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In facing the challenge of PM2.5 pollution across China, an overall macro-evaluation of the spatiotemporal pollution distribution and health risk of PM2.5-bound heavy metals at a national level is urgently needed. This study involved a bibliometric analysis of 8 PM2.5-bound heavy metals (Cd, Cr, Hg, As, Pb, Cu, Zn, Ni) in the 27 major cities across China from 2013 to 2019 that was combined with valid data from the published scientific literature. Based on time weight vector, the spatiotemporal metal distributions and their integrated enrichment factors were analyzed, and then a fuzzy health risk assessment model was established to synthetically screen regional priority control regions/pollutants, and explore the pollution trend. The integrated concentrations of As (19.44 ng/m3) and Cd (4.12 ng/m3) in most cities exceeded the limits of the Chinese Ambient Air Quality Standards, while Hg (0.81 ng/m3) and Pb (137.10 ng/m3) did not. Spatially, PM2.5-bound heavy metal pollution generally increased from southern to northern China, with North and Northwest of China being relatively hot regions. For integrated health risks, children (3.31) faced higher non-carcinogenic risks than adults (1.69), with As, Cd, and Cr as the main contributors. The total carcinogenic risk varied from 4.86 × 10−6 to 1.3 × 10−3. The total carcinogenic risk of 77.78% of major cities has reached Grade V (moderate-high risk) or above, and the risk contributions of Cr and As accounted for the largest proportion. The temporal variations showed that the pollution had a recent declining trend in most cities. Finally, 10 major cities and their corresponding metals were determined as the priority control cities/metals. The targeted risk management policies were developed for the identified hierarchical hot cities and their priority pollutants to control were based on the regional pollution trend and source characteristics. Image 1 • Spatiotemporal heavy metals in PM2.5 was investigated in the Chinese major cities. • Fuzzy exposure assessment model was established to identify hot pollutants/areas. • Integrated heavy metals in PM2.5 increased gradually from south to north China. • Priority control metals were As, Cr, Cd, especially in north and northwest China. • Targeted policies for priority control regions were formulated on source analysis. [ABSTRACT FROM AUTHOR]

Determination of the pulmonary bioaccessible fraction and its induced health risk with respect to the toxic metals present in tobacco smoke is a significant issue, in terms of scientific and proactive management of clean tobacco production and smoker health. China, the world's largest producer and consumer of tobacco, has about 350 million smokers. The four typical toxic metals in the 20 top selling cigarette brands in China were investigated. The mean levels of As, Cd, Ni, and Pb in tobacco were 0.3891 μg/g, 3.8431 μg/g, 2.4356 μg/g, and 2.7718 μg/g, respectively. Pulmonary bioaccessibility was analyzed by extraction using simulated lung fluid (SLF), where the average rates of As, Cd, Ni, and Pb transferring from tobacco to SLF by mainstream smoke (RSLF) were 7.85%, 2.85%, 0.86%, and 3.45%, respectively. Considering the inhalation pathway of mainstream smoke, an improved health risk assessment (HRA) was conducted using local exposure parameters and fuzzification of sensitive variables. With consideration of the exposure differences of smokers, Cd and As were identified as the priority control metals, and B05, B11, B12, and B19 among the 20 brands (named B01–B20) were found to be the priority control brands. Furthermore, it is worth noting that the membership degrees of a small portion of brands which approached 50% could warn decision-makers of potentially misleading uncertainties. The daily consumption limit (DCL) for each studied brand was calculated, under the risk standard value of Level II (1.00E-05), generally ranging from 1 to 4 cigarette(s) per day. Spatially, DCLs in Southern, Southwestern, and Eastern China were relatively lower than those in other regions. At present, it is of significance to establish a national life-cycle supervisory system for Cd and As. Findings about the health risks posed by toxic metals through the tobacco–smoke–lung exposure pathway can provide scientific risk management reference for smokers, related managers, and producers. Image 1 • Toxic metals in the selected 20 Chinese best-selling cigarettes were investigated. • Pulmonary bioaccessibility of toxic metals was analyzed using simulated lung fluid. • Transfer rates from mainstream smoke to simulated lung fluids (RSLF) were detected. • Health risk posed by tobacco metals was assessed with fuzzy theory and RSLF. • Cd and As need priority control and cigarette consumption limits of brands are 1–4/d. [ABSTRACT FROM AUTHOR]

China is home to the world's largest cigarette maker, and with more than 320 million smokers, accounts for a fifth of world annual deaths from smoking-related diseases. Basic tobacco characteristics and its lead (Pb) and cadmium (Cd) contents of the 20 best-selling Chinese cigarette brands were detected using wet digestion-inductively coupled plasma mass spectrometry. Pb and Cd contents of the selected brands of cigarettes ranged from 1.3861 μg/g to 7.7124 μg/g and 2.9137 μg/g to 5.4841 μg/g, respectively, showing a significant correlation with tobacco weight per cigarette. Fuzzy health risk assessment via inhaling pathway of mainstream smoke was carried out for Pb and Cd based on the regional exposure parameters and fuzzification of the key variables. Results indicated the indexes of (non-)carcinogenic risk of tobacco Pb in all studied brands were below the corresponding general acceptable risk criteria, while that of tobacco Cd exceeded. Cd was identified as the priority control metal in the studied cigarettes. Moreover, the maximum membership probabilities of E08, E09, S11, S18 and S19 were in marginal range of 50%–60%, showing existed uncertainties and possibly misleading decision-makers. Spatially, the carcinogenic risks posed by regional cigarette Cd showed a relatively high level in the Southern, Southwestern and Northern China. Based on Level II for carcinogenic risk (1.00E-05), the limit daily consumption and limit concentration of Cd were obtained for each brand, and the result ranges were generally 2–4 cigarettes per day and 0.5–1.7 μg/g. Presently, it is of significance for the related international/local decision-makers to establish a comprehensive supervisory framework and system for Cd (and other typical toxic metals) in cigarettes from its life cycle perspective. Image 1 • 20 best-selling cigarette brands across the Chinese six regions were investigated. • Smoking health risk posed by tobacco Pb and Cd was assessed with fuzzy theory. • Cd in the selected cigarettes was found to pose certain health threats to smokers. • Regional limit concentrations for Cd were established on health risk guidelines. • Daily consumption limits were recommended according to the different brands. [ABSTRACT FROM AUTHOR]