京津冀地区典型城市大气细颗粒物碳质组分污染特征及来源

Characteristics and Sources of Carbon Pollution of Fine Particulate Matter in Typical Cities in Beijing-Tianjin-Hebei Region

为研究京津冀地区典型城市大气细颗粒物及其碳质组分的时空变化特征及来源,于2016年12月28日—2017年1月22日及2017年7月1—26日,对北京市与石家庄市PM2.5(细颗粒物)及PM1(亚微米颗粒物)进行采集,使用DRI (热光碳分析仪)检测PM2.5与PM1中ρ(OC)与ρ(EC),并对其碳质组分来源进行分析.结果表明:①采样期间,冬、夏两季PM2.5与PM1中ρ(OC)均为石家庄市采样点远高于北京市采样点;冬季PM2.5与PM1中ρ(EC)均为石家庄市采样点高于北京市采样点,夏季则略有不同.②冬季污染日,北京市采样点ρ(PM2.5)与ρ(PM1)均为石家庄市采样点的1.08倍,PM2.5与PM1中的ρ(OC)分别为石家庄市采样点的1.14和1.12倍,石家庄市采样点PM2.5与PM1中ρ(EC)分别为北京市采样点的1.15和1.28倍;冬季重污染日,北京市采样点的ρ(PM2.5)与ρ(PM1)分别为石家庄市采样点的1.03和1.04倍,PM2.5和PM1中的ρ(OC)分别为石家庄市采样点的1.23和1.22倍,石家庄市采样点PM2.5和PM1中的ρ(EC)分别为北京市采样点的1.03和1.16倍.夏季污染日,石家庄市采样点ρ(PM2.5)与ρ(PM1)分别为北京市采样点的1.16和1.30倍,PM2.5与PM1中ρ(OC)分别为北京市采样点的1.64和2.71倍,两个采样点ρ(EC)相近.③冬、夏两季PM2.5与PM1中ρ(SOC)/ρ(OC)均较高,冬季北京市采样点分别为48.09%和54.29%,石家庄市采样点分别为44.98%和48.09%,夏季北京市采样点分别为48.47%和61.50%,石家庄市采样点分别为61.52%和63.55%,表明SOC更易富集于亚微米粒子中.④冬季北京市和石家庄市两个采样点PM2.5与PM1中碳质组分均主要来源于生物质燃烧、燃煤和机动车尾气;夏季北京市采样点PM2.5与PM1中碳质组分主要来源于机动车尾气,石家庄市采样点PM2.5与PM1中碳质组分主要来源于燃煤和机动车尾气.研究显示,北京市和石家庄市两个采样点大气细颗粒物及其碳质组分浓度存在时空分布和污染来源差异.

In order to investigate the spatial-temporal distribution and sources of fine particulate matter and its carbonaceous components in typical cities of Beijing-Tianjin-Hebei Region,daily samples of PM2.5 (fine particles) and PM1 (submicron particles) were collected and analyzed from December 26th,2016 to January 22nd,2017 and from July 1st,2017 to July 26th,2017 in Beijing and Shijiazhuang. ρ (OC)and ρ (EC) were measured by DRI (thermo-optic carbon analyzer). The results indicated that the ρ (OC) of PM2.5 and PM1 in Shijiazhuang was higher than that in Beijing in both seasons. As for ρ (EC),the winter value of Shijiazhuang was greater than that of Beijing,while the summer value was different. On polluted winter days,the ρ (PM2.5) and ρ (PM1) in Beijing were 1. 08 times higher than those in Shijiazhuang. The ρ (OC) of PM2.5 and PM1 in Beijing was 1. 14 and 1. 12 times of Shijiazhuang. The ρ (EC) of Shijiazhuang was 1. 15 and 1. 28 times of Beijing. On heavy polluted days,the ρ (PM2.5) and ρ (PM1) of Beijing was 1. 03 and 1. 04 times of Shijiazhuang. The ρ (OC) of Beijing was 1. 23 and 1. 22 times of Shijiazhuang,while the ρ (EC) of Shijiazhuang was 1. 03 and 1. 16 times of Beijing. In summer,ρ (PM2.5) and ρ (PM1) on polluted days of Shijiazhuang was 1. 16 and 1. 30 times of Beijing,ρ (OC) was 1. 64 and 2. 71 times,while the ρ (EC) was similar to Beijing. The ratios of ρ (SOC) to ρ (OC) in PM2.5 and PM1 during winter were 48. 09%and 54. 29% in Beijing,respectively,while the ratios were 44. 98% and 48. 09% in Shijiazhuang. In summer,they were 48. 47% and61. 50% in Beijing,while 61. 52% and 63. 55% in Shijiazhuang,which indicated the SOC was more easily enriched in submicron particles. Biomass burning,coal consumption,vehicles exhaust and diesel emissions were the four main sources of carbonaceous in PM2.5 and PM1 in the two cities in winter. In the summer of Beijing,vehicles exhaust was the main source of emissions. As for Shijiazhuang,coal consumption and vehicle exhaust were the biggest contributors. The results showed that the particulate matter and its carbon component concentrations were significantly different in the two cities.