To reduce the particulate loading indoors to be in compliance with the NAAQS, an ACH of >6 is preferred in the same room with V (40 m3). Alternatively, if incense burning takes place in a larger room with a volume of 100 m3, an ACH of 3 would be sufficient regardless of incense
brands. If incense burning is inevitable, people should choose smokeless incense sticks, or those with shorter burning duration to minimize exposure to incense smoke; whenever possible, they should try not to be in the same room as the altar. It should be noted that this health threat can be multiplied many times for worshippers in temples as they may be continuously breathing in incense smoke particles from thousands of incense sticks burned by devotees for 8-10 h in a day.