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What's the difference between a Nebulizer and a Diffuser?

What is best for therapeutic benefit?

By Jennifer Stephens LRRT                                            


A Diffuser is any device which allows a liquid to evaporate thereby putting a scent into the surrounding environment. The process of diffusion is typically accomplished in 4 different ways:


(1) Heat---by applying heat, either through burning a candle, or by using an electrically heated vaporizer, the increased temperature will cause the essential oil to evaporate into the air.

(2) Ventilation---by utilizing a small fan to create airflow, evaporation is achieved when air passes over a wick or absorbent pad which holds the essential oil.

(3) Humidification---by using water and essential oil mixed together, a mist can be formed which will fill the air. This mist is produced either by a fan, heat or ultrasonic waves of energy.

(4) Nebulization---Is a process which forces the break down of essential oils into very tiny particles. It requires a high velocity, pressurized air stream and a specially designed jet nozzle. The rate of evaporation is highly accelerated and occurs almost instantly.

  • So, a diffuser is simply any device that imparts a scent into the air by evaporation.
  • A nebulizer is a specific type of diffuser that uses the process of nebulization to achieve evaporation.
  • A common misunderstanding is that Nebulizers and Diffusers are thought to be the same thing but they are not.
  • The diffusion method you choose, will determine to a large degree, the amount of aroma and therapeutic benefit you receive from an essential oil.

For example, if we use heat to evaporate the essential oil, it will gently produce a scent and fill the room nicely. However, heat has 2 drawbacks. First, it tends to alter the chemical composition of the essential oil which can destroy it’s purity and therapeutic value. Second, while heat does produce a nice aroma, it may not be therapeutically useful. The size and availability of breathable molecules are mostly filtered out by the nose hairs and nasal cavity. (see EGAN for more in-depth details)

Ventilation offers an economical and simple way to provide evaporation. Since there is no heat involved, the chemical composition of the essential oil remains intact. But again, the size and availability of breathable molecules compromises therapeutic benefits. Ventilation is a good way to scent a room as long as it’s not too large.

Humidification has many health benefits, but is the least effective way to provide aroma because the majority of the mist is water vapor. Using a humidifier may produce a nice scent, but has very limited healing capacity since the amount of essential oil is so small.

Nebulization is absolutely the best way to provide both aroma and therapeutic healing value with essential oils. It does not alter the chemical composition of the oils. It breaks down pure essential oil molecules without separation of the mixture. It produces a particle size small enough for the lungs and body to absorb them rapidly.

Its only drawback is expense—it costs more to create a steady pressurized air flow than to create heat or rotate a fan. However, no method of diffusing is as effective in preserving the natural healing qualities of essential oils.

Breaking down the oil in its natural state maintains purity and provides the most effective bioavailable therapy to the cells of the human body. Nebulization is the only method of diffusion that creates particles small enough to reach the deep part of the lungs.

A particles depth of penetration into the respiratory tract varies inversely with its size.

Particles between 5 and 20 microns will only reach the upper airway: nose, larynx, trachea.

Particles between 2 and 5 microns will reach the lower airways.

Particles between 1 and 3 microns will reach the alveolar region: (deep part of the lung)

(see reference to EGAN for more details)

In conclusion, if all you want to do is provide a pleasant scent to your environment, any diffuser will work fine. But if you want to use essential oils for their maximum healing qualities and pure therapeutic benefit, only a nebulizer will do the job correctly and effectively.

This is why doctors and respiratory professionals prescribe the use of a nebulizer to administer inhalants of a medicinal or therapeutic nature.

Jennifer Stephens LRRT      (Licensed and Registered Respiratory Therapist)

References:  EGAN’s Fundamentals of Respiratory Care-- Seventh edition--copyright 1999 by Mosby, INC. Page 158 (Nasal Cavity) and pages 684-685 (Particle Size)




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