Inhalation by diffusion is one of the safest and most effective ways to reap the benefits of essential oils. In fact, it’s the fastest way to get essential oils into your bloodstream! However, there is some confusion about how to do it safely and effectively. Here is a primer on how to choose the right oils and diffuser for your needs. While ultrasonic diffusers are worth the investment if you’re interested in adding scent to your home or workspace, they also come with some drawbacks. For instance, they need water to operate, which can prove inconvenient at times, and they require occasional cleaning. The largest qualm about ultrasonic diffusers is that the aromatic scent molecules are diluted with water, which means that top notes, like citrus oils, are extremely volatile and faint in smell. To get a stronger smell, you will need to add more drops of lighter notes, like lemon, orange, and grapefruit. Or you can replenish those top notes more frequently than you would have to with some other aromatic devices, like a nebulizer. While nebulizing is my go-to for dealing with acute sickness, ultrasonic diffusing is often the most economical choice for daily use. Nebulizers can be a bit more costly than other diffusing devices and are easily breakable. And because you are not diluting the oils with water like you do when ultrasonic diffusing, nebulizing can use up your oils in a flash. Another downside is that viscous oils, like vetiver, patchouli, and sandalwood won’t really atomize, which will leave you with a vial in need of a deep cleaning. To clean, just rinse the glass with rubbing alcohol. Nowadays, most diffusers come with a timer setting to help you customize your preferences. But keep in mind there are a number of factors that affect how well diffusion works. First, each essential oil will stay in the air for a different amount of time. Top notes, like peppermint, lavender, and eucalyptus typically evaporate within an hour or two. Middle notes, like rosemary, geranium, and chamomile, often aromatically evaporate within two to four hours. And heavier base notes, like myrrh, cedarwood, and ginger can be detected by olfaction for five or more hours and may even linger for days. Creating balanced synergies can help make a scent last longer or enhance overall therapeutic benefit. For example, combining top notes with complementary base notes helps stabilize the more volatile top note chemicals, making them detectable longer than diffusing just that single note. The environment also affects diffusion. Room temperature and air circulation can cause molecules to evaporate more or less quickly. For example, warm spaces create greater excitement within bonds of aromatic molecules, which causes them to vanish rapidly. So you may need to add a few extra drops if you’re diffusing in a particularly hot room. Also be wary that any overpowering HVAC system may accelerate spreading the molecules throughout a space. The opposite can also be true; rapid air movement may cause the scent to last for less time. While inhalation and diffusing are wonderful and easy ways to integrate essential oils into your routine, keep in mind that you should always diffuse in a well-ventilated area and make sure that what you’re diffusing is safe for pets, children, or anyone else who may be around.