AIM To explore the molecular mechanism of hydroquinone genotoxicity in human bronchial epithelial cells and investigate whether human X-ray repair cross complementing group 1 (XRCC1)was involved in protecting cells from the damage caused by hydroquinone. METHODS XRCC1 gene was knocked down by RNA interference and XRCC1-deficient cell was established by transfected recombinant plasmid pEGFP-C1-pU6-dsRNA. Normal human bronchial epithelial cells (normal cells) and cells transfected with the empty vector of pEGFP-C1 (vector cells) were used as the normal control and vector control. All cells were treated with different concentrations of hydroquinone (10-100 μmol·L-1) for 4 h. MTT assay was used to test cell viability and comet assay was used to detect the DNA damage and repairment. RESULTS MTT assay showed that hydroquinone inhibited the growth of cells in a concentration-dependant manner and the survival number of XRCC1-deficient cell was less than that of the two control groups. Comet assay revealed that different concentrations of hydroquinone caused more severe DNA damage in XRCC1-deficient cell line than in control cells and there were no significant difference in the two control groups. CONCLUSION The results suggest XRCC1 be involved in preventing cells from damage caused by hydroquinone.

Objective: To evaluate the intervention effects of response to heatwave in communities of four cities, China. Methods: Baseline survey on heatwave and climate change related knowledge, attitude and practice (KAP) was conducted in the pilot communities in Harbin, Nanjing, Shenzhen and Chongqing, using face-to-face questionnaire interview in November, 2011 to November, 2013. Finally, 1 604 residents were interviewed. Intervention measures were implemented in summers of 2013 and 2014, including delivering early warning information of heatwave health risk and launching health education and promotion. The second survey was conducted in same communities using the same questionnaire and sampling method as baseline survey in November, 2014, and 1 640 residents were interviewed. The Chi-square test was used to compare the demographic characteristics and KAP of community residents between before and after intervention, and the factors that affected the intervention effect were selected by logistic multiple stepwise regression model. Results: The age of the residents interviewed before and after intervention was (46.4 ± 15.5) years and (45.0 ± 15.9) years, respectively. Overall, the residents' awareness rates of heatwave before and after intervention were 70.5% (1 131/1 604) and 82.9% (1 359/1 640) (χ²=69.40, P<0.001). The rate of residents who had wished to receive early warning information increased 6.3% (χ²=41.11, P<0.001), which reached 94.6% (1 551/1 604) after intervention from 88.3% (1 416/1 604) in baseline survey. Both heatwave health risk early warning and health education had big impacts to residents. There were 92.7% (1 105 residents) among the 1 192 residents who had received the early warning information arrange work and rest time according to the early warning information and 93.0% (1 231 residents) among the 1 323 residents who knew about health education activities being conducted in community thought that the community health education activities had made active role in protecting health from heatwaves. After a series of intervention, male had a effect on attitude about hot wave than female in Nanjing and Chongqing, OR (95%CI) were 1.48(1.02-2.16) and 1.45 (1.18-2.05) , respectively; compared with subjects below primary school education, people with college degree or above had higer KAP in all cities (ORs range from 1.18 to 2.05), P<0.05; regular physical exercise (ORs range from 1.39 to 2.70) also had profound impacts on KAP in all cities (P<0.05). Conclusion s Early warning and health education were effective measures to enhance residents' response capacity to climate change.

Objective:To analyze the pollution characteristics and source of fine particulate matter (PM 2.5) in Shenzhen and Taiyuan, two cities in the north and south of China. Methods:PM 2.5 samples were collected from the year of 2017 to 2018. The levels of 10 heavy metal elements (Pb, Al, As, etc.) , 10 water soluble ions (F -, Cl -, SO 42-, etc.) and 16 polycyclic aromatic hydrocarbons (PAHs) (Nap, Acy, Ace, etc.) in PM 2.5 were detected by inductively coupled plasma mass spectrometry (ICP-MS) , ion Chromatography and high Performance Liquid Chromatography respectively. USA commercial carbon analysis was applied to detect organic carbon (OC) and elemental carbon (EC) . Source of PM 2.5 was analyzed by Factor analysis method. Results:The concentrations of Pb, Mn, As, Ni, F -, OC and EC in PM 2.5 of Taiyuan city were significantly higher than those of Shenzhen City, and the concentrations of Na +, Cl -, and PO 43- were lower than those of Shenzhen City ( P<0.05) . Except naphthalene, the concentrations of PAHs in PM 2.5 of Taiyuan city were higher than those of Shenzhen City ( P<0.05) . The main sources of metal elements and water soluble ions in PM 2.5 in Shenzhen included: industry/vehicle exhaust factor (42.64%) , construction/soil factor (34.22%) and ocean factor (17.93%) . PAHs in PM 2.5 in Shenzhen mostly came from fuel oil/vehicle exhaust factor (38.58%) , coal combustion factor (30.78%) and biomass combustion factor (24.38%) . Differently, the main sources of metal elements and water soluble ions in PM 2.5 in Taiyuan included: construction factor (30.26%) , fuel oil and coal combustion factor (24.58%) , secondary particles/soil factor (22.03%) and industry factor (18.89%) . PAHs in PM 2.5 were from fuel oil/vehicle exhaust factor (54.71%) and coal combustion factor (43.54%) in Taiyuan. Conclusion:The sources of PM 2.5 pollution are different between Shenzhen and Taiyuan, the occupational health management must be continuously strengthened, measures should be strengthened contrapuntally on the basis of different pollution sources.

Objective:To analyze the pollution characteristics and source of fine particulate matter (PM 2.5) in Shenzhen and Taiyuan, two cities in the north and south of China. Methods:PM 2.5 samples were collected from the year of 2017 to 2018. The levels of 10 heavy metal elements (Pb, Al, As, etc.) , 10 water soluble ions (F -, Cl -, SO 42-, etc.) and 16 polycyclic aromatic hydrocarbons (PAHs) (Nap, Acy, Ace, etc.) in PM 2.5 were detected by inductively coupled plasma mass spectrometry (ICP-MS) , ion Chromatography and high Performance Liquid Chromatography respectively. USA commercial carbon analysis was applied to detect organic carbon (OC) and elemental carbon (EC) . Source of PM 2.5 was analyzed by Factor analysis method. Results:The concentrations of Pb, Mn, As, Ni, F -, OC and EC in PM 2.5 of Taiyuan city were significantly higher than those of Shenzhen City, and the concentrations of Na +, Cl -, and PO 43- were lower than those of Shenzhen City ( P<0.05) . Except naphthalene, the concentrations of PAHs in PM 2.5 of Taiyuan city were higher than those of Shenzhen City ( P<0.05) . The main sources of metal elements and water soluble ions in PM 2.5 in Shenzhen included: industry/vehicle exhaust factor (42.64%) , construction/soil factor (34.22%) and ocean factor (17.93%) . PAHs in PM 2.5 in Shenzhen mostly came from fuel oil/vehicle exhaust factor (38.58%) , coal combustion factor (30.78%) and biomass combustion factor (24.38%) . Differently, the main sources of metal elements and water soluble ions in PM 2.5 in Taiyuan included: construction factor (30.26%) , fuel oil and coal combustion factor (24.58%) , secondary particles/soil factor (22.03%) and industry factor (18.89%) . PAHs in PM 2.5 were from fuel oil/vehicle exhaust factor (54.71%) and coal combustion factor (43.54%) in Taiyuan. Conclusion:The sources of PM 2.5 pollution are different between Shenzhen and Taiyuan, the occupational health management must be continuously strengthened, measures should be strengthened contrapuntally on the basis of different pollution sources.

Background Metals and metalloids in fine particulate matter (PM_2.5) may cause damage to the respiratory and circulatory systems of the human body, and long-term exposure is prone to causing chronic poisoning, cancer, and other adverse effects. Objective To assess the distribution characteristics of metals and metalloids in outdoor PM_2.5 in a southern city of China, conduct source apportionment, and evaluate the associated health risks, thereby providing theoretical support for further pollution control measures. Methods PM_2.5 samples were collected in districts A, B, and C of a southern China city, and the concentrations of 17 metals and metalloids were detected by inductively coupled plasma-mass spectrometry (ICP-MS). Pollution sources were assessed through enrichment factor and principal components analysis, and the main pollution sources were quantified using absolute principal component scores-multivariate linear regression (APCS-MLR). Health risks were evaluated based on the Technical guide for environmental health risk assessment of chemical exposure (WS/T777—2021). Results The ambient air PM_2.5 concentrations in the city were higher in winter and spring, and lower in summer and autumn. The annual average concentrations of ambient PM_2.5 in districts A, B, and C were 36.7, 31.9, and 24.4 μg·m⁻³, respectively. The ambient PM_2.5 levels in districts B and C were below the second-grade limit set by the Ambient air quality standards (GB 3095—2012). The enrichment factors of cadmium (Cd), aluminum (Al), and antimony (Sb) were greater than 10, those of copper (Cu), lead (Pb), arsenic (As), nickel (Ni), mercury (Hg), and molybdenum (Mo) fell between 1 and 10, and those of manganese (Mn), vanadium (V), chromium (Cr), cobalt (Co), barium (Ba), beryllium (Be), and uranium (U) were below or equal to 1. The comprehensive evaluation of source analysis showed that the main pollution sources in districts A and C and the whole city were coal-burning. In district B, the main pollution source was also coal combustion, followed by industrial process sources and dust sources. The carcinogenic risks of As and Cr were between 1×10⁻⁶ and 1×10⁻⁴. However, the hazard quotients for 15 metals and metalloids in terms of non-carcinogenic risk were below 1. Conclusion Cr and As in the atmospheric PM_2.5 of the city present a certain risk of cancer and should be paid attention to. In addition, preventive control measures should be taken against relevant pollution sources such as industrial emission, dust, and coal burning.