华北七省市有害重金属大气排放与污染时空变化特征精细化表征及动态来源解析研究

The Region of Seven Provinces in North China (including Beijing and Tianjin municipalities, Hebei, Shanxi, Shandong and Henan provinces, as well as Inner Mongolia Autonomous Region, abbreviated to SPNC region hereafter) has been well known as one of the most polluted regions suffering from frequently heavy haze pollution featured with very high concentrations of PM2.5 and toxic heavy metals (Pb, Cd, Cr, As, Ni, Mn, Sb, etc.), which are identified as carcinogenic substances for human health by WHO. In this study, with multiple methods such as flue gas measurements for selected sources including ultra-low emission power plants, industrial coal-fired boilers and cement plants, as well as field survey and investigation of relevant literature and statistics, we will compile the dynamic databases of activity levels and emission factors which covers major emission sources of PM and typical toxic heavy metals (Pb, Cd, Cr, As, Ni, Mn, Sb, etc.) in the SPNC region, and accordingly to establish the regional emission inventory of PM and typical heavy metals (Pb, Cd, Cr, As, Ni, Mn, Sb, etc.) for the year 2015-2017 and conduct quantitative assessment for the emission inventory uncertainties by adopting Bootstrap and Monte Carlo simulation. Then, with the developed emission inventory as input, we will simulate the temporal and spatial variation characteristics of PM10/PM2.5 and heavy metals concentrations as well as their pollution transmission patterns among different cities in the SPNC region by using WRF-CMAQ models. At the same time, during the varied seasons and typical heavy haze episodes at the selected several key cities (which belong to those of the 28 regional air pollution transmission cities specified by the Chinese Ministry of Environmental Protection), we will carry out synchronously offline PM10/PM2.5/PM1.0 sampling and determine their concentration and chemical occurrences of typical heavy metals by using instrumental measurements such as HPLC-ICP-MS and HPLC-HG-AFS, and investigate their source apportionment and explore their contributions on the formation causes of heavy pollution episodes by using multiple models like PMF and PSCF. Furthermore, we will attempt to establish an integrated dynamic source apportionment method that incorporates positive emission inventory/model simulation with reversed receptor source apportionment methods relying on offline membrane sampling and online continuous monitoring. In addition, based on current situation evaluation for the 2017 reference year and assumptions of three different scenarios, we will forecast and simulate the future trends of emission and pollution characteristics of PM2.5 and heavy metals in SPNC region by the target year of 2020 and 2030. We believe the expected outcomes of this application research work will inevitably provide scientific basis on the comprehensive control of PM10/PM2.5 and the associated toxic heavy metals pollution in North China.

华北地区是我国大气颗粒物（PM）和有害重金属污染最严重地区之一。本项目拟通过开展超低排放电厂、燃煤锅炉、水泥厂等典型源烟气测试和现场调查等方法构建本地化排放因子和活动水平数据库及排放因子置信度等级和清单不确定性评价方法，建立2015-2017年华北七省市大气PM及重金属（铅、镉、铬、砷、镍等）精细网格动态排放清单；将清单输入WRF-CMAQ模式模拟研究并揭示区域大气PM10/PM2.5和重金属污染时空变化特征及城市间传输规律；在重点传输通道城市同步开展不同季节和重污染过程大气颗粒物离线/在线观测和重金属化学形态表征，利用PMF等模型解析其来源及重污染成因贡献；探索研发集成源清单/模式模拟、离线/在线观测等多种技术的区域大气颗粒物及重金属动态综合源解析技术方法。以2017为基准年模拟评估2020-2030年不同情景下重点城市大气颗粒物及重金属排放污染变化趋势，为重金属污染防治提供科学依据。

华北七省市是我国大气颗粒物污染最为严重的区域之一，颗粒物中有害重金属的污染及其对公众健康的危害备受关注。本研究在更新完善的高点源化率活动水平数据和基于燃煤电厂和水泥厂等调研及现场测试获取的本地化排放因子的基础上，结合建立开发的具有自主知识产权的大气颗粒物及有害重金属排放清单核算模型，构建了能够准确反映典型污染源排放特征和空间分布格局改变的华北七省市大气颗粒物及有害重金属（Pb、Cd、Cr、As、Ni、Mn、Sb等）精细网格化动态排放清单，并利用涵盖比对研究、蒙特卡洛模型和模式模拟的不确定性评估体系量化清单的不确定性；以构建排放清单为输入，利用WRF-CMAQ模型对大气颗粒物及有害重金属的环境浓度进行数值模拟，揭示了华北重污染地区大气颗粒物及有害重金属污染时空分布特征及城市间的污染输送规律；选取京津冀大气污染传输通道典型城市（北京、保定、郑州、新乡等）开展典型季节和重污染时段的大气颗粒物（PM10/PM2.5/PM1.0）及有害重金属离线膜采样和在线观测，探究了华北七省市大气颗粒物及有害重金属的污染空间分布特征、季节变化规律和典型重金属在不同粒径颗粒物上的富集特征；结合所构建精细网格化排放清单和开展的离线/在线多点位观测，综合利用正向源追踪数值模拟技术和PMF、PSCF等受体模型，动态解析了北京等典型城市重污染过程的主要排放源贡献率和污染传输特征；同时，利用全球暴露死亡模型（GEMM）和美国环保署（US EPA）风险暴露评价模型，对大气颗粒物及有害重金属的相关健康风险进行了量化评估。研究在大气颗粒物及有害重金属排放水平、分布特征及来源解析等方面的关键数据及重要结果，可为大气颗粒物及有害重金属污染防治提供科学依据。项目共培养6名博士生（已毕业3人），14名硕士生（已毕业7人）。项目执行期间，在ES&T、JGR、EP、STOTEN、中国环境科学等国内外知名期刊整理发表学术论文27篇，影响因子合计168.2，累计引用490余次（单篇最高引用112次）。其中第一标注论文14篇（含Nature Index论文5篇）。