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Black Soot and Candles |
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Several months ago, we published an Indoor Air Currents about candles in educational environments. In it, we made note of several elementary teachers who burned aromatic candles while students were present in the room. Since that time, significant research has been done and a name has even been provided to the phenomenon.
Black Soot Deposition (BSD) is also referred to ask "ghosting" or "carbon tracking." It has become an increasing complaint of homeowners and some building managers during the last year or so. In response to those concerns David Krause, with Indoor Air Solutions in Tampa, Fl has recently authored new research on the issue. The following questions and answers come from Mr. Krause's paper.
Q. Where does the soot come from?
A. Soot is a product of incomplete combustion. Through interviews with those who have experienced BSD, it has become evident that a common source is candles. Results of recent experiments have shown that certain candles can produce up to 100 times more soot than low-soot producing candles.
Q. Why does the soot deposit?
A. The size of soot particles is very fine and when particles collide and grow in size, they gain enough mass to deposit due to gravity. Soot is also attracted to cooler surfaces. This contributes to the soiling of wall surfaces over studs and air conditioning supply vents. Soot particles are also attracted to injection molded plastic items (computer processing units, computer monitors, and even printers).
Q. What are the possible health concerns?
A. Since the particles are less than 1 micron in diameter, they could penetrate the deepest areas of the lung. The US EPA and the State of California have recognized microscopic soot particles as being responsible for aggravation of respiratory illness in the general population.
Q. What can be done to remedy BSD?
A. First, stop burning candles. Next, install pleated or high-efficiency air filtration.
Q. What causes the soot?
A. There are many causes. Some of the more common ones include: candles with long, untrimmed wicks exceeding 1/8th of an inch; candles poured into glass jars or ceramic containers where air deliveries are inconsistent; aromatic, scented wax, containing aromatic hydrocarbons; thick wick, or one with a wire core which keeps the wick upright; a high, erratic flame which is located in an air draft or by a fan or air conditioning vent; multiple wicked candles with thick, erect, wicks.
Q. Is it possible to burn candles without causing BSD
A. Yes, but all candles should always be discouraged in office environments and strictly forbidden in educational facilities containing small children. |
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