Burning incense can seem safe but did you know incense smoke can actually have negative effects on your heath that are similar to second hand smoke? Inhalation of incense smoke can over time cause health problems which can be potentially serious. Studies have shown that long term exposure to incense smoke in your home can put you at an increased risk of heart disease and cardiovascular related deaths. Also a lot of incense are treated with chemicals and other harmful ingredients.
Different types of incense can have different effects since not all incense is made the same. If you do decide to burn or keep burning incense always make sure you have proper ventilation like having the incense close to a window. Never burn too much incense in a smaller room. Certain guidelines can help minimize the risk but all in all it is still probably not a good idea to keep burning incense over a long period of time.