A stream of air vapourises the essential oils keeping the fragrance pure until the oil is spent. This avoids heating the oil, which may burn it, altering the fragrance and changing its properties. Because the diffuser doesn’t use heat, it is safe to leave running for several hours, or whilst someone sleeps. This can be particularly useful with conventional cough and cold vapour remedies and for use in a child’s bedroom. Using natural oil means no artificial chemicals and it is kind to your environment.