For human comfort and convenience, appropriate temperature values may not be sufficient enough for the environment that they live in. The moisture content of the air has an important place in this regard. 30% to 65% humidity is desireable for a relaxed and comfortable life. Humidity in the environment is fundamental for the human health, convenience and comfort. Humidity is also valid for therapeutics. The drugs that are used in medicine for diagnosis and therapy must be inhaled with cold or hot water vapor in case drug effectiveness is desired to be increased. For such achievments, cold vaporization method is being preferred to reach the alveoli of the patients, thus, the drug can be used in a more efficient manner without damaging the respiratory tract. In this project, effect of ambient temperaure in ultrasonic nebulizers is investigated. It is proved that as the temperature increases 5°C, the speed of cold vapor increases 10% which refers a decrease in particle diameter. The variations in particle dimension may severely effect the efficiency of therapeutics. Therefore, in this study, it is presented that ultrasonic nebulizers should be designed considering ambient temperature. A design rationale is proposed in this study.