Scientists from Maastricht University in Amsterdam found that burning candles and incense in church can release dangerous levels of potentially carcinogenic particles, according to research published this week in the European Respiratory Journal.
"After a day of candle burning we found about 20 times as much as by a busy road," Theo de Kok, the author of the study, told Reuters.
"These levels were so unbelievably high we thought we should report it to the public."
According to AFP, de Kok and his colleagues measured levels of fine particulates in the air of a small chapel and a local basilica after experiments in which they burned candles for nine hours and simulated a service in which incense was burned.
The scientists found that the air at the Maastricht church contained 20 times the European Union limit of PM10 particles after the simulation. PM10 particles, which are so small that they can reach very deep into the lungs, often comprise soot, metals or carcinogens, and can cause a range of problems ranging from cancer to heart disease.
They also found high levels of carcinogenic polycyclic aromatic hydrocarbons as well as some unknown types of free radicals released from burning candles and incense. Free radical atoms act as starters and promoters of cancer tumors. "The exposures are worrisome,¡± said de Kok, ¡°not so much for the occasional churchgoer, but priests, choirs and other people working in churches may have significant exposure."
De Kok said priests at the church in Maastricht had tried to improve ventilation after the study, also noting that some churches had stopped using real candles to protect artwork and delicate interiors.
"It could be an alternative to use fewer candles, better candles, use electric candles or improve ventilation," he said.
According to De Kok, further work is needed to verify these findings, but he believes the discovery is "very worrying" still because it implies that priests and churchworkers--and even devout worshippers who spend several hours each day in church--face the risk of respiratory damage.
De Kok called for research into whether priests, monks and others who work in churches were more prone to lung disease.