Emission load analysis of land transportation on urban roads in Jember regency, Indonesia (a case study of Sultan Agung Road)

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Introduction
Sultan Agung Road is a national road in Jember Regency.The road is busy because it is included in the urban area, trade routes and urban traffic.According to [1], busy vehicle activities will cause air pollution due to vehicle exhaust emissions.The main pollutants caused by vehicle activity are CO, HC, NO 2 , PM 10 , CO 2 and SO 2 .Pollution due to vehicle exhaust gasses can cause respiratory infection.The relationship between PM10 concentration and Covid-19 has been evident in [2] of which the authors found SARS-CoV-2 RNA in PM10 samples in Bergamo, Italy.In addition, CO2 is a major greenhouse gas that drives the global warming.To reduce the impact of the global warming, Indonesia in the Enhanced Nationally Determined Contribution (NDC) has pledged emission reductions of 31.89%unconditionally and 43.20% conditionally by 2030 [3].The objective of this study is to estimate the amount of emission load due to vehicle exhaust gasses on Jalan Sultan Agung Jember and to propose the best emission load reduction strategy with the novelty of this study compared with previous studies is related to the identification whether there is a statistically significant difference among the number of counted motorcycles in weekdays and weekend morning by using repeated-measure ANOVA.We hope the proposed strategy can be considered by the local government as one of the ways to reduce the emission in Jember and further contribute to the fulfilment of the Indonesian NDC.

Data retrieval
This research uses secondary data such as emission factors from Indonesian Ministry regulations and the 2006 IPCC Guidelines [4][5][6].The primary data were the numbers and types of motorized vehicles, obtained from CCTV data recorder combined with manual counting.

Data collection
The data of the number of vehicles were collected at Sultan Agung Road, Jember Regency.Data collection for manual counting was carried out in October and November.Meanwhile, CCTV data in September.The sampling time was conducted every day in the peak hours of morning (06.00-08.00),afternoon (11.30-13.30),evening (15.30-17.30),and night (18.30-20.30)for 2 hours each.

CO, HC, NO2, PM10 and SO2 emission calculation
Data on the number of vehicles that have been obtained are analyzed by referring to [4] in which the emission load was calculated based on the formulas in equations 1 and 2:  = ∑ ( , ×  ,, × 10 −6 ) , =1,=1 (1)  , =  , ×   (2) Where: Ea = Emission load for a pollutant (ton/years) VKTb,c = The total length of trips for b category motorized vehicle by using type C fuel (km) FEa,b, c = Emission factor (g/km) a = Types of pollutants (1-6 for CO, NO2, HC, PM10, SO2, CO2) b = The category of motor vehicles c = Types of fuel (1-2 for gasoline and diesel) fb,c = The number of vehicles VKTc = Road length (km)

CO2 emission calculation
The calculation of CO2 emissions refers to [7] for the values of emission factors.Emission calculation is obtained from the sum of CO2, CH4 and N2O emission values.The CH4 and N2O emission values are converted into CO2 by multiplying them by the conversion factor.
Where: Emissions = Mass of CO2 emitted Fuela = Mass or volume of fuel combusted EFa = CO2 emission factor per mass or volume unit (kg gas/TJ) a = Types of fuel (gasoline or diesel) = Emission load for a pollutant (ton/years) According to [6], CO2 emission factors per mass or volume unit are 72.600kg gas/TJ for gasoline and 74.300 kg gas/TJ for diesel.The fuel consumption calculation stage begins with knowing the value of road length, number of vehicles, fuel density, fuel economy and heating value of motor vehicle fuel.The calculation formula for the energy consumption stage is contained in equations 4, 5 and 6 below.

Emission reduction strategy using AHP method (Analytic Hierarchy Process)
The Analytical Hierarchy Process (AHP) method was used in prioritizing the predetermined scenarios [8].The use of questionnaires was carried out with expert respondents from related agencies such as the Jember Regency Transportation Office.The questionnaire data was then processed using R [9] and RStudio [10] to get the results and conclusions on the scenario of reducing land transportation sector emissions on Jalan Sultan Agung Jember.
The criteria for emission reduction scenario were Environmental, Technical and Financial aspects.Three strategies, namely Smart Driving, the use of Solar Cell in public street lighting and BRT (Rapid Transit Bus) Operational Development, were proposed in the AHP questionnaires.

Number of Motorized Vehicles
The number of motorized vehicles on Jalan Sultan Agung is reported in Table 2.It is found that the day with the largest number of vehicles was Friday, with motorcycle vehicles as the dominant category.Sunday has the lowest number of vehicles.According to [11], the number of vehicles in the Karees area, Bandung is very high on weekdays, this is related to community activities in the area such as office, school, commercial activities, and so on.Meanwhile on Sunday, the vehicle activity is quite low.This is because some residents prefer to spend their time resting at home and many vehicles with out-of-town plates were found on that day.The number of vehicles tends to be high on Tuesdays.This is because many community activities are carried out on weekdays [12].
Table 1.Average number of motorized vehicles per year (units/year).

Motor vehicles category
The average number of motorized vehicles per years (unit/years)  The motorcycle accounts for more than 60% of total vehicle units.Hence, it is worthy of a deeper observation.Figure 1 shows the counted numbers of motorcycles during 6 a.m. to 8 a.m. from mid-September to mid-November 2022.Compared to weekdays, weekends show considerable declines in the number of motorcycles.Based on repeated-measure ANOVA by using nlme package in R [13], we found that there is no statistically significant difference among the number of counted motorcycles in weekdays (Monday to Friday) morning from 6 a.m. to 8 a.m.(χ 2 (4) = 8.70, p-value = 0.691).We found a significant difference between weekday mornings and weekend morning in the counted motorcycles (χ 2 (6) = 474.74,p-value < 0.0001).

CO, HC, NO2, PM10, CO2 and SO2
Emission calculations are based on the CO, HC, NO 2, PM10, CO2 and SO2 emission calculation formulas.The calculation of CO2 emissions is based on equation 3, while other than CO2 is based on equations 1 and 2. The results of emission calculations are shown in Table 3.The tables show that the highest emission value varies.The lowest emission value for all emissions is the same on Sunday.CO, HC and PM10 emissions are highest on Tuesday.NO2 and CO2 emissions are highest on Friday.Meanwhile, SO2 emissions are highest on Saturday.The difference is caused by the various values of emission factors and the number of vehicles of each motor vehicle.The number of vehicles, fuel consumption and the emission factor influence emission load calculation result [14].According to [15], the difference in emission rates for each way is caused by a difference between the number of vehicles and the emission factor of the vehicles.PM10 concentration is said to be low even though the number of vehicles at one point is greater than at another point because the emission factor of these vehicles is small [16].

Emission Reduction Strategy Analysis Results
Nine respondents were selected in this study to fill AHP questionnaires.The respondents represent stakeholders, namely the Environmental Agency (DLH), the Jember Regency Transportation Agency, lecturers, and the local community.The results of the assessment of each respondent are presented in Table 4.   4 shows that respondents 1, 2, 3 preferred the smart driving strategy most, whereas the respondents 4, 5, 6, 8 and 9 preferred the Rapid Transit Bus (BRT) strategy.Respondent 7 preferred the diesel oil Cell strategy.The Geometric Mean (GM) was used to get the mean values.The results of the Geometric Mean (GM) value are then normalized to make it easier to compare the percentage value and determine the ranking of emission reduction strategies.The results of the normalized value of strategies from all respondents show a value of 0.470 for Rapid Transit Bus (BRT), diesel oil Cell of 0.299 and 0.231 for Smart Driving.The order of priority ranking is Rapid Transit Bus (BRT), Solar Cells and Smart Driving.

Conclusion
Based on the results of the research, we conclude that the emission burden generated from the land transportation sector on Jalan Sultan Agung Jember Regency includes 177.486 tons of CO/year; 48.638 tons of HC/year; 9.481 tons of NO2/year; 2.534 tons of PM10/year;

Table 3 .
AHP Scores by All Respondents.

Table
1,245.15 tons of CO2/year and 0.421 tons of SO2 / year.The recommended strategies for emission reduction on Sultan Agung Street in Jember Regency are Smart Driving, Use of Solar Cells on Public Street Lighting, and Development of BRT (Rapid Transit Bus) Operations.Based on the Analytic Hierarchy Process (AHP), BRT Operational Development (Rapid Transit Bus) should be given the highest priority, followed by using Solar Cells in Public Street Lighting and Smart Driving.