济南市大气颗粒物背景值确定方法

Estimation of Jinan's Air Particulate Background Concentration

城市大气颗粒物背景值的确定能够为制订城市大气颗粒物污染防治目标提供重要基础支撑,探索大气颗粒物背景值确定方法对于大气污染防治具有重要意义.以济南市清洁对照点跑马岭监测数据为基础,直接采用概率密度法计算得到的ρ(PM10)和ρ(PM_(2.5))背景值范围分别是100～110和40～50μg/m^3.综合应用空气质量模型模拟法和概率密度法,提出基于数值模拟的城市大气颗粒物环境背景值确定方法,并在此基础上确定了济南市大气颗粒物背景值.结果表明:济南市ρ(PM10)和ρ(PM_(2.5))背景值范围分别是30～35和15～20μg/m^3,其中ρ(PM10)环境背景值秋季(40～45μg/m^3)最高、夏季(25～30μg/m^3)最低;ρ(PM_(2.5))环境背景值秋季(25～30μg/m^3)最高、冬季(10～15μg/m^3)最低.研究显示,基于数值模拟计算得到的颗粒物背景值明显低于直接采用概率密度法得到的结果,表明跑马岭受人为因素影响明显,监测结果已不能完全代表济南市大气颗粒物背景值水平;而数值模拟法可以完全剔除了人为源的贡献,计算得到较为准确的ρ(PM10)和ρ(PM_(2.5))背景值.

The estimation of urban air particulates background concentrations plays a very important role in establishing objectives for air particulate pollution prevention.In a clean air site in Paomaling,the concentration ranges of PM 10 and PM 2.5 obtained by using probability density statistics were 100-110 and 40-50μg m 3.An air quality model and probability density statistics were employed in this study,a numerical simulation method to estimate urban air particulate background concentrations was presented,and the air particulate background concentrations in Jinan was determined.The results show that the concentration ranges of PM 10 and PM 2.5 in Jinan are 30-35 and 15-20μg m 3,respectively.The concentrations range of PM 10 in autumn reaches up to 25-30μg m 3,and the minimum value range in summer is 25-30μg m 3;the concentration range of PM 2.5 in autumn reaches up to 25-30μg m 3,and the minimum value range in summer is 10-15μg m 3.The value range obtained by the numerical simulation method is obviously lower than that obtained by probability density statistics,which shows that the Paomaling site is already affected by anthropogenic sources,so the estimation of urban air particulate background concentration cannot truly reflect real values.The numerical simulation method can obtain more accurate results due to eliminating the contribution of anthropogenic sources.