Could Incense Burned in Church Give You Cancer?

At a funeral service I recently attended, a minister burned incense near the casket of the deceased. When the pleasant odor reached my nostrils, I inhaled deeply—and then began wondering if I should have. Sure enough, research published this week suggests that breathing in smoke from incense may be harmful. I doubt my exposure during the two-hour service shortened my life span, but it gave me something to think about.

After all, many religions around the world use incense in rituals, and the substance often gets burned in crowded, indoor spaces with limited ventilation. Two years ago, a study (subscription required) found that a Catholic church in Germany contained high concentrations of airborne soot particles during and for several hours after services that involved the burning of incense.

At the time, sources told me that burning incense might put parishioners, especially those with asthma or heart disease, at risk. That's because particulate matter in the air has been linked to heart problems and respiratory conditions.

The latest study on this subject, published Monday, links long-term incense exposure to an increased risk of cancer of the upper respiratory tract. The study involved Singapore Chinese, some of whom may have much greater exposure to incense than most Americans. So the findings may not apply to everyone. In addition, the airborne particles produced by incense used in Singapore may be different from what's used in, say, a Catholic church.

Still, doesn't the finding suggest certain rituals involving incense may be hazardous to the respiratory health of their observant followers?