def humid_ratio_from_db_rh(db_temp, rel_humid, b_press=<NUM_LIT>):
<EOL>p_ws = saturated_vapor_pressure(db_temp + <NUM_LIT>)<EOL>decrh = rel_humid * <NUM_LIT><EOL>p_w = decrh * p_ws<EOL>press_differ = b_press - p_w<EOL>constant = p_w * <NUM_LIT><EOL>humidity_ratio = constant / press_differ<EOL>return humidity_ratio<EOL>
Humidity Ratio (kg water/kg air) at a db_temp (C),
    rel_humid (%) and Pressure b_press (Pa).

    Note:
        [1] Vaisala. (2013) Humidity Conversion Formulas:
        Calculation Formulas for Humidity.
        www.vaisala.com/Vaisala%20Documents/Application%20notes/Humidity_Conversion_Formulas_B210973EN-F.pdf