Objective: To construct an index system of public health risk assessment for air pollution emergency, so as to provide a tool of evaluating the public health risks of air pollution emergency. Methods: Index system of public health risk assessment for air pollution emergency was established through literature review and group discussions. The index system was determined through two rounds of Delphi expert consultations involving specialists in environmental health, toxicology, epidemiology, health emergency response, and atmospheric monitoring. The effectiveness of the consultation was evaluated by positive coefficient, authority coefficient and coordination coefficient. The weights of index were determined using a combination weighting method of the expert scoring method and the entropy weight method. Results: Fifteen experts participated in the consultation, including 11 males and 4 females. There were 8 experts with a doctor degree, 6 experts with a master degree, 1 experts with a bachelor degree. A total of 11 experts with senior professional titles, and 4 experts with associate senior professional titles. The average work experience was (23.73±10.48) years. The expert positive coefficients for the two rounds of consultations were 83.33% and 100%, respectively. The expert authority coefficients were 0.794 and 0.811, respectively. The coefficients of variation for the importance, feasibility, and sensitivity scores of each index in the two rounds of comsultations were 0.097 to 0.352, 0.078 to 0.478, 0.115 to 0.388, and 0.049 to 0.133, 0.052 to 0.153, 0.049 to 0.178, respectively. The Kendall's coefficients of concordance were 0.237 and 0.440 (both with P<0.05) for the two rounds of consultations. The constructed assessment index system included "likelihood" "hazard" "vulnerability" "controllability" with comprehensive weights of 0.206 7, 0.059 6, 0.378 1, and 0.355 5, respectively. Among the 13 second indicators, "monitoring capability" had the highest comprehensive weight of 0.192 6. Among the 40 tertiary indicators, "real-time monitoring of atmospheric pollutants" "retrospective evaluation of early forecasting results" "types, quantities, and combined effects of atmospheric pollutants" "exposure modes of the population to atmospheric pollutants" had relatively high comprehensive weights of 0.089 5, 0.043 1, 0.041 1 and 0.040 3, respectively. Conclusion The constructed index system of public health risk assessment for air pollution emergency can be applied to the public health risk assessment for air pollution emergencies.

Objective: To examine the effects of air pollution on overall mortality, mortality of respiratory diseases, and mortality of circulatory diseases among residents in Hangzhou City. Methods: Residents' mortality data in Hangzhou City from 2014 to 2016 were captured from Zhejiang Provincial Chronic Disease Surveillance Information Management System, and the ambient air quality in Hangzhou City from 2014 to 2016 were collected from Hangzhou Environmental Monitoring Center, while the meteorological monitoring data during the study period were collected from Hangzhou Meteorological Bureau. The effects of PM2.5, PM10, NO2 and SO2 on overall mortality, morality of respiratory diseases and mortality of circulatory diseases were evaluated a generalized additive model (GAM) based on Poisson distribution, and the risk of mortality was described with excess risk (ER) and its 95%CI. Results: The daily M (QR) overall deaths, deaths from respiratory diseases and deaths from circulatory diseases were 111 (30), 16 (9) and 37 (14) persons in Hangzhou City from 2014 to 2016, respectively. A 10 μg/m3 increase in PM2.5, PM10, NO2 and SO2 resulted in 0.47% (95%CI: 0.23%-0.70%), 0.37% (95%CI: 0.21%-0.53%), 1.06% (95%CI: 0.50%-1.61%) and 3.08% (95%CI: 2.18%-3.99%) rises in the risk of overall mortality, 0.60% (95%CI: 0.04%-1.16%), 0.45% (95%CI: 0.06%-0.83%), 2.01% (95%CI: 0.84%-3.20%) and 6.06% (95%CI: 3.80%-8.37%) rises in the risk of mortality of respiratory diseases, and 0.45% (95%CI: 0.08%-0.83%), 0.44% (95%CI: 0.17%-0.71%), 1.43% (95%CI: 0.49%-2.37%) and 3.66% (95%CI: 2.13%-5.22%) rises in the risk of mortality of circulatory diseases, and the greatest effect was observed at a 2-day lag. Multi-pollutant model analysis showed that, after adjustment for PM2.5, NO2 and PM2.5+NO2+SO2, a 10 μg/m3 increase in SO2 resulted in an elevated risk of mortality of respiratory diseases than a single-pollutant model. Conclusions The air pollutants PM10, PM2.5, NO2, and SO2 correlated positively with the risk of overall mortality, mortality of respiratory diseases and mortality of circulatory diseases in Hangzhou City from 2014 to 2016, and the co-existence of multiple pollutants enhanced the effect of SO2 on mortality of respiratory diseases.

Objective: To investigate the effect of long-term exposure of nitrogen dioxide on the incidence of hypertension. Methods: From March to December 2009, 37 386 eligible residents from four cities in northern China (Tianjin, Shenyang, Taiyuan, and Rizhao) were enrolled in a follow-up study by using the random cluster sampling method. Demographic characteristics, lifestyle, history of diseases, and self-report situation of hypertension were collected by using questionnaire. Based on the average annual concentration of NO₂ during the period from the cohort to the onset of hypertension as an estimate of exposure, the effect of NO₂ exposure on hypertension was analyzed by employing Cox proportional hazards model. The interactions between NO₂ exposure and different characteristics (age, sex, body mass index, smoking, alcohol consumption, education, economy, exercise, and fruit intake) were also examined. Results: The baseline age of residents was (43.74±13.78) years, and the body mass index (BMI) was (22.56±2.92) kg/m². During an average follow-up time of 11.40 years, 2 619 (7.0%) new cases of hypertension were reported. The overall mean environmental pollution levels during the study period for the entire cohort was (40.74±17.07) μg/m³. After adjusting for age, sex, BMI, family history of hypertension, socio-economic information, and lifestyle, the hazard ratio (HR) of incident hypertension with a 10 μg/m³ increase of NO₂ was 1.21 (95%CI: 1.18-1.25). Compared with residents aged 60 years and over (HR=1.19, 95%CI: 1.14-1.26), former and current smoking (HR=1.20, 95%CI: 1.14-1.25), and high-frequency fruit consumption (HR=1.17, 95%CI: 1.13-1.21), residents younger than 60 years (HR=1.28, 95%CI: 1.25-1.32), non-smoker (HR=1.23, 95%CI: 1.19-1.27), and low-frequency fruit consumption (HR=1.27, 95%CI: 1.20-1.35) had stronger interaction effect with NO₂ (all P values for interaction<0.05). Conclusion NO₂ exposure may lead to the onset of hypertension, which has a stronger effect on people younger than 60 years old, without smoking history and with low-frequency fruit consumption.

Objective To investigate the effect of long?term exposure of nitrogen dioxide on the incidence of hypertension. Methods From March to December 2009, 37 386 eligible residents from four cities in northern China (Tianjin, Shenyang, Taiyuan, and Rizhao) were enrolled in a follow?up study by using the random cluster sampling method. Demographic characteristics, lifestyle, history of diseases, and self?report situation of hypertension were collected by using questionnaire. Based on the average annual concentration of NO2 during the period from the cohort to the onset of hypertension as an estimate of exposure, the effect of NO2 exposure on hypertension was analyzed by employing Cox proportional hazards model. The interactions between NO2 exposure and different characteristics (age, sex, body mass index, smoking, alcohol consumption, education, economy, exercise, and fruit intake) were also examined. Results The baseline age of residents was (43.74±13.78) years, and the body mass index (BMI) was (22.56±2.92) kg/m2. During an average follow?up time of 11.40 years, 2 619 (7.0%) new cases of hypertension were reported. The overall mean environmental pollution levels during the study period for the entire cohort was (40.74±17.07) μg/m3. After adjusting for age, sex, BMI, family history of hypertension, socio?economic information, and lifestyle, the hazard ratio (HR) of incident hypertension with a 10 μg/m3 increase of NO2 was 1.21 (95%CI:1.18-1.25). Compared with residents aged 60 years and over ( HR=1.19, 95%CI : 1.14-1.26), former and current smoking ( HR=1.20, 95%CI : 1.14-1.25), and high?frequency fruit consumption ( HR=1.17, 95%CI :1.13-1.21), residents younger than 60 years ( HR=1.28, 95%CI : 1.25-1.32), non?smoker ( HR=1.23, 95%CI :1.19-1.27), and low?frequency fruit consumption ( HR=1.27, 95%CI : 1.20-1.35) had stronger interaction effect with NO2 (all P values for interaction<0.05). Conclusion NO2 exposure may lead to the onset of hypertension, which has a stronger effect on people younger than 60 years old, without smoking history and with low?frequency fruit consumption.

Objective To investigate the effect of long?term exposure of nitrogen dioxide on the incidence of hypertension. Methods From March to December 2009, 37 386 eligible residents from four cities in northern China (Tianjin, Shenyang, Taiyuan, and Rizhao) were enrolled in a follow?up study by using the random cluster sampling method. Demographic characteristics, lifestyle, history of diseases, and self?report situation of hypertension were collected by using questionnaire. Based on the average annual concentration of NO2 during the period from the cohort to the onset of hypertension as an estimate of exposure, the effect of NO2 exposure on hypertension was analyzed by employing Cox proportional hazards model. The interactions between NO2 exposure and different characteristics (age, sex, body mass index, smoking, alcohol consumption, education, economy, exercise, and fruit intake) were also examined. Results The baseline age of residents was (43.74±13.78) years, and the body mass index (BMI) was (22.56±2.92) kg/m2. During an average follow?up time of 11.40 years, 2 619 (7.0%) new cases of hypertension were reported. The overall mean environmental pollution levels during the study period for the entire cohort was (40.74±17.07) μg/m3. After adjusting for age, sex, BMI, family history of hypertension, socio?economic information, and lifestyle, the hazard ratio (HR) of incident hypertension with a 10 μg/m3 increase of NO2 was 1.21 (95%CI:1.18-1.25). Compared with residents aged 60 years and over ( HR=1.19, 95%CI : 1.14-1.26), former and current smoking ( HR=1.20, 95%CI : 1.14-1.25), and high?frequency fruit consumption ( HR=1.17, 95%CI :1.13-1.21), residents younger than 60 years ( HR=1.28, 95%CI : 1.25-1.32), non?smoker ( HR=1.23, 95%CI :1.19-1.27), and low?frequency fruit consumption ( HR=1.27, 95%CI : 1.20-1.35) had stronger interaction effect with NO2 (all P values for interaction<0.05). Conclusion NO2 exposure may lead to the onset of hypertension, which has a stronger effect on people younger than 60 years old, without smoking history and with low?frequency fruit consumption.