Investigation On The Effects Of PM_2.5 And O₃ On Residents’ Respiratory Health In A District Of Nanjing

With the increase of urban population,the accelerated industrial process,and the increased urban traffic pressure,air pollution has gradually become serious.In 2019,air pollution ranked fourth among the leading mortality risk factors in the world^[1],causing 667 million deaths^[2],and the impact of air pollution exposure on population health has received widespread attention.For the past few years,ozone（O₃）andf ine particulate matter(PM_2.5)pollution in a district of Nanjing City,Jiangsu Province has become the most urgent local air quality problem.The health effects caused by air pollution are mainly short-term effects^[3].Considering that there are certain regional differences in the short-term effects of PM_2.5and O₃exposure on human health,the results of previous studies cannot show the actual situation in the study area.Therefore,this study used a generalized additive model based on time series to initially explore the short-term effects of PM_2.5and O₃exposure on residents’respiratory health in a district of Nanjing.And then,this study evaluated PM_2.5and O₃concentrations reaching the Ambient Air Quality Standards of Level 2 in China（CNAQS-2）and the World Health Organization’s Air Quality Guidelines（AQG）scenario health benefits.Finally,On the basis of exposure to PM_2.5and O₃in the study area,the exposure of PM₁₀,NO₂,SO₂,and CO were added to explore the Air Quality Health Index（AQHI）that conforms to the actual local conditionsThe specific research work contents mainly consisted of the four parts:1.Meta-analysis of short-term impacts of PM_2.5and O₃on respiratory healthObjective:To understand the short-term impacts of PM_2.5and O₃exposure on the respiratory health of the population in the past decade,and to provide more new evidence for assessing health effects and improving air quality.Methods:Using air pollution,health outcomes and respiratory diseases（RD）as key words,literature searches were carried out in the core databases of Wan Fang,CNKI,VIP,Pub Med,and Web of Science.The search included global literature investigating the short-term impacts of PM_2.5and O₃exposure on population respiratory health.Using the random effects model to analyze the combined effects of the included studies,and the results of the study took the change unit of every10μg/m³increase in short-term effects of PM_2.5and O₃exposure on human respiratory health.Meta-analysis was performed using R 4.1.3 software.Results:A total of 3938 literature related to the short-term impacts of PM_2.5exposure on population health were retrieved,and 70 eligible literature were finally included,including 57English literature and 13 Chinese literature.A total of 1945 literature related to the short-term impacts of O₃exposure on population health were retrieved,and 27 eligible literature were finally included,including 27 English literature and 0 Chinese literature.The results of random effect model show that with each 10μg/m³increase in PM_2.5,the risk of death from RD increased by1.07%（95%CI:0.85%,1.30%）,and the risk of combined visit rate and hospitalization rate of RD increased by 1.31%（95%CI:0.92%,1.69%）.For every 10μg/m³increase in O₃concentration,the risk of death from RD increased by 1.02%（95%CI:0.53%,1.52%）,and the risk of combined visits and hospitalizations of RD increased by 0.42%（95%CI:0.19%,0.65%）.Sensitivity analysis showed no significant difference.Among them,Egger’s test P<0.05 in the study on the correlation between O₃exposure and the population hospital visit rate and hospitalization rate has publication bias.Conclusion:Meta-analysis results show that exposure to ambient PM_2.5and O₃is associated with population mortality,hospital visits and hospitalizations associated with increased risk.2.Short-term health effects of PM_2.5and O₃on residentsObjective:To explore the short-term effects of PM_2.5and O₃exposure on residents’respiratory health in the study area,quantify the hazards of PM_2.5and O₃exposure to residents’respiratory health,and provide a theoretical basis for local decision-makers to formulate public health measures and improve environmental hygiene.Methods:Using daily outpatient and atmospheric monitoring data from the largest public hospital in the study area from 2017 to 2018,the time series Generalized Additive Model with one-day lag and moving average lag was used to evaluate the relationship between PM_2.5or O₃and outpatient visits with respiratory diseases.Results:For every 10μg/m³increase in PM_2.5,in the single-day lag effect model,the hospital visit rate increased by 0.97%（95%CI:0.59%,1.36%）,and in the moving average lag effect model,the maximum effect value of the visit rate increased by 1.74%（95%CI:1.16%,2.32%）.For every10μg/m³increase in O₃,in the single-day lag effect model,the visit rate increased by 0.85%（95%CI:0.64%,1.05%）,and in the moving average lag effect model,the maximum effect value of the visit rate increased by 1.56%（95%CI:1.21%,1.92%）.Compared with the single-day lag effect of air pollutants,the moving average lag effect is larger and more significant.Women are more susceptible to PM_2.5than men,and men are more susceptible to O₃than women.The patients under the age of 65 were susceptible to PM_2.5and O₃exposure,and the patients under the age of 18 were more sensitive to changes in O₃.Conclusion:The exposure to PM_2.5and O₃in the study area endanger the health of the respiratory system of local residents.There are differences in the susceptibility of susceptible populations to different pollutants.Compared with the single-day lag effect,the cumulative lag effect of air pollutants is larger and more significant.3.Health benefits to residents under PM_2.5and O₃compliance scenariosObjective:To explore the short-term association between PM_2.5and O₃with the Years of Life Lost（YLL）from RD in the study area,and to evaluate the extended life expectancy of local residents when environmental PM_2.5and O₃meet CNAQS-2 and AQG standards.Methods:The generalized additive model of time series analysis was used to explore the effects of PM_2.5and O₃on the respiratory disease YLL of residents in the study area,and stratified analysis by age and gender was carried out.Potential gain in life expectancy（PGLE）and attributable fraction（AF）were used to assess the health benefits to local residents when ambient O₃and PM_2.5met two air quality standards,respectively.Results:When the O₃concentration in the air reaches the CNAQS-2 and AQG standards,the per capita preventable person-years of premature death from respiratory disease may increase by0.90 person-years and 4.68 person-years,respectively.The per capita preventable person-years of premature death for men were 0.07 and 0.36 person-years,and the per capita preventable person-years of premature death for people under 65 years old were 0.68 and 3.54 person-years..PM_2.5-related research results,the difference was not statistically significant（P>0.05）.Conclusion:The AQG resulted in a greater increase in the life expectancy of residents in the study area than the application of the CNAQS-2,suggesting that stricter environmental quality standards would lead to greater health benefits,suggesting that this finding should be reported in future studies.It should be considered when making decisions and revising air quality standards,and reasonably controlling the concentration of local air pollutants.4.Optimization of Air Quality Health IndexObjective:Compare the evaluation performance of daily outpatient data and death data as health outcomes to construct AQHI.Compare the sensitivity of AQI and AQHI to evaluate the impact of air pollutant concentration changes on population health,and explore an indicator that can better communicate health risks to the public.Methods:Using a generalized additive model of time series analysis,two different types of AQHI were constructed by combining the monitored concentrations of air pollutants with daily outpatient data and death data,respectively.The number of daily outpatient visits and the number of daily deaths were compared as indicators of health outcomes to construct AQHI,and the chi-square test was used to compare the ability of AQHI and Air Quality Index（AQI）to predict health.Results:Compared with the number of daily deaths,the number of daily outpatient visits is more suitable as a health outcome to construct an AQHI indicator.The largest effect was seen in lag04,with an increase in the interquartile range（IQR）of AQHI and a 3.77%（95%CI:2.88%,4.68%）increase in the risk of daily respiratory disease visits.0.15%（95%CI:0.11%,0.19%）increased risk of visit for respiratory disease.AQHI and AQI evaluated the good and good rates of air quality by chi-square test,and the results showed that AQHI was more sensitive to changes in air pollutant concentrations than AQI.Conclusion:Compared with the AQI index widely used in China,the AQHI index constructed based on the exposure-response relationship between air pollution in the study area and the health effects of respiratory diseases in the population is more in line with the actual situation of air pollution in the study area and can effectively indicate the health hazards of local pollutant concentration changes to residents.It is recommended that relevant departments conduct further research on AQHI indicators using outpatient data as health outcomes,and explore an indicator that can better communicate health risks to the public.