Effects Of Haze Weather On The Death Risk Of Respiratory And Circulatory Diseases In Beijing Residents

The idea of "the unity of nature and human" in traditional Chinese medicine,which is particularly reflected in the theory of five circuits and six qi,focuses on the impacts of the natural environment on human life.It is an important issue to explore how to interpret and apply the theory of "the unity of nature and human" by utilizing scientific research methods.In recent years,haze episodes have occurred frequently in China,leading to the increasingly prominent regional air pollution issue,which is characterized by the PM2.5(particulate matter with an aerodynamic diameter of less than 2.5 ?m)pollution.The severe air pollution seriously damages the human health,thus becoming an important research topic of the theory of "the unity of nature and human" nowadays.In this study,we firstly combed and cleared the meaning and formation of fog and haze and its impacts on human health in Huangdi Neijing;then,we explored the impacts of haze weather on respiratory and circulatory mortality in Beijing by utilizing data on meteorological elements,air pollutants and daily mortality.This study is an innovative exploration to investigate the impacts of meteorological conditions on human life reflected in the idea of "the unity of nature and human" and in the theory of five circuits and six qi under the context of modern science.1 Objective(1)Interpreting the meaning,formation and health impacts of fog and haze in Huangdi Neijing;(2)Using visibility as an indicator to estimate the impacts of haze weather on respiratory and circulatory mortality in Beijing and to investigate the modification effects of visibility level,age,gender and season on the mortality effects of haze weather;(3)Exploring the comprehensive impacts of temperature and haze weather on respiratory and circulatory mortality in Beijing.2 Data and methods(1)DataDaily meteorological data and visibility data during 2006 to 2016 in Beijing was obtained from the Beijing Meteorological Bureau.Daily respiratory and circulatory mortality data during 2006 to 2016 in Beijing was obtained from the China Centers for Disease Control and Prevention.Daily average concentrations of PM2.5 during different periods were derived from the Beijing Meteorological Bureau,the US Embassy and the Beijing Municipal Ecological Environment Bureau(http://sthjj.beijing.gov.cn/),respectively.(2)MethodsFirstly,we utilized the generalized additive model(GAM)to establish the exposure-response associations between haze weather and daily mortality.Then,we classified the haze weather into different levels to explore the impacts of slight haze on mortality,grouped the total population by age and gender to explore their modification effects,and stratified the data by season to assess the impacts of haze weather on mortality in different seasons.Moreover,we estimated the comprehensive effects of temperature and haze weather on mortality from two angles.On one hand,we adopted the binary response model and the temperature stratification model to assess the impacts of haze weather on mortality under different temperature levels,thus quantifying the interaction effects of temperature and haze weather on mortality.On the other hand,we classified the atmospheric stability into three levels,including disturbed,normal and stable conditions;then we adopted two indicators,namely attributable fraction and attributable number of deaths,to quantify the mortality burden of temperature and PM2.5 under different atmospheric stabilities.3 Results(1)The implications of fog and haze in Huangdi Neijing actually comprised the fog and haze as well as sand and dust weather in meteorology.The ancients had found that the occurrence of fog and haze caused visual impairment,thus adopting the visibility reduction as the signal of fog and haze.This finding has been demonstrated by scientists and still been used today,which is the theoretical basis for using visibility as an indicator to study the impacts of haze weather on human health.Additionally,concerning the health impacts of fog and haze,Huangdi Neijing focused on the health impacts of meteorological conditions favorable for fog and haze formation.(2)Reduction in visibility was significantly associated with increased respiratory and circulatory mortality risk in Beijing.In the single-day lag pattern,per 1 km decrease in visibility corresponded to a 0.78%(95%CI:0.62-0.95)increase in respiratory mortality and a 0.54%(95%CI:0.45-0.61)increase in circulatory mortality.In the cumulative-day lag pattern,per 1 km decrease in visibility corresponded to a 0.85%(95%CI:0.67-1.03)increase in respiratory mortality and a 0.53%(95%CI:0.44-0.61)increase in circulatory mortality.(3)Visibility stratification results indicated that even for slight haze,reduction in visibility could still increase the respiratory and circulatory mortality risk.(4)Gender stratification results suggested that there was no significant difference in the mortality risks of visibility between males and females.Age stratification results suggested that the elderly(?65 years)diagnosed with circulatory disease was more susceptible to the mortality risks associated with decreased visibility.(5)Season stratification results implied that the acute impacts of visibility on respiratory and circulatory mortality varied by season,with the highest risk in winter.This seasonal pattern reflected the seasonal variations in the characteristics of air pollution emission sources and meteorological conditions that were unfavorable for pollutant dispersion.(6)Particulate matter,particularly PM2.5,not only played an important role in visibility reduction,but also made a significant contribution to the impacts of visibility on mortality.(7)There were interaction effects between temperature and visibility on respiratory and circulatory mortality in Beijing,with extreme low temperatures intensifying the mortality risks of visibility.(8)During 1 March 2009 to 31 December 2016,the mortality burden attributable to temperature and PM2.5 was 23.76%(95%CI:18.96-28.38)for respiratory disease and 17.54%(95%CI:15.22-19.81)for circulatory disease.Among which,cold temperatures were responsible for the highest mortality burden,followed by PM2.5,whereas hot temperatures had the least effects.The synthetical mortality effects of temperature and PM2.5 varied for different atmospheric stabilities.A stable atmosphere posed the strongest synthetical effects of temperature and PM2.5,followed by a disturbed atmosphere,while a normal atmosphere provided comparatively beneficial conditions for human health.4 Conclusions(1)The occurrence of fog and haze can cause visual impairment,thus adopting the visibility reduction as the signal of fog and haze,which has been recorded in Huangdi Neijing.Meteorological conditions are objective factors for the formation of fog and haze.The understandings of meteorological conditions favorable for the formation of fog and haze in meteorology are in line with the associated understandings in Huangdi Neijing.(2)The haze weather indicated by visibility degradation is associated with increased respiratory and circulatory mortality in Beijing.Visibility level,age,season and temperature can modify the impacts of haze weather on mortality.These results indicate that it is applicable to use visibility as an alternative indicator to assess the health impacts of haze weather if air pollutants data is insufficient or not available,particularly in the middle-and low-income countries.(3)For a comprehensive understanding of the impacts of haze weather on human health,it is necessary and imperative to take both the haze itself and the meteorological conditions favorable for haze formation into consideration,which is enlightened by the theory of "the unity of nature and human" in traditional Chinese medicine and the medical-meteorological ideas contained in theory of five circuits and six qi in Huangdi Neijing.