Example Inventory 6 Source Group 5 Transport

Country X prepares its first inventory of dioxins and furans in 2006 to support the development of the action plan as required by Article 5 of the Convention and included in the National Implementation Plan pursuant to Article 7. Activity data for the different sources of PCDD/PCDF in country X were collected for the reference year 2004 (baseline year). The inventory is developed by applying the Toolkit 2005 methodology and the emission factors specified in that version of the Toolkit.

All four source categories included in this source group are relevant for country X in the baseline year. These are presented below.

According to the Toolkit 2005 methodology, activity rates for transport should be expressed as volumes of fuel used by category of fuel and transport. During the process of activity data collection, information on actual amounts of fuel used in the transport sector annually (gasoline, ethanol, diesel fuel, kerosene, residual oil, jet fuel etc.) at the national level was found from the national statistics office. According to these data, in 2004 in country X, 1,000,000 tons of gasoline, 500,000 tons of diesel fuel, 100,000 tons of heavy fuel (residual) oil, 50,000 tons of kerosene, 10,000 tons of LPG and 5,000,000 m³ of CNG were used for transportation. The data provides details on quantities of fuel according to fuel type and sector (road transport, railway transport, mobile machinery in agriculture, construction, forest industry etc.).

However, no data on distribution of leaded and unleaded gasoline are publicly available; no data on distribution of fuel consumption according to the type of vehicles (4-stroke and 2-stroke) and its ecological class (without catalyst and with catalyst) are available.

To complement this information and be able to obtain estimates of fuel distribution with a higher degree of confidence, questionnaires have been sent to the main offices and consumers of fuel in the country: Ministry of Transport, Ministry of Trade, Police Agency, Railroad agency, Aviation Company. The objectives of the questionnaires were to obtain more detailed data on the vehicle fleet.

It was thus established that data are available on request on the number of registered vehicles per type of vehicle. Data on the year of production of the registered cars were also obtained, but no account of vehicles by ecological characteristics (with or without catalysts) was available.

According to these data obtained by the developer of the inventory, 100,000 tons of leaded gasolinewere imported in 2004, but the distribution between 4-stroke and 2-stroke vehicles could not be obtained. Questionnaires showed that 2-stroke vehicles are more often fueled with leaded gasoline in comparison with 4-stroke vehicles; expert judgment was used to estimate the distribution of leaded gasoline between 4-stroke and 2-stroke vehicles; this was assumed to be 80%:20%. For the distribution of fuel per type of vehicle, proxies were estimated by using data on the number of registered cars according to the type and the specific fuel consumption per unit.

For the distribution of vehicles according to ecological characteristics, data on the age of vehicles were used. It was assumed that vehicles which comply with Euro 2 class and higher are equipped with catalysts. It was assumed that vehicles imported from the European Community comply with the highest Euro class which was in force at the time of the vehicle production. Further, questionnaires allowed to estimate the distribution of vehicles according to the year of production, and through this - between Euro classes.

The amount of gasoline consumed was then distributed between 4-stroke and 2-stroke engines according to number of vehicles in a category, and averaged specific consumption of fuel per vehicle type was of 95 and 5%.

All diesel fuel engines were assigned to category 5c – Diesel engines, including light and heavy duty vehicles, railway transport, construction, agricultural and other mobile machinery.

The corresponding 2005 Toolkit emission factors were applied to these four source classes, and release estimates obtained by multiplying the activity rates with the emission factors. The results are presented in the table below. No PCDD/PCDF emission factors were available for airplanes (kerosene, jet fuel etc.) and for vehicles fueled with LPG and CNG, therefore releases from these sources were not assessed.

The total PCDD/PCDF releases to air from the transport sector in 2004 were of 0.968 g TEQ. No emission to other media was accounted.

Baseline inventory (reference year: 2004)

5-Transport		Activity rate (t/year)	EFAir (µg TEQ/t)	Annual Release (g TEQ/year)
Source categories				Air	Water	Land	Product	Residue
a	4-Stroke engines	1,000,000
a1	Leaded fuel	80,000	2.2	0.176
a2	Unleaded fuel without catalyst	720,000	0.1	0.072
a3	Unleaded fuel with catalyst	100,000	0.00	0
b	2-Stroke engines	100,000		-
b1	Leaded fuel	20,000	3.5	0.07
bs	Unleaded fuel without catalyst	80,000	2.5	0.2
c	Diesel engines	500,000	0.1	0.05
d	Heavy oil fired engines	100,000	4	0.4
TOTAL for the source group				0.968

Starting with 2007, country X implements an action plan to reduce releases of unintentionally produced POPs, as part of its National Implementation Plan. Measures are taken to reduce releases from transport, in particular through phasing out leaded gasoline, upgrading of vehicle fleet (through implementation of stricter standards for vehicles, higher taxes for import of old cars, programs of old vehicle replacement etc.). In 2013, country X updates its inventory to assess the success of the measures implemented. Data are collected for the reference year 2010, and the inventory is established according to the Toolkit methodology as revised in 2013.

As a first step in the inventory updating process, the examination of the baseline inventory essential to show to the developer of the inventory where the information can be found, and which areas need extrapolation and expert judgment to fill gaps. The same approach is thus taken in the updated inventory as in the baseline, based on statistical data from the same sources, selective questionnaires sent to profile ministries, agencies and associations.

According to the new set of data, the total amount of fuel used for transport in 2010 was of 2’400’000 tons, registering a 50% increase since 2004. Leaded gasoline was phased out, and the share of fuel used for 2-stroke engines was reduced by 30%. A program on updating the car fleet was implemented; as a result, the share of 4-stroke vehicles with catalysts increased by 20%. Ethanol powered vehicles have replaced part of the gasoline powered vehicles; ethanol consumption is now estimated at 100’000 tons. This new information showed that 20% of vehicles still use inadequate catalyst or not at all, and were considered as not equipped with catalyst. Diesel fuel was partially replaced by biodiesel (35000 tons of biodiesel were used in 2010).

Available literature showed that ethanol powered vehicles have a lower emission factor than gasoline powered vehicles, and that biodiesel powered vehicles emit less PCDD/PCDF than diesel powered vehicles. Thus, the emission factor for ethanol vehicles equipped with catalyst is close to zero, and the emission factor for biodesel20 is 0.07 µg TEQ/t.

Results of the updated emission inventory (reference year: 2010) are shown below.

5-Transport		Activity rate (t/year)	EFAir (µg TEQ/t)	Annual Release (g TEQ/year)
Source categories				Air	Water	Land	Product	Residue
a	4-Stroke engines	1,500,000
	Leaded fuel	0	2.2	0
	Unleaded fuel without catalyst	1,080,000	0.1	0.108
	Unleaded fuel with catalyst	320,000	0.001	0.00032
	Ethanol with catalyst	100,000	0.0007	0.00007
b	2-Stroke engines	120,000
	Leaded fuel	0	3.5	0
	Unleaded fuel without catalyst	120,000	2.5	0.3
c	Diesel engines	700,000
	Regular Diesel	665,000	0.1	0.067
	Biodiesel	35,000	0.07	0.002
d	Heavy oil fired engines	100,000	2	0.2
TOTAL for the source group				0.677

The total dioxin and furan emissions were of 0.677 g TEQ in 2010.

The revision of the baseline inventory is necessary to ensure the consistency in trends in releases over time. In this example, the estimates for two source category pertaining to the transport group need to be revised.

With the updating of the inventory in 2013, country X discovers new information on the consumption of leaded gasoline by 4- and 2-stroke engines, which needs to be incorporated in the baseline inventory. The developer of the inventory needs to retrospectively assess the activity rate for this source and for the baseline year to enable the comparison of 2004 and 2010 release estimates. The volume of leaded fuel burned in 4- and 2-stroke engines in 2004 was thus reassessed.

The activity rates for leaded fuel the baseline year are re-estimated at 150000 t for 4-stroke and 50000 t for 2-stroke vehicles, and introducing the revised emission factors for gasoline and ethanol vehicles with catalyst and for heavy oil, the revised baseline release estimates are shown in the table below:

Revised baseline inventory (reference year: 2004)

5-Transport		Activity rate (t/year)	EFAir (µg TEQ/t)	Annual Release (g TEQ/year)
Source categories				Air	Water	Land	Product	Residue
a	4-Stroke engines	1,000,000
	Leaded fuel	80,000	2.2	0.33
	Unleaded fuel without catalyst	720,000	0.1	0.072
	Unleaded fuel with catalyst	100,000	0.001	0.0001
b	2-Stroke engines	100,000	-	-
	Leaded fuel	20,000	3.5	0.175
	Unleaded fuel without catalyst	80,000	2.5	0.2
c	Diesel engines	500,000	0.1	0.05
d	Heavy oil fired engines	100,000	2	0.2
TOTAL for the source group				1.027

The corresponding total dioxin and furan emission revised for the 2004 baseline year was of 1.027 g TEQ.

The results show a decrease of 34% in total releases from group 5 - Transport. If the new information was not incorporated to revise the baseline release estimate, the resulting trend would not have been the same, with an emission reduction of only 9%. The results of the inventory show that despite of the increase in motor fuel consumption in a country X, incentives to phase out leaded gasoline, switching to ethanol and upgrading of the vehicle fleet were important measures to reduce the overall PCDD/PCDF emissions from the transport sector.

This assessment was obtained through applying the same inventory approach and the same set of emission factors, therefore the results are readily comparable and the trends over time are consistent.