Is it possible to operate the MOUSE-E-MOTION Universal Data Logger in humid or dusty surroundings our outdoors?

Yes, if the data logger is protected against intrusion of moisture or dust particles using thin polyethylene film or comparable wrapping material. This has normally only very little influence on the detection capability of the motion sensor. The impact on the light sensor depends on the transparency of the applied wrapper. The effect on temperature measurement also depends on the properties of the wrapping material because of passing on the temperature from the environment to the sensor is more or less impeded or at least slowed down. And of course, measuring the relative humidity of the surroundings is impossible in this case because the humidity sensor is completely isolated from the ambient conditions. It is advisable to perform a small series of tests to check the ability to correctly detect the desired parameters before using a wrapped logger.