Incense sticks have been used for thousands of years all around the world. They have been used extensively especially in Asian countries where Buddhism and Taoism are practiced daily.
(The following paragraph is from the NCBI website)
Incense smoke (fumes) contains particulate matter (PM), gas products and many organic compounds. On average, incense burning produces particulates greater than 45 mg/g burned as compared to 10 mg/g burned for cigarettes. The gas products from burning incense include CO, CO2, NO2, SO2, amongst others. Incense burning also produces volatile organic compounds, such as benzene, toluene, and xylenes, as well as aldehydes and polycyclic aromatic hydrocarbons (PAHs).
Incense sticks and the delightful fragrances they produce deliver a beautiful sense of calm and serenity to and area where they are burned. Or depending on the blend and ingredients they can also be uplifting and used to energise.
To use you just light the end of the incense stick and blow out the flame. Make sure to place in a suitable holder.