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Implemented Humidity + Temperature half life function from Dabish et al.

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jdevine 2022-04-21 13:42:55 +02:00
parent 987454928c
commit 5b715937d2
1 changed files with 9 additions and 9 deletions
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18
cara/models.py
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@ -439,28 +439,28 @@ class Virus:
#: Pre-populated examples of Viruses.
types: typing.ClassVar[typing.Dict[str, "Virus"]]
def halflife(self, humidity: _VectorisedFloat) -> _VectorisedFloat:
def halflife(self, humidity: _VectorisedFloat, inside_temp: _VectorisedFloat) -> _VectorisedFloat:
# Biological decay (inactivation of the virus in air) - virus
# dependent and function of humidity
raise NotImplementedError
def decay_constant(self, humidity: _VectorisedFloat) -> _VectorisedFloat:
def decay_constant(self, humidity: _VectorisedFloat, inside_temp: _VectorisedFloat) -> _VectorisedFloat:
# Viral inactivation per hour (h^-1) (function of humidity)
return np.log(2) / self.halflife(humidity)
return np.log(2) / self.halflife(humidity, inside_temp)
@dataclass(frozen=True)
class SARSCoV2(Virus):
def halflife(self, humidity: _VectorisedFloat) -> _VectorisedFloat:
def halflife(self, humidity: _VectorisedFloat, inside_temp: _VectorisedFloat) -> _VectorisedFloat:
"""
Half-life changes with humidity level. Here is implemented a simple
piecewise constant model (for more details see A. Henriques et al,
CERN-OPEN-2021-004, DOI: 10.17181/CERN.1GDQ.5Y75)
"""
# Taken from Morris et al (https://doi.org/10.7554/eLife.65902) data at T = 22°C and RH = 40 %,
# and from Doremalen et al (https://www.nejm.org/doi/10.1056/NEJMc2004973).
return np.piecewise(humidity, [humidity <= 0.4, humidity > 0.4], [6.43, 1.1])
# Updated to use the formula from Dabish et al. https://doi.org/10.1080/02786826.2020.1829536
# with a minimum at hl = 1.1
return max(1.1, (0.693/(0.16030 + 0.04018((inside_temp-20.615)/10.585)+0.2176((humidity-45.235)/28.665)+0.1)))
Virus.types = {
@ -917,9 +917,9 @@ class ConcentrationModel:
h = 1.5
# Deposition rate (h^-1)
k = (vg * 3600) / h
#todo: Inside_temp needs to be exposed/added to the room;
return (
k + self.virus.decay_constant(self.room.humidity)
k + self.virus.decay_constant(self.room.humidity, self.room.inside_temp)
+ self.ventilation.air_exchange(self.room, time)
)