[Study on revision of standard limits for benzene in"Standards for indoor air quality（GB/T 18883-2022）"in China].

Benzene, as a major indoor pollutant, has received widespread attention. In order to better control indoor benzene pollution and protect people's health, the limit value of benzene in the"Standards for indoor air quality (GB/T 18883-2022)'' was reduced from 0.11 mg/m3 to 0.03 mg/m3. This study reviewed and discussed the relevant technical contents of the determination of benzene limit value, including the exposure status of benzene, health effects, and derivation of the limit value. It also proposed prospects for the future direction of formulating indoor air benzene standards.

[Analysis of PM(2.5) main pollutant components and sources in two cities in north and south of China].

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(4)(2-), 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(4)(3-) 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.

[Intervention effect assessment of response to heatwave in communities of four cities, China].

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.

[The study of lymph nodes metastasis and staging of carcinoma of the gastric cardia by computer].

A total of 605 cases of the carcinoma of gastric cardia resected were analysed univariantly using program of analysis for risk states and survival analysis by life table method on IBM-PC computer. The significance of lymph nodes metastasis in different situations concerning prognosis was evaluated. Our results suggest that the lymph nodes with metastasis at the lower part of esophagus should be grouped as N 1 in the TNM staging system for carcinoma of the gastric cardia. We propose a new staging method, using number of lymph nodes metastasis and degree of tumorous infiltration to the adjacent organs as main indices, for the advanced carcinoma of the gastric cardia clinically and pathologically.