When you enter malls or stores in mall settings, you will probably inhale a smoky perfume incense very popular in Saudi known as Oud. What is Oud you ask and why do people burn it? I found some information online that describes it best. It sells for a few hundred SAR to 5,000 SAR or more. If you want to read the study for effects on lung health please click link below.
“In most of the Arab countries, incense burning, including Oud, is widely used by many people. Many substances are used to produce incense including Oud, frankincense, aromatic wood, herbs, flowers, essential oils, and perfumes. The most commonly used incense for burning in Saudi Arabia is Oud. The Oud tree is known as the Aquilaria agallocha, which has at least 15 species of Aquilaria and is also known as lignum aloe, agarwood, and eagle wood. The unique aroma, which is produced as a result of fungal infection to the heartwood tree, has been used since ancient times as a source of perfumes and incense in the Middle East. The perfumes of the agarwood known as Oud are common in Saudi Arabia and the United Arab Emirates. They are not only inhaled but also used in making perfumes in many other countries. Although Oud is the most popular incense burned, it is also mixed with various other natural scents. All of these including the Oud are mostly burned in traditional charcoal burners.”
“Arabian Oud is a natural indoor fragrance, especially in occasions like wedding parties and other ceremonies. It is also used to perfume clothing and home. Because of its wide use, many individuals are exposed to its fumes throughout large parts of the day in Eastern countries and, especially in Saudi Arabia. The produced incense from burning Oud in a humid and poorly ventilated indoor environment tends to persist over long periods.”published in Annals of Saudi Medicine 2015 Mar-Apr; 35(2): 111–119, on National Institute of Health website