基于激光散射传感器地面走航研究长三角城市大气颗粒物时空变化
- Spatiotemporal Variations of Atmospheric Particulate Matter in Urban Area of the Yangtze River Delta Based on Ground-Based Mobile Monitoring Using Laser Scattering Sensors
- 基金项目：国家重大科研仪器研制项目(No.42327806)；国家重点研发计划(No.2020YFA0607502)；浙江省“领雁”研发攻关计划(No.2022C03073)；重庆市自然科学基金(No.CSTB2023NSCQ-MSX0305)；重庆市教委科学技术研究项目(No.KJZD-M202201402)
- 摘要：为了解城市颗粒物(Particulate matter, PM)浓度的时空变化特征及对人体健康的影响，本研究于2022年5月、7月、11月及2023年2月使用电动自行车携带激光散射传感器进行96次地面走航监测实验，研究长三角城市绍兴市PM浓度的时空变化特征。时间变化结果表明：除冬季PM2.5和PM10质量浓度日变化呈单峰变化外，其它季节受上下班通勤高峰影响，PM2.5和PM10质量浓度日变化均呈现双峰模式，两个峰值分别出现在8:00和21:00，PM2.5和PM10小时质量浓度降幅分别可达到31和34 μg·m-3。秋季和冬季PM2.5和PM10平均质量浓度明显高于春季和夏季，夏季最低。使用估算的PM背景质量浓度对大气PM浓度进行校正后，发现道路源排放并不是大气PM2.5和PM10质量浓度季节差异的原因，不同季节的气象条件变化和人类非交通排放活动更可能导致其季节差异。空间变化结果表明：秋冬季PM2.5质量浓度的空间差异性最明显，最大差值达到68 μg·m-3，机动车尾气排放和餐饮业的烟气排放是城市局部空间PM2.5质量浓度累积的主要原因。夏季PM2.5质量浓度较低且空间分布均匀。PM2.5和PM10质量浓度超世界卫生组织24小时平均浓度限值（PM2.5和PM10的质量浓度限值分别为15和45 μg·m-3）的天数分别占100%和37.5%。基于PM背景质量浓度估算值，结合城市人口日常活动和PM暴露风险进行科学评价分析并量化计算，发现实验期间人体联合风险比始终大于1，这表明道路上活动的人群存在潜在健康危害。
- Abstract：To understand the spatiotemporal variation characteristics of particulate matter (PM) mass concentrations and their impact on human health in urban areas, in total 96 ground-based mobile monitoring experiments using a laser scattering sensor mounted on an electric bicycle in Shaoxing City, located in the Yangtze River Delta during May, July, and November of 2022 and February of 2023, respectively. The temporal variations indicatethat PM2.5 and PM10 mass concentrations exhibited a bimodal daily pattern influenced by peak commuting times at 8:00 and 19:00, except for in winter,. The hourly mass concentration reductions for PM2.5 and PM10 could reach 31 and 34 μg·m-3, respectively. The average mass concentrations of PM2.5 and PM10 in autumn and winter were significantly higher than those in spring and summer, with the lowest level in summer. After corrected the atmospheric PM mass concentrations using estimated background levels, it was found that road emissions were not the primary reason for the seasonal differences in PM2.5 and PM10 mass concentrations while the variations of meteorological conditions and anthropogenic non-traffic emissions mainly cause the seasonal variations. Spatial variation range in PM2.5 mass concentrations was the most pronounced in autumn and winter with a maximum difference of 68 μg·m-3. Motor vehicle exhaust and emissions from the catering industry were identified as the main contributors to the accumulation of PM2.5 in some urban areas. Conversely, PM2.5 mass concentrations in summer were lower and more evenly distributed. Days with PM2.5 and PM10 mass concentrations exceeding the World Health Organization's guideline values (15 μg·m-3 for PM2.5 and 45 μg·m-3 for PM10) accounted for 100% and 37.5%, respectively in Shaoxing. Based on the estimated background PM mass concentrations, a scientific assessment and quantitative analysis were conducted in conjunction with urban population activities and PM exposure risks. the joint risk ratio for human health during the experimental period was consistently greater than 1, suggesting that populations engaged in activities on roads have the potential health risks.
