No abstract

In this study, 32 booth attendants (the exposure group) and 21 in pre-job training to become booth attendants (the reference group) were randomly selected from a highway toll station. Personal PAH samplings were conducted on the exposure group on each day during the studied workweek. Pre-shift urinary 1-hydroxylpyrene levels (1-OHP) were measured on the first day of the workweek (BM(pre)) for both the exposure and reference groups, but the post-shift 1-OHP levels were measured on the last day of the workweek (BM(pest)) only for the exposure group. For the exposure group, we found that their mean total PAH exposure level (C(total PAHs)) was 11 400 ng/m3 and that their mean BM(post) was significantly higher than their mean BM(pre) (= 3.02 and 0.910 micromol of 1-OHP/mol of creatinine, respectively). In addition, the mean BM(pre) for the exposure group were higher than that for the reference group (= 0.410 micromol of 1-OHP/mol of creatinine). The above results suggest that vehicle exhaust significantly affects the booth attendants' 1-OHP levels. None of the three personal factors (age, work experience, and smoking habit), except for C(total PAHs), had a significant effect on predicting booth attendants' BM(inc) levels (= BM(post) - BM(pre)) (R2 = 0.57). The above results suggest that urinary 1-OHP could be a suitable biomarker for characterizing workers' PAH exposures. Similarly, we found that none of the three personal characteristics, except for the involved vehicle flow rates and vehicle types, had a significant effect on predicting booth attendants' BM(inc), levels (R2 = 0.60). The above result suggests that the traffic densities of various traffic types could be a suitable surrogate indicator for assessing workers' PAH exposures. Considering that the type of traffic designed for a given type of tollbooth is quite similar all over the world, the results obtained from this study, at least, could be served as a stepping-stone for providing a cheaper and convenient way for assessing traffic PAH exposures in the future.

The atmospheric PM 2.5 , PM 2.5 /PM 10 , PCDD/Fs-WHO 2005 -TEQ, and PCDD/F (polychlorinated dibenzo-p-dioxins and dibenzofuran) phase distributions of 23 cities in southern China, during 2014-2016, were investigated in this study. In general, the cities with higher latitudes had higher PM 2.5 concentrations than those with lower latitudes. During 2014-2016, the lowest three-year average concentrations of PM 2.5 occurred at Sanya and Haikou and were 16.4 and 21.7 µg m -3 , respectively; while the highest concentrations of PM 2.5 was occurred at Wuhan and Luzhou and were 68.8 and 63.1 µg m -3 , respectively. During 2015-2016, the PM 2.5 concentrations of most of cities decreased, but those of five cities (Chengdu, Luzhou, Nanchang, Qujing and Quanzhou) increased, indicting that the air quality of these five cities was still not well controlled. The average R M values of the 23 cities were 5.20, 4.49 and 4.13 in 2014, 2015 and 2016, respectively, which revealed that the PM 2.5 concentrations in the cities of southern China slowly decreased, although they were still far above the WHO air quality regulated standard (10 µg m -3). In general, a city with a higher PM 2.5 concentration was also had a higher PM 2.5 /PM 10 ratio. Among the 23 cities, the six highest three-year averages of total-PCDD/Fs-WHO 2005 -TEQ concentrations were 0.0665, 0.0633, 0.0625, 0.0600, 0.0528 and 0.0526 pg-WHO 2005 -TEQ m -3 in Chengdu, Wuhan, Nanjing, Hefei, Luzhou and Hangzhou, respectively. During 2014, the six cities (Hefei, Nanjing, Wuhan, Guiyang, Shanghai and Chengdu) with the lowest temperatures in winter (an average of 5.4°C), their average particle phase fractions of total-PCDD/Fs-WHO 2005 -TEQ that were approximately 76%, 53%, 71% and 93% in the spring, summer, fall and winter, respectively; while, the six cities (Haikou, Fuzhou, Guangzhou, Nanning, Nanchang and Changsha) with the highest temperatures in summer (an average of 16.5°C), had average particle phase fractions of total-PCDD/Fs-WHO 2005 -TEQ that were approximately 61%, 42%, 57% and 81% in the spring, summer, fall and winter, respectively. The results of this study provide information showing the trends of both atmospheric PM 2.5 and PCDD/Fs in the cities of southern China. In addition, this study provided the overview relating to the PM 2.5 and PCDD/Fs in ambient air of southern China, which was not reported in previous studies. The results of this study were of great importance to present the trends of air quality in China. It is also useful for the establishment of control strategies in the future.