def dv_cont(T, P):
    """ Diffusivity of water vapor in air, neglecting non-continuum effects.

    See :func:`dv` for details.

    Parameters
    ----------
    T : float
        ambient temperature of air surrounding droplets, K
    P : float
        ambient pressure of surrounding air, Pa

    Returns
    -------
    float
        :math:`D_v(T, P)` in m^2/s

    See Also
    --------
    dv : includes correction for non-continuum effects

    """
    P_atm = P * 1.01325e-05
    return 0.0001 * (0.211 / P_atm) * (T / 273.0) ** 1.94
