Michiko Koyano

Estimation of Indoor Air PAH Concentration Increases by Cigarette, Incense-Stick, and Mosquito-Repellent-Incense Smoke

Abstract Smoke from cigarette smoking and burning of incense sticks and mosquito-repellent incense, which is particularly used in summer, are thought to be primary factors of indoor air pollution by polycyclic aromatic hydrocarbons (PAHs) in Japanese houses. In this study, these respective smokes as indoor air pollutants were evaluated by quantifying their particulate matter (PM) and 7 PAHs. PM and PAHs in smoke from 5 popular brands of Japanese cigarettes were collected on the glass fiber filter by the international smoking mode. PM was quantified by weighing the filter before and after trapping them. PAHs were analyzed by HPLC after extracting the filter with ethanol/benzene (1:3, by vol.). Similarly, evaluation of smoke respectively generated by natural burning of 4 brands of incense sticks and 3 brands of mosquito-repellent incenses was also conducted. As the results of these experiments, the average concentrations of PM and benzo[a]pyrene in a 35 m3 closed room were estimated to increase 1630 μg/m3 and 8.2 ng/m3, respectively, by smoking of 3 cigarettes; 1320 μ/m3 and 4.1 ng/m3, respectively, by burning of 2 incense sticks; and 2510 μg/m3 and 17.3 ng/m3, respectively, by burning of 8 cm of mosquito-repellent incense.

Ubiquitous presence of mutagenic and antimutagenic components in air-borne particulates of two Japanese cities

Previous studies on several samples of urban air-borne particulates showed that the long-chain fatty acids present in these samples can interfere with the measurement of mutagenicity of the particulates with the Salmonella assay. To explore whether this phenomenon is a general, fatty acid contents and the mutagenicity (with Salmonella typhimurium TA98 without S9) were measured for 34 particulate samples collected in the cities of Okayama and Tokyo over a period of 1 year. Palmitic, stearic, oleic and linoleic acids were found in all these samples in this order of amount, and their interference on mutagenicity measurement was eminent, particularly at high doses of the sample. With the use of blue cotton extraction, the mutagenic components can be freed from most of these antimutagenic factors. Significant correlation was found between the number of particulates and the mutagenicity per unit volume of the air. Eight polycyclic aromatic hydrocarbon compounds, including benzo[alpha]pyrene were quantified for these 34 particulate samples. Their contents were too small to account for the observed mutagenicity, suggesting that other polycyclic compounds, possibly involving nitro aromatics, were responsible for the mutagenicity observed. No remarkable differences were noted between Okayama and Tokyo in fatty acid contents, mutagenicity or polycyclic aromatic-hydrocarbon contents of the samples.

POLYCYCLIC AROMATIC HYDROCARBON CONCENTRATIONS OF AIRBORNE PARTICLES IN URBAN AIR OVER THE PAST TWENTY YEARS

To estimate human exposure to hazardous chemicals, it is important to measure the annual trends regarding the concentrations of these compounds in the environment. Airborne particulate samples were collected over the past 20 years (1980–2001) from ambient air using a quartz fiber filter with the help of a high-volume air sampler placed on the top of the National Institute of the Public Health building, Minato-ku, Tokyo, Japan. In the present study, portions of these filter samples were analyzed to investigate the trends regarding the concentration of PAHs in urban air over the sampling period. The concentrations of various PAHs per unit air volume were determined. The concentrations of seven PAHs decreased within the sampling periods, especially in the late 1980s, and slowly decreased from the middle 1990s. The concentrations of seven PAHs were higher in autumn and winter than in the spring and summer.

Effect of Storage Conditions on the Mutagenicity of Human Urine.

Effects of storage conditions on the mutagenicity of human (2 smokers and 3 nonsmokers) urine were examined. Aliquots of urine from each male volunteer were stored at -80, 3, 25 and 40°C for various time points (max. 4 or 8 weeks). All extracts were obtained by the use of the Sep-pak tC18/methanol method. At the end of maximum time points, all extracts were assayed by the pre-incubation method with Salmonella typhimurium YG1024. Some statistical changes of mutagenicity were observed under the storage conditions with 25 and/or 40°C for 1 or 2 weeks by the analysis of variance techniques. However, no statistical changes were observed under -80 and 3°C at least up to 4 weeks (significance level : 0.01). It was suggested that human urine samples for the mutagenicity assay may be practically stored at 3°C at least for 4 weeks.