Gas emission was estimated according
toeq 1 , where E is the emission rate (g h–1), M is the molar mass (g mol–1), Cout is the concentration (atm) measured in the
air outlet from the sections, Cin is the
concentration (atm) measured in the air inlet for the sections, Q is the ventilation rate (m3 h–1), R is the gas constant (m3·atm·K–1·mol–1), and T is the temperature (K).
Odor was assessed as
the odorant concentration and estimated as the sum of odor activity
values (SOAV) for hydrogen sulfide and the eight VOCs according toeq 2 in which SOAV is calculated
as the concentration measured by PTR-MS divided by the odor threshold
value (OTV, units of ppbv) for each of the nine odorants.
Odor
emission was estimated according toeq 3 , where Eodor is
the emission (SOAV s–1), SOAV is the sum of odor
activity values expressed per m3 (SOAV m–3), and Q is the ventilation rate (m3 h–1).
Enteric
methane emission was calculated on a daily basis according
toeq 4 ,10 where ECH4 enteric (g
pig–1 d–1) is the enteric methane
emission, GE is the gross energy consumption (MJ d–1 pig–1), Ym is the
fraction of gross energy intake being converted to methane (%), n is the number of pigs in the section, and 0.005565 is
the energy content of methane (MJ g–1).
Ym was set to 0.24% based on an average
of four studies.19 (link)−22 (link) Slurry methane emission was estimated by subtracting enteric methane
emission fromeq 4 from
the measured total methane emission.
Enteric carbon dioxide
emission, ECO2 enteric (g pig–1 d–1), was calculated
using the empirical relationship ineq 5 ,23 (link) where BW is the pig
body weight (kg). The constants ineq 5 were derived from fitting to multiple datasets.23 (link)
The average daily body
weight of pigs was calculated by linear
interpolation between in and outgoing weights of the pigs. Linear
growth is a realistic assumption for pigs that are between 100 and
200 days old (as in this study).24 (link)
to
air outlet from the sections, Cin is the
concentration (atm) measured in the air inlet for the sections, Q is the ventilation rate (m3 h–1), R is the gas constant (m3·atm·K–1·mol–1), and T is the temperature (K).
Odor was assessed as
the odorant concentration and estimated as the sum of odor activity
values (SOAV) for hydrogen sulfide and the eight VOCs according to
as the concentration measured by PTR-MS divided by the odor threshold
value (OTV, units of ppbv) for each of the nine odorants.
Odor
emission was estimated according to
the emission (SOAV s–1), SOAV is the sum of odor
activity values expressed per m3 (SOAV m–3), and Q is the ventilation rate (m3 h–1).
Enteric
methane emission was calculated on a daily basis according
to
pig–1 d–1) is the enteric methane
emission, GE is the gross energy consumption (MJ d–1 pig–1), Ym is the
fraction of gross energy intake being converted to methane (%), n is the number of pigs in the section, and 0.005565 is
the energy content of methane (MJ g–1).
Ym was set to 0.24% based on an average
of four studies.19 (link)−22 (link) Slurry methane emission was estimated by subtracting enteric methane
emission from
the measured total methane emission.
Enteric carbon dioxide
emission, ECO2 enteric (g pig–1 d–1), was calculated
using the empirical relationship in
body weight (kg). The constants in
The average daily body
weight of pigs was calculated by linear
interpolation between in and outgoing weights of the pigs. Linear
growth is a realistic assumption for pigs that are between 100 and
200 days old (as in this study).24 (link)
