Package 'humidity'

calculate absolute humidity

Description

calculate absolute humidity $\rho_w$ based on partial water vapor pressure $e$ at temperature $t$

Usage

AH(e, t, isK = TRUE)

Arguments

e	partial water vapor pressure in Pascal (Pa)
t	temperature in Kelvin (K) or in degree Celsius (°C)
isK	logical indicator whether temperature is in Kelvin (K). The default value is TRUE.

Value

numeric absolute humidity $\rho_w$ ($kg/m^3$)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

WVP1, WVP2, RH, SH.

Examples

t <- 273.15
Es <- SVP(t)
e <- WVP2(70, Es)
AH(e, t)

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Celsius to Kelvin conversion

Description

convert temperature in degree Celsius (°C) into Kelvin (K)

Usage

C2K(C)

Arguments

C	temperature in degree Celsius (°C)

Value

numeric temperature in Kelvin (K)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

K2C.

Examples

T0 # zero degrees Celsius in Kelvin (K)
C2K(T0)

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Saturation vapor pressure (hPa) at 0 degrees Celsius

Description

$e_s(T_0) = 6.11hPa$ is the saturation vapor pressure at 0 degrees Celsius ($T_0 = 273.15K$).

Usage

Es.T0

See Also

T0

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Viability of influenza A virus for 1 hour after spraying

Description

A dataset containing airborne virus particles of influenza A for viable survival in the dark at controlled temperature and relative humidity for 1 hour after spraying.

Usage

ivs

Format

A data frame with 11 rows and 3 variables:

• T: temperature in degree Celsius (7.5–32.0)

• RH: relative humidity in percentage (20–82)

• PV: percentage of viable virus (6.6–78.0)

Source

Harper, G. J. (1961). Airborne micro-organisms: survival tests with four viruses. Journal of Hygiene, 59(04), 479-486.

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Aerosol transmission efficiency of influenza A virus from guinea pigs to guinea pigs

Description

A dataset containing aerosol transmission efficiency of influenza A virus from four infected guinea pigs to four exposed guinea pigs under conditions of controlled temperature and relative humidity.

Usage

ivt

Format

A data frame with 24 rows and 4 variables:

• T: temperature in degree Celsius (5–30)

• RH: relative humidity in percentage (20–80)

• PT: transmission efficiency in percentage (0–100)

• source: data source

Source

Lowen, A. C., Mubareka, S., Steel, J., & Palese, P. (2007). Influenza virus transmission is dependent on relative humidity and temperature. PLoS pathogens, 3(10), e151.

Lowen, A. C., Steel, J., Mubareka, S., & Palese, P. (2008). High temperature (30℃) blocks aerosol but not contact transmission of influenza virus. Journal of virology, 82(11), 5650-5652.

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Kelvin to Celsius conversion

Description

convert temperature in Kelvin (K) into degree Celsius (°C)

Usage

K2C(K)

Arguments

K	temperature in Kelvin (K)

Value

numeric temperature in degree Celsius (°C)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

C2K.

Examples

K2C(0)

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Latent heat of water vapor

Description

Latent heat of water vapor $L = 2.5 \times 10^6J/kg$

Usage

L

---

Molecular weight of dry air

Description

Molecular weight of dry air $M_d = 28.9634g/mol$

Usage

Md

See Also

Mw

---

calculate mixing ratio

Description

calculate mixing ratio $\omega$ based on specific humidity $q$

Usage

MR(q)

Arguments

q	specific humidity $q$ ($kg/kg$)

Value

numeric mixing ratio $\omega$ ($kg/kg$)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

SH.

Examples

t <- 273.15
Es <- SVP(t)
e <- WVP2(70, Es)
q <- SH(e, p = 101325)
MR(q)

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Molecular weight of water vapor

Description

Molecular weight of water vapor $M_w = 18.01528g/mol$

Usage

Mw

See Also

Md

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calculate relative humidity

Description

calculate relative humidity $\psi$ based on temperature $t$ and dew point $T_d$

Usage

RH(t, Td, isK = TRUE)

Arguments

t	temperature in Kelvin (K) or in degree Celsius (°C)
Td	dew point in Kelvin (K) or in degree Celsius (°C)
isK	logical indicator whether temperature is in Kelvin (K). The default value is TRUE.

Value

numeric relative humidity in %.

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

AH, SH.

Examples

RH(30, 15, isK = FALSE)

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Specific gas constant of water vapor

Description

Specific gas constant of water vapor $R_w = \frac{1000R}{M_w} = 461.52J/(kgK)$, where $R = 8.3144621J/(molK)$ is the molar gas constant and $M_w = 18.01528g/mol$ is the molecular weight of water vapor.

Usage

Rw

See Also

Mw

---

calculate specific humidity

Description

calculate specific humidity $q$ based on partial water vapor pressure $e$ under given atmospheric pressure $p$

Usage

SH(e, p = 101325)

Arguments

e	partial water vapor pressure in Pascal (Pa)
p	atmospheric pressure in Pascal (Pa). The default is standard atmospheric pressure of 101325Pa.

Value

numeric specific humidity $q$ ($kg/kg$)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

WVP2, WVP2, AH, RH, MR.

Examples

t <- 273.15
Es <- SVP(t)
e <- WVP2(70, Es)
SH(e, p = 101325)

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convert specific humidity into relative humidity

Description

Climate models usually provide specific humidity only; however, relative humidity is used to compute heat index that is really useful for health impacts studies. This function converts specific humidity $q$ into relative humidity $\psi$ at temperature $t$ and under atmospheric pressure $q$.

Usage

SH2RH(q, t, p = 101325, isK = TRUE)

Arguments

q	specific humidity $q$ ($kg/kg$)
t	temperature in Kelvin (K) or in degree Celsius (°C)
p	atmospheric pressure in Pascal (Pa). The default is standard atmospheric pressure of 101325Pa.
isK	logical indicator whether temperature is in Kelvin (K). The default value is TRUE.

Value

numeric relative humidity in %.

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

AH, SH.

Examples

SH2RH(0.005867353, 22.25, p = 101325, isK = FALSE)

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calculate saturation vapor pressure

Description

calculate saturation vapor pressure $E_s$ at temperature $t$, using the Clausius-Clapeyron equation or the Murray equation.

Usage

SVP(t, isK = TRUE, formula = c("Clausius-Clapeyron", "Murray"))

Arguments

t	temperature in Kelvin (K) or in degree Celsius (°C)
isK	logical indicator whether temperature is in Kelvin (K). The default value is TRUE.
formula	the formula is used for calculating saturation vapor pressure. By default the Clausius-Clapeyron equation is used.

Value

numeric saturation vapor pressure in hectopascal (hPa) or millibar (mb)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

SVP.ClaCla, SVP.Murray.

Examples

SVP(273.15)

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calculate saturation vapor pressure using the Clausius-Clapeyron equation

Description

calculate saturation vapor pressure $E_s$ at temperature $t$, using the Clausius-Clapeyron equation.

Usage

SVP.ClaCla(t)

Arguments

t	temperature in Kelvin (K)

Value

numeric saturation vapor pressure in hectopascal (hPa) or millibar (mb)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

References

Shaman, J., & Kohn, M. (2009). Absolute humidity modulates influenza survival, transmission, and seasonality. Proceedings of the National Academy of Sciences, 106(9), 3243-3248.

Wallace, J. M., & Hobbs, P. V. (2006). Atmospheric science: an introductory survey (Vol. 92). Academic press.

See Also

SVP.Murray, SVP.

Examples

T0 # zero degrees Celsius in Kelvin (K)
SVP.ClaCla(T0)

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calculate saturation vapor pressure using the Murray equation

Description

calculate saturation vapor pressure $E_s$ at temperature $t$, per the equation proposed by Murray (1967).

Usage

SVP.Murray(t)

Arguments

t	temperature in Kelvin (K)

Value

numeric saturation vapor pressure in hectopascal (hPa) or millibar (mb)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

References

Murray, F. W. (1967). On the Computation of Saturation Vapor Pressure. Journal of Applied Meteorology, 6(1), 203-204.

See Also

SVP.ClaCla, SVP.

Examples

T0 # zero degrees Celsius in Kelvin (K)
SVP.Murray(T0)

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Zero degrees Celsius in Kelvin

Description

Temperature corresponding to 0 degrees Celsius on the Kelvin scale.

Usage

T0

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calculate partial water vapor pressure given dew point

Description

calculate partial water vapor pressure $e$ based on dew point $T_d$

Usage

WVP1(Td, isK = TRUE)

Arguments

Td	dew point in Kelvin (K) or in degree Celsius (°C)
isK	logical indicator whether temperature is in Kelvin (K). The default value is TRUE.

Value

numeric partial vapor pressure in hectopascal (hPa) or millibar (mb)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

SVP, SVP.ClaCla.

Examples

T0 # zero degrees Celsius in Kelvin (K)
WVP1(T0)

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calculate partial water vapor pressure given relative humidity and saturation water vapor pressure

Description

calculate partial water vapor pressure $e$ based on relative humdity $\psi$ and saturation water vapor pressure at temperature $t$

Usage

WVP2(psi, Es)

Arguments

psi	relative humidity $\psi$ in percentage ($\%$)
Es	saturation vapor pressure $e_s$(hPa) at temperature $t$, which can be calculated by callling SVP function.

Value

numeric partial water vapor pressure in Pascal (Pa)

Author(s)

Jun Cai ([email protected]), Young Research Fellow at the School of Public Health, Fudan University

See Also

SVP, SVP.ClaCla, SVP.Murray.

Examples

Es <- SVP(273.15)
WVP2(70, Es)

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