DUBAI // Burning traditional Arabian incense can leave people more susceptible to headaches, forgetfulness and concentration problems, a study has found. A study of indoor air pollution in homes across the Emirates has found people who burn incense such as oud and bakhour each day are two to four times more likely to suffer such symptoms. "Incense is so common in the Arabian Peninsula, it really does beg further research," said Karin Yeatts, who conducted the study. It was commissioned as part of a wider investigation into air pollution by the Environment Agency - Abu Dhabi (Ead). The study was published in February in the online journal Environmental Health Perspectives. Researchers visited 628 Emirati households across the country to interview 1,590 people over eight months in 2009-2010. They installed air-quality gauges in homes and conducted interviews on tobacco consumption, burning of incense and use of gas stoves. The study found 86 per cent of Emirati households burnt incense at least once a week, and 44 per cent once a day. Twenty-nine per cent of respondents lived in homes where significant traces of formaldehyde was found in the air, and 30 per cent had significant amounts of sulphur dioxide in their homes. Formaldehyde exposure has been associated with neurological symptoms such as headaches and dizziness, while sulphur dioxide, which is produced by burning coals, can cause severe respiratory problems. The study found the presence of sulphur dioxide was twice as likely in houses where people burnt incense two or more times a week. Formaldehyde and hydrogen sulphide, another highly poisonous gas, were three times as likely to be found in those houses. Ms Yeatts could not say whether there was a definite relationship. "We can't say conclusively. It needs to be looked into further," she said. "There might be certain types that are less toxic than others. "I wouldn't say that people should stop burning incense right away. Perhaps they can open a window to increase the circulation in the room afterwards." Ms Yeatts, an assistant research professor at the University of North Carolina, said she was working on separate research into the pollutants emitted by bakhour and oud, and she expected research would be published on the subject in the next year. In Saudi Arabia, one study showed Arabian incense seriously damaged the lungs of lab rats. A second study found prolonged exposure to the perfumed smoke caused drastic changes in the rats' metabolisms. "Two types of gases, sulphur dioxide and carbon monoxide, are emitted during the burning of bakhour," said Dr Sayed Oraby, a consultant pulmonologist at Jeddah's Dr Erfan & Bagedo General Hospital who has also conducted research on the incense. "These are very harmful to the respiratory tract. They are burnt quite regularly - it's a very common habit. However, not many people know about the dangers. "Carbon monoxide in particular is poisonous to people. It's exactly the same gas that comes out from the exhaust of cars." Ead said the study was commissioned as part of a multidisciplinary approach, assessing the risks that people in the Emirates faced from environmental factors. "The aim is to assess the main environmental risk factors for human health and help the UAE plan for policies that will address the issues," the agency said. Overall, "the study measured a number of environmental parameters such as food, water, marine-water quality, indoor air quality and outdoor air quality. "It concluded that the UAE doesn't face serious environmental burden of disease threat." * With additional reporting by Vesela Todorova