Mass budget simulation of NOx and CO for the evaluation of calculated emissions for the city of Augsburg (Germany)

Determining air pollutant emission rates based on mass balance using airborne measurement data over the Alberta oil sands operations

“…A mass-balance approach is then employed to derive the emission rate within the enclosed volume by calculating the total advective fluxes of the emitted material though the surrounding screen. A model comparison (Panitz et al, 2002) of the Kathoff et al (2002) study concluded that the advective fluxes account for between 85 and 95 % of the total emissions, suggesting a much lower uncertainty compared to the single-heighttransect or single-screen methods described above.…”

“…In the last case, the box can refer to a cylinder, CO Peischl et al (2013) Single-height transect CO 2 , CH 4 , CO Karion et al (2013) Single-height transect CH 4 Wratt et al (2001) Up and downwind spirals CH 4 Gatti et al (2014) Up and downwind spirals CO, CO 2 Mays et al (2009) Single screen CO 2 , CH 4 Cambaliza et al (2014) Single screen CO 2 , CH 4 Walter et al (2012) Single screen (DOAS) SO 2 Kalthoff et al (2002) Box CO, NO x Alfieri et al (2010) Box CO 2 a rectangular cuboid, or any other prism shape that is uniform with height. The simplest flight pattern, which we refer to as a singleheight transect, is a single flight path at one height perpendicular to the mean wind direction and downwind of the point or area sources (Turnbull et al, 2009;Peischl et al, 2013;Karion et al, 2013). This approach assumes a wellmixed boundary layer, such that the species mixing ratio is constant and equal to the measured value between the surface and the boundary-layer height.…”

“…This approach assumes a wellmixed boundary layer, such that the species mixing ratio is constant and equal to the measured value between the surface and the boundary-layer height. Upwind of the source, the species mixing ratio is assumed to be equal to a constant background value determined either from the outside edges of the downwind transect (Turnbull et al, 2009) or from a second, upwind transect (Peischl et al, 2013;Karion et al, 2013). Author-derived uncertainties in the calculated emission rate based on this approach are estimated as ±50 % (Peischl et al, 2013;Karion et al, 2013).…”

“…Upwind of the source, the species mixing ratio is assumed to be equal to a constant background value determined either from the outside edges of the downwind transect (Turnbull et al, 2009) or from a second, upwind transect (Peischl et al, 2013;Karion et al, 2013). Author-derived uncertainties in the calculated emission rate based on this approach are estimated as ±50 % (Peischl et al, 2013;Karion et al, 2013). In comparing method uncertainties it is noted that different authors use inconsistent methodologies to estimate total uncertainties, and some estimates are more conservative than others.…”

Errors in model predictions of NOxtraffic emissions at road level – impacts of input data quality

“…In the US and Europe, a number of studies have compared ambient air sampling data or emission fluxes to the results from combined emission and dispersion modeling [1][2][3][4]. For NO x , differences varying between a factor (predicted/observed) of 1.0 [1] to 2.2 [4] have been found.…”