Transport externalities of bus stations produced by Greenhouse Gas (GHG)

. It is established that the interprovincial transportation in bus terminals of the Cities such as Ambato, Riobamba, Salcedo, Latacunga and Guaranda have contributed to the build-up of external costs of Greenhouse Gases (GHG) The climate change costs are calculated by multiplying the carbon emissions by the cost factor. To quantify the GHG emissions, this study has taken into account of both the direct and indirect sources of the Greenhouse Gas Protocol (GHG), as well as the ISO 14064.1: 2006 standard. In view thereof, it was found that the 11 bus terminals of the five cities, namely Latacunga, Riobamba Salcedo, Ambato, Guaranda-which accounts for around 3225 buses, had accounted for the emissions of 25,746.8 tCO 2 eq, 37,404.6 tCO 2 eq, 8,762.7 tCO 2 eq, 92,364.9 tCO 2 eq, 31,990.3 tCO 2 eq, respectively. Simply, the average load of such pollution produced per vehicle was 60.8 tCO 2 eq. and the total emissions were 196,269.3 tCO 2 eq with an estimated GHG contamination cost of €27,477,702 per year.


Background
Externalities are created when the final product production, the expected good or service and the associated pollutant emissions, produces a negative effect on another agent without receiving any compensation [1]. In other words, this produces a loss of social wellbeing due to lack of contaminant-free air.
In Latin America, direct climate change transformations have been observed whereby, the temperature is increasing at the rate of average of 0,1°C every ten years because of the Greenhouse gas emissions (GHG) [2]. This is forcing countries to take measures by prioritizing social sectors so that problems can be mitigated ; issues such premature deaths of more than two million people per year [3] and also the costs generated by non-pollution efforts Current bus transportation needs require the use of heavy vehicles that move continuously that run on the diesel engines. [4] The use of this type of vehicle has produced quite an impact on the environment by emitting pollutants into the air. [5]. The transportation sector has a direct impact on the accelerated growth of greenhouse gas (GHG) emissions, which cause climate change. [6].
The interprovincial bus stations infrastructures have met the requirements to satisfy the needs of the embarkation and disembarkation passengers [7]. Yet, these activities have accumulated GHG emissions from direct and indirect sources polluting the environment as a result. Once the emissions are quantified, thereby identifying the most relevant sources can the areas of emission reduction and efficiency increase can be prioritized.
The climate change externalities' costs can be calculated by multiplying the emissions of carbon dioxide equivalent in tons of one year (tCO2eq) by a cost factor. First, it is necessary to determine (CO2) carbon dioxide emissions, (NOx) nitrogen oxides and (CH4) methane according to the Greenhouse Gas Protocol (GHG) guidelines and the ISO 14064.1: 2006 standard.
In market economies where the economic resources' scarcity is not clearly shown, the direct quantification of these externalities is estimated by policymaker asking for a value to be paid in favour of environmental improvement or a compensation [8]. The estimation methodology for the non-contamination cost calculation which is used to consider the costs of goods through its used or unused economic value, and the determination of the externality economic value has become an essential part of the socioenvironmental economy in business activities [9].
As the Ecuadorian highlands bus stations agglomerate a significant number of buses, people and resource consumption resulting in the generation of GHG its pollution costs will, therefore, be analysed.

Methodology
The methodology is illustrated in the flow chart in figure 1.

Greenhouse Gas (GHG) measuring equipment
The Bacharach ECA 450 analyzer was used to measure the efficiency of combustion gases and environmental emissions, (see figure 2) following the methodology of Boruta, Imiolek (Boruta et al., 2013). This equipment measures and displays the oxygen percentage (O2) and the concentration of carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO2) of flue gases.

Sample Size Determination
A stratified sample was computed [10] with proportional fixation to separate the pollution into exclusive segments, in which the homogeneity and minimum variance are analyzed. For this investigation, a sample of 3225 buses with a 95% confidence level is considered. Later, the sample was then classified according to the European Emission Standard by considering the manufacture year. See table 1.

Calculation of GHG emissions
To begin with, according to the EURO standard (TOTAL, 2015), the land transport classification by city has three categories: EURO I, EURO II, EURO III. For the gas emissions quantification, (Galarza Baldeón, 2016) -1: 2006 It will carry out the following actions: define limits, select the base year, identify the emissions and finally quantify the emissions using the Greenhouse Gases Protocol (GHG).

Calculation of direct GHG emissions (scope I)
GHG emissions which generated by vehicles in the bus stations are considered. [12].

Calculation of indirect GHG emissions (scope II)
Under this scope, GHG emissions generated by bus stations' energy consumption are established. The data collection method is used for scope II emissions [13] according to figure 3.

Calculation of indirect GHG emissions (scope III)
With regard to this area, those GHG generation sources which do not belong to this case study, (such as the interprovincial transport buses occupying the bus station), are considered. [14]. To proceed, the main data such as the manufacture year, service operator brand and name are vital.
Following the quantification methodology (see figure 4) and according to the GHG protocol, it is necessary to know: the type of fuel, the amount of fuel consumed and price.

CO2 carbon dioxide emission factor
It starts by determining the% CO2 and applying equation 1.

GHG emission calculation
The GHG emission considering both direct and indirect sources is calculated with equation (6): Where: EGEI= GHG emission (tCO2) DA= activity data (TJ) Considering the potential of global warming [17] The total emissions in tons of CO2 equivalent to a year CO2-eq are determined with the equation (7).

Calculation of the externality cost due to GHG emissions
From the recommended values to the calculation of the global warming cost, the most commonly used methods recommend to consider the values between 1 €/tCO2 and 140 €/tCO2. Although the most used methodology considers the avoided costs, the estimation hypotheses are very sensitive. In fact, there are already many considerations such as the discount rate, the potential for impact, the function of the damage, the pace of climate change, the impacts on the ecosystem. In other words, for the consideration of the damage aggregation, the shadow cost will be considered [18], not only because its value does not give intervals, but also this is the most updated data.
Lastly, the shadow pricing methodology is used to estimate a comparison point among the costs obtained in the countries of the European Community, which uses the value of 140€/tCO2 [19] Table 2 shows the total emission factor by city. Although the city of Salcedo did not have a large number of vehicles compared with the other cities in the study, it has, however, recorded a higher emission factor value. Table 3 illustrates the CO2 emissions in tons. (tCO2) by cities. It is considered 851,4 Kg/m 3 as the diesel density and 0,04 TJ/t as the calorific value of diesel [20].

Results of total emissions by category
In table 4 is presented the CO2 emissions in tCO2-eq from each city.   Table 6 illustrates the CO2 emissions in tCO2-eq for each city. Guaranda 31.990,3

Cost results for GHG in bus stations
In

Conclusions
From the results by scope of 5 cities having 11 bus stations, it is observed ranges between 99.99% to 99.62% of tCO2-eq global emissions for Scope III. Nonetheless, there are some other modern factors which might increase this emission factor; as can be seen in old cars or busses, which are not functioning according to international standards. Moreover, altitude can also be another factor that increases CO2-eq. In the central area of Ecuador, the global GHG emissions reports was 196.269,3 (tCO2-eq). The said value was higher in interprovincial buses from Ambato and Riobamba, accounting for 99.99%. Similarly, the previous result is compared to the amount of (tCO2-eq) generated by electricity consume of approximately 220,480.1 Ecuadorian individual houses per year.
The GHG pollution cost is 27.477.702 € per year. The 2018 external costs of the bus stations are estimated to represent 30,2 % of Gross Domestic Product (GDP) of Ecuador. Surprisingly, this figure exceeds in 10.2% in similar studies that were conducted in Euskadi -Europe [22]. The externality total cost data is required to compare with the European GDP percentage.