Mutagenicity and Nitropyrene Concentration of Indoor Air Particulates Exhausted from a Kerosene Heater

The particulates in a room warmed with a radiant kerosene heater were collected, extracted and fractionated into diethyl ether‐soluble neutral, acidic and basic fractions. The mutagenicity of these fractions was measured with Salmonella typhimurium strains TA98, TA98NR, TA98/1,8‐DNP(6) and TA100 in the presence and ahsence of S9 mix. Room air without the heater showed very low mutagenicity. However, a sample from a room at the beginning of the burning period showed very high mutagenicity (237 His(+) revertants/plate/m(*3) of air in strain TA98 in the absence of S9 mix). In contrast, emissions from the heater after it was burning stably showed low mutagenicity (9 His(+) revertants/plate/m(*3)). The crude extract of particulates from the heater at the beginning of the burning period was analyzed by high‐pressure liquid chromatography (HPLC) and showed a considerable amount of nitropyrenes (NPs); the concentrations of 1‐NP and 1,6‐diNP were 1.62 ng and 0.149 ng/m(*3) of air, respectively, and accounted for 1.2% and 17.6%, respectively, of the mutagenicity in strain TA98 in the absence of S9 mix. In addition, an HPLC‐Ames histogram showed that peaks of mutagenicity corresponding to 1‐NP and diNPs accounted for 75.7% (1‐NP, 4.9%; 1,6‐diNP, 17.1%; 1,8‐diNP, 46.3%; 1,3‐diNP, 7.4%) of the HPLC‐recovered mutagenicity for strain TA98 without S9 mix. These results suggest that kerosene heaters, especially immediately after ignition, create mutagenic substances such as NPs.