Report - DCE - Nationalt Center for Miljø og Energi

The normative figures (Poulsen et al. 2001, Poulsen, 2011) are comprised of
arithmetic means. Based on feeding plans, the standard deviation in Nexcretion
rates between farms can be estimated to ±20 % for all animal types
(Hanne D. Poulsen, pers. comm). However, due to the large number of
farms included in the norm figures the arithmetic mean, it can be assumed
as a very good estimate with a low uncertainty.
The combined effect of low uncertainty in actual animal numbers, the relatively
low uncertainty for feed consumption and excretion rates gives a low
uncertainty in the activity data as a whole and is estimated to 10 %. The major
uncertainty, therefore, relates to the emission factors.
% B 4ZOUIFUJD / GFSUJMJ[FST
The activity data for the emission from synthetic fertiliser is the amount of
sold fertiliser given by the Danish Plant Directorate. Uncertainty for this is
considered to be low. The uncertainty for the emission factors is based on
expert judgement.
% D / FYDSFUJPO PO QBTUVSF SBOHF BOE QBEEPDL
The number of days and the N-excretion on grass is estimated by DAAS and
DCA, Aarhus University. The overall uncertainty for the activity is estimated
to 5 %, while the uncertainty for the emission factor is considered
higher, 25 %.
( 0UIFS
Under Table 4G emissions from three sources are reported, crops, sewage
sludge and NH3 treated straw. The uncertainty of activity data for crops is
very low, while it for sewage sludge and NH3 treated straw is higher. For
the uncertainty of the emission factor for the three sources a high uncertainty
is seen for crops and NH3 treated straw, while it for sewage sludge is
lower. For both activity and emission factor an overall uncertainty is estimated.
1
Previously the uncertainties for the PM emission factors have been considered
to be very high and especially for manure management. The uncertainty
estimates regarding the PM emission factors for is based on
EMEP/EEA guidebook.
0UIFS QPMMVUBOUT
For the NMVOC emission from 4G Other the activity data is hectares of arable
crops and grassland. Data for hectares under cultivation is estimated by
Statistic Denmark and the uncertainties are based on the calculations and
they are very low. The uncertainty for the emission factors is based on expert
judgment and is consider being very high. For the NMVOC emission from
field burning the uncertainty of the emission factor is based on EMEP/EEA
guidebook.
Emission of NOx, CO, SO2, heavy metals, dioxin and PAH from the agricultural
sector originates from field burning of agricultural wastes. The uncertainty
for activity data for these emissions is a combination of the uncertainty
for crop production which is low and the uncertainty of the amount of
burned straw which is high. The uncertainties for the emission factors are