2.2. Implementation of different sampling strategies
The long-term online dataset that came forth from this
monitoring campaign was subjected to different sampling
strategies based on the ones that have been used in the previous
studies mentioned in Table 1. The evaluated sampling
strategies are presented in Table 2.
2.2.1. 24 h online sampling
A 24 h online sampling strategy was applied by Ahn et al.
(2010b). The exact sampling frequency is not mentioned.
Presumably, such a monitoring campaign would last e.g. from
11 a.m. on a working day until 11 a.m. the next working day.
The average over this 24 h period would yield an estimated
daily emission flow rate (kg N2OeN d1
). This strategy was
applied to every 24 h period of the present online long-term
dataset, starting at 11 a.m. on a Monday, a Tuesday, a
Wednesday or a Thursday (it was presumed that a WWTP