464
33.6
-
87.9
77.9
-
-
-
-
19,245
4,791
-
970
826
In the baseline year of 2001, 769 vessels made a total of 2717 OGV inbound calls to the L.A. Port.
only 3% of the total, even though the number of calls is much higher in the internal waterways than in the Outer Port. Vessels along the Huangpu River, which account for 35% of total calls, contribute the largest fraction of Outer Port emissions, and the ratio to emissions from the Outer Port is as much as 39%. Vessels over 1000 DWT operating under hotelling conditions contribute 44% of NOx, SO2, and CO2 emissions, and 40% of PM and HC emissions, which are less than those operating under cruising and maneuvering conditions. Emissions from auxiliary engines are less than those from main engines. Emissions of HC and PM from main engines are as much as 92% and 89% of total emissions, respectively. For NOx, SO2, and CO2, the percentages of emissions from the main engines compared to total emissions are similar, at 76-77%. Spatial distributions of NOx, SO2, PM, HC, and CO2 from marine vessels are shown in Figure 2, for which marine emissions are allocated to 1 km × 1 km grid cells for the Shanghai Port domain. Emissions from vessels along the Huangpu River constitute the largest fraction of emissions from cruising and maneuvering vessels in the Shanghai Port, evident in Figure 2 as the region with the highest emission rates for all species. Groups of grid cells along the coast, which indicate the locations of ports, are shown to have higher emission rates than other areas along the coast since total emissions at the ports include emissions from vessels under hotelling conditions in addition to vessels under maneuvering and cruising conditions. Due to the differences in marine activities and in the scope of marine emission research domains, it is difficult to conduct an in-depth comparison between marine emissions in Shanghai and in other major world ports. In the Los Angeles (L.A.) Port, for example, emissions of NOx, SO2, PM10, and PM2.5 in 2001 were 19 200 tons, 4800 tons, 970 tons, and 830 tons, respectively (20), as shown in Table 7. (PM10 and PM2.5 are those components of PM that are e10 microns and e2.5 microns in diameter, respectively.) In the L.A. Port, the largest proportion of emissions come from ocean-going vessels (OGVs); however, in the Shanghai Port, the vessels along the Huangpu River represent the largest contributor to total emissions from marine vessels. Differences are likely due to the following: (1) the study of marine emissions in the L.A. Port utilizes different emission source categories and a different vessel classification scheme; and (2) marine activity parameters, such as the distance traveled and the number of calls, play an important role in determining resulting marine emissions, and the patterns of marine activity by international and local vessels in Los Angeles and Shanghai are very different. As shown in Table 8, emissions from all sources in Shanghai (from the project “The methodology research of
TABLE 8. Emissions from Marine Vessels and All Sources in Shanghai in 2003 (1000 Tons) marine pollutant marine vessels other sourcesa all sourcesa share (%) NOx SO2 PM CO2 HC a
58.2 51.2 7.0 3,012.8 4.6
374.5 486.8 480.2 NA NA
432.7 538.0 487.2 NA NA
13.4 9.5 1.4 NA NA
From (14).
establishing an air pollutant emission inventory in Shanghai”) ranged between 0.43 and 0.54 million tons in 2003 (14). Marine emissions comprise as much as 13.4% of total NOx emissions and 9.5% of total SOx emissions from all sources, therefore representing an important contributing source category for these pollutant species.
4. Sources of Uncertainty The accuracy of our emission inventory is dependent upon the input data used and the assumptions made. In our study, the number of calls is derived from statistical data provided by the Shanghai Port Administration Center, and the navigation routes are digitized according to navigation maps. As for vessel speed, fuel consumption estimates for some vessel types are from empirical data. The uncertainty of the emissions data arises primarily from the following: (1) the applicability of the emission factors to Shanghai, which are based upon the OGVs specific to the Entec UK Limited study; (2) the relationship between DWT and engine power; (3) the relationship between DWT and the number of calls; (4) the amount of auxiliary engine power; and (5) engine load, which changes during different vessel activities and operating conditions. The areas with the highest emissions for all species are primarily distributed along the Huangpu River and are more concentrated at ports located along the coasts bordering the Yangtze River and Hangzhou Bay. Further work is needed to address the magnitude of uncertainties, to expand the domain under study, to acquire and use higher-resolution input data, and ultimately to model the impacts of marine emissions on local and regional air quality. Continued expansion of the Shanghai Port in the future ensures that this will be an important emission source category in need of vigilant attention.
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Received for review August 17, 2006. Revised manuscript received April 30, 2007. Accepted May 17, 2007. ES061979C
