河北省国道和省道机动车基于交通流量的尾气排放量估算

河北省各城市均已开展利用机动车保有量等宏观统计数据的城市移动源排放清单编制工作，但尚缺乏对跨省及全省各城市间国省道高时空分辨率的移动源排放清单研究.本研究利用2017年河北省国道、省道日均交通流量监测数据，计算了2017年河北省国道和省道机动车大气污染物排放量.结果表明：2017年河北省国道和省道机动车CO、HC、NO_x、PM_2.5和PM₁₀排放量，与利用宏观统计数据计算得到的全省机动车排放总量相比，分别占27.8%、15.7%、55.6%、58.3%和58.5%.重型货车是国道和省道机动车CO、NO_x、PM_2.5和PM₁₀排放的主要来源.河北省南部国省道的机动车排放量以南部各城市为中心呈网状辐射，东北部沿海地区的排放量主要在沧州-天津-唐山-秦皇岛-承德沿线分布，西北部则主要在保定-张家口-内蒙沿线分布.月均排放量分布情况为1月最高，9月最低；周日均分布情况为周一—周三逐日增加，周四开始回落，周日降至最低；每日小时平均分布呈现明显的双高峰现象，两次高峰分别出现在11：00和18：00左右；最低值出现在凌晨4：00.河北省内，各市国省道机动车污染物排放分担率前3位的依次为保定、沧州和张家口.跨省交通车辆排放的CO、HC、NO_x、PM_2.5、PM₁₀分别占河北省国省道机动车总排放量的48.1%、48.7%、42.9%、41.3%和41.3%，其中天津市出入河北省的车辆排放分担率最高，其次是北京.京津冀应在区域层面建立机动车污染联合防治协调机制，从调整区域货运交通运输结构、推动柴油车污染控制措施升级等方面改善区域环境空气质量.

Estimation of vehicle emission based on traffic flow on national and provincial roads in Hebei Province

The urban motor vehicle emission inventory has been established in each cities of Hebei province on the basis of the macro statistical data such as vehicle population, while the research on the emission inventory of the inter-provincial and inter-city roads with high spatial and temporal resolution is still very limited. In the present study, the air pollutant emissions of motor vehicles in Hebei were calculated based on the daily average traffic flow monitoring data of national and provincial roads in 2017. Results showed that the emissions of CO, HC, NO_x, PM_2.5 and PM₁₀ from motor vehicles on national and provincial roads in 2017 accounted for 27%, 15%, 54%, 56% and 57% of the province''s vehicle emissions calculated by using macro statistical data. Heavy trucks were the main emission sources of CO, NO_x, PM_2.5 and PM₁₀ from national and provincial motor vehicles. In southern Hebei, it showed a radiation distribution around the cities for the emission of motor vehicles on the national and provincial roads. In the Northeast coastal areas, the pollutant emissions mainly distributed along Cangzhou-Tianjin-Tangshan-Qinhuangdao-Chengde, while in the northwest of Hebei, mainly distributed along Baoding-Zhangjiakou-Inner Mongolia. The distribution of monthly average emissions reached the highest in January and the lowest in September. The weekly changing of pollutants emissions showed an upward trend from Monday to Wednesday, while decreased from Thursday and then reached the lowest on Sunday. The diurnal variation of pollutants emissions presented an obvious bimodal curve. The peak concentrations were found at 11:00 and 18:00 respectively, and the minimum was observed at 4:00 am. Baoding, Cangzhou and Zhangjiakou were the top three cities in Hebei for the contributions of motor vehicle emissions on national and provincial roads. The emissions of CO, HC, NO_x, PM_2.5 and PM₁₀ from inter-provincial traffic vehicles accounted for 48.1%, 48.7%, 42.9%, 41.3%, and 41.3% of the total emissions from national and provincial vehicles, respectively. The transit vehicles that from Tianjin to Hebei contributed most to the pollutant emissions, followed by those from Beijing. To improve the regional air quality, a coordinated mechanism such as the adjustment of the regional freight transportation structure and promoting of pollution control measures for diesel vehicles should be established in Beijing-Tianjin-Hebei region for the joint prevention and control of motor vehicle pollution.