emi_europe_emep_wear {gtfs2emis}R Documentation

Emissions from road vehicle tyre, brake, and surface wear from the European Environment Agency (EMEP/EEA) model

Description

Returns a list or data.table of emissions for urban buses based on Tier 2 of EMEP/EEA air pollutant emission inventory guidebooks (2019). The function concerns the emissions of particulate matter (PM), encompassing black carbon (BC) (1), which arises from distinct sources, namely, road vehicle tire and brake wear (NFR code 1.A.3.b.vi), and road surface wear (NFR code 1.A.3.b.vii). It is important to note that PM emissions exhaust from vehicle exhaust are excluded. The focus is on primary particles, which refer to those that are directly emitted due to surface wear, rather than those generated from the resuspension of previously deposited material. See more in @details.

Usage

emi_europe_emep_wear(
  dist,
  speed,
  pollutant,
  veh_type,
  fleet_composition,
  load = 0.5,
  process = "tyre",
  as_list = TRUE
)

Arguments

dist

units; Length of each link in 'km'.

speed

units; Speed in 'km/h'.

pollutant

character; Pollutant, classified in "TSP"(Total Suspended Particles), "PM10","PM2.5", "PM1.0","PM0.1". Please note that emissions factors for "PM1.0" and "PM0.1" are not available for road surface wear process.

veh_type

character; Bus type, classified in "Ubus Midi <=15 t", "Ubus Std 15 - 18 t", "Ubus Artic >18 t", "Coaches Std >18 t", or "Coaches Artic >18 t".

fleet_composition

vector; Fleet composition, which is a distribution of fleet based on frequency. If there is only one, 'fleet_composition' is 1.0.

load

numeric; Load ratio, classified in 0.0, 0.5 and 1.0. Default is 0.5.

process

character; Emission process sources, classified in "tyre","brake" and/or "road".

as_list

logical; Returns emission factors as a list, instead of data.table format. Default is TRUE.

Details

The following equation is employed to evaluate emissions originating from tyre and brake wear

TE(i) = dist x EF_tsp(j) x mf_s(i) x sc(speed),

where:

Tyre

In the case of heavy-duty vehicles, the emission factor needs the incorporation of vehicle size, as determined by the number of axles, and load. These parameters are introduced into the equation as follows:

EF_tsp_tyre_hdv = 0.5 x N_axle x LCF_tyre x EF_tsp_tyre_pc

where

and LCF_tyre = 1.41 + (1.38 x LF),

where:

The function considers the following look-up table for number of vehicle axes:

vehicle class (j) number of axes
Ubus Midi <=15 t 2
Ubus Std 15 - 18 t 2
Ubus Artic >18 t 3
Coaches Std <=18 t 2
Coaches Artic >18 t 3

The size distribution of tyre wear particles are given by:

particle size class (i) mass fraction of TSP
TSP 1.000
PM10 0.600
PM2.5 0.420
PM1.0 0.060
PM0.1 0.048

Finally, the speed correction is:

sc_tyre(speed) = 1.39, when V < 40 km/h; sc_tyre(speed) = -0.00974 x speed + 1.78, when 40 <= speed <= 90 km/h; sc_tyre(speed) = 0.902, when speed > 90 km/h.

Brake

The heavy-duty vehicle emission factor is derived by modifying the passenger car emission factor to conform to experimental data obtained from heavy-duty vehicles.

EF_tsp_brake_hdv = 1.956 x LCF_brake x EF_tsp_brake_pc

where:

and LCF_brake = 1 + (0.79 x LF),

where:

The size distribution of brake wear particles are given by:

particle size class (i) mass fraction of TSP
TSP 1.000
PM10 0.980
PM2.5 0.390
PM1.0 0.100
PM0.1 0.080

Finally, the speed correction is:

sc_brake(speed) = 1.67, when V < 40 km/h; sc_brake(speed) = -0.0270 x speed + 2.75, when 40 <= speed <= 95 km/h; sc_brake(speed) = 0.185, when speed > 95 km/h.

Road Wear

Emissions are calculated according to the equation:

TE(i) = dist x EF_tsp_road(j) x mf_road

where:

The following table shows the size distribution of road surface wear particles

particle size class (i) mass fraction of TSP
TSP 1.00
PM10 0.50
PM2.5 0.27

References

#' EMEP/EEA data and reports can be accessed in the following links:

Value

List. emission in units 'g' (list or a data.table).

See Also

Other Emission factor model: ef_brazil_cetesb(), ef_europe_emep(), ef_scaled_euro(), ef_usa_emfac(), ef_usa_moves()

Examples

emi_europe_emep_wear(dist = units::set_units(1,"km"),
                     speed =  units::set_units(30,"km/h"),
                     pollutant = c("PM10","TSP","PM2.5"),
                     veh_type = c("Ubus Std 15 - 18 t","Ubus Artic >18 t"),
                     fleet_composition = c(0.5,0.5),
                     load = 0.5,
                     process = c("brake","tyre","road"),
                     as_list = TRUE)

[Package gtfs2emis version 0.1.1 Index]