Health Impacts Assessment Of Major Air Pollutants In The Five Provinces Along Huaihe River In China Based On Satellite Observations

With the development of social economy,air pollution has become a serious environmental problem in China.Air pollutants refer to foreign substances that enter the near-surface or low-level atmospheric environment as a gaseous form.They may have negative impacts on human health and the living environment depending on their concentrations and the exposure time.Understanding the health impacts attributed to air pollutants is critical to environmental impact assessment and pollution management.Regarding to air pollutants,since the human body is exposed to the entire air environment,the health imapct study of multiple air pollutants is more conducive to a comprehensive understanding of the health hazards of regional air pollution than a single pollutant.Therefore,this study took PM_2.5（particulate matters with diameter equal or less than 2.5 micron）,PM₁₀（particulate matters with diameter equal or less than 10 micron）,NO₂（nitrogen dioxide）and SO₂（sulfur dioxide）as the research objects of health impact assessment.They are the major air pollutants that must be included in the calculation of air pollution index stipulated by the environmental protection department.Respect to data sources,the traditional pollutant concentrations used for health impact assessment were mainly from the environmental monitoring stations with limited quantity and uneven distribution,which was difficult to reflect regional air pollution.However,satellite observation data can obtain the spatial distribution of multiple air pollutants in a long time due to its space-time continuity.In this way,the spatial distribution of the health impacts attributed to air pollutants can be further obtained,which compensates for the deficiency of single air pollutants in the coarse area of provinces（cities）in most epidemiological studies.For research area selection,this study replaced the common specific city research with regional research,and selected the five provinces of the Huaihe River Basin（Henan,Hubei,Anhui,Jiangsu,and Shandong）with serious air pollution,dense population and frequent diseases as the study area（referred to as“the five provinces along Huaihe River”）.Based on multi-source satellite remote sensing data and various meteorological parameters,this study estimated the ground-level concentrations of PM_2.5,PM₁₀,NO₂and SO₂ in the five provinces along Huaihe River from 2015 to 2017 using a seasonally geographical weighted regression（GWR）model.Moreover,using respiratory disease death and cardiovascular disease death as two health endpoints,the Health Impact Assessment（HIA）method was used to combine the ground-level concentrations of air pollutants with actual population distribution to assess the health impacts attributed to multiple air pollutants.On this basis,the air pollution situation,the spatial distribution characteristics and interannual variation trends of related health impacts in the five provinces along Huaihe River were further analyzed.The main research results were as follows:（1）The satellite remote sensing products all showed obvious seasonal difference in the five provinces along Huaihe River.AOD（Aerosol Optical Depth）had the largest range of high value in spring and the smallest range in winter,while the tropospheric NO₂ column concentrations and the PBL（planetary boundary layer）SO₂ column concentrations were the highest in winter and the lowest in summer.The seasonal differences were mainly related to topographic factors,climatic conditions and human activities.Therefore,the seasonal variation characteristics of air pollutants and the meteorological parameters should be considered when estimating the ground-level concentrations of air pollutants based on satellite remote sensing products.（2）Based on the seasonally GWR model,the ground-level concentrations of four major air pollutants from 2015 to 2017 were estimated,with a spatial resolution of0.125°×0.125°.There was a high correlation and a lower verification error between the estimated results and the measured values.The spatial distribution trend of ground-level concentration of air pollutants were similar to that of the corresponding satellite remote sensing products.The high-value areas were concentrated in the North China Plain of Henan and Shandong provinces,and the concentration was low in the mountainous areas with good vegetation coverage.PM_2.5 and PM₁₀ were the primary air pollutants in the five provinces along Huaihe River,followed by NO₂ and SO₂.From2015 to 2017,the annual average concentrations of PM_2.5,PM₁₀ and SO₂ all showed a downward trend,while NO₂ increased year by year.（3）According to the exposure-response relationaship published in the literature,the health impacts caused by air pollution in the five provinces along Huaihe River were evaluated.The cause of death analysis showed that the health impacts of air pollutants on cardiovascular diseases were greater than those on respiratory diseases.In terms of air pollutants,the health impacts of particulate matter(PM_2.5 and PM₁₀)were the largest,accounting for about 60%in the health impact area of respiratory disease in the study area,and more than 80%in the health impact area of cardiovascular disease,significantly higher than NO₂ and SO₂.The health impacts of air pollution were concentrated in northeastern Henan,western Shandong,southern Jiangsu and Wuhan city in Hubei,with little health impacts in western Hubei and southern Anhui.From2015 to 2017,the degree and range of the health impact attributed to PM_2.5,PM₁₀ and SO₂ all showed a downward trend,among which SO₂ decreased most significantly,while NO₂ showed an increasing trend year by year.Based on the estimation of the ground-level concentrations of four major air pollutants in the five provinces along Huaihe River from 2015 to 2017,this study assessed the health impacts of air pollutants in combination with the exposure-response relationship.The results are helpful to understand the air pollution status in the study area and the possible health influence area from the spatial pattern,and provide an important reference for the environmental protection and health departments to formulate targeted pollution treatment measures and disease control decisions.