SLIDE 2 *Academic studies conducted on the emissions of lead and zinc from candles with metal-core wicks (Nriagu and Kim, 2000). For this study, the researchers purchased and tested candles (found in Michigan stores) that had metal-core wicks. Fourteen brands of candles manufactured in the US, Mexico, and China were found to contain lead. Emission rates from candles ranged from 0.52 to 327 :g-lead/ hour, resulting in lead levels in air ranging from 0.02 to 13.1 :g/m 3. Another prominent study, van Alphen (1999), examined emissions and inhalation exposure-based risks for candles having lead wick cores. The mean emission rate was 770 :g-lead/hour, with a range of 450 to 1,130 :g-lead/hour. A candle burned for 3 hours at 1,000 :g-lead/hour in a 50 m 3 room with poor ventilation is estimated to yield a 24-hour lead concentration of 9.9 :g/m 3, and a peak concentration of 42.1 :g/m 3 . OSHA's 50 :g/m 3 PEL is not approached in this study, but again, EPA's outdoor ambient air standard of 1.5 :g/m 3 is exceeded. Sobel et al. (2000a) modeled lead emissions from candles containing lead wicks. After burning multiple candles in a contained room, 24-hour lead concentrations ranged from 15.2 to 54.0 :g/m 3 . The candle containing the least amount of lead produced lead concentrations of 30.6 :g/m 3 in 3 hours. The maximum concentration of 54 :g/m 3 is above the PEL standard of 50 :g/m 3 and EPA's outdoor ambient air quality standard of 1.5 :g/ m 3.
The National Association of Home Builders (NAHB) has historically received an increased number of reports about black soot deposition. A prime suspect is the increased use of candles. The problem is so severe that North America’s largest indoor air quality conference, held in Texas in 1999, featured a workshop that presented the latest research and case studies on the effects of black soot from candles. Soot is a product of incomplete combustion of carbon-containing fuels, usually petroleum-based. The soot not only discolours walls and furniture, it can also contaminate ventilation systems. Although the problems resulting from burning candles can be minimized, the basic problem is that candle flames must contain soot or they will not be bright. Soot is the source of the bright white/yellow light that candles emit. A flame without soot will burn blue, like the flame from a gas stove. Since soot particles are typically very small, they can potentially penetrate the deepest areas of the lung. Researchers caution that the very young, the elderly and those with respiratory diseases like asthma should avoid exposure to candle soot. Research has shown that wax candles and wax usually refers to a variety of organic substances that are solid at ambient temperature but become free-flowing liquids at slightly higher temperatures. The chemical composition of waxes is complex, but normal alkanes are always present in high proportion and molecular weight profiles tend to be
- wide. The main commercial source of wax is crude oil but not all crude oil refiners
produce wax. Most commonly used wax in catholic institutions is Paraffin wax derived from petroleum. It is easy to recover and offesr a wide range of physical properties that can often be tailored by refining processes. Most producers offer two distinct types of petroleum waxes: paraffins, which are distinguished by large, well formed crystals; and microcrystallines, which are higher melting waxes with small, irregular crystals. Microcrystalline wax contains substantial proportions of branched and cyclic saturated hydrocarbons in addition to normal alkanes. Petroleum wax producers also characterize wax by degree of refinement; fully refined paraffin has oil content generally less than 0.5%, and fully-refined micro-crystalline less than 3%. "Slack wax," precursors to the fully refined versions in either case, would have oil content above 3%, and as high as 35% by weight. Paraffin wax produced from petroleum is essentially a pure mixture of normal and iso-alkanes without the esters, acids, etc. found in animal and vegetable- based waxes.