Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (4): 356-362.

Article

### 秸秆燃烧排放PM2.5特征及影响因素研究

1. a. 环境模拟与污染控制国家重点联合实验室 北京大学环境科学与工程学院 北京 100871;
b. 城市人居环境科学与技术重点实验室 北京大学深圳研究生院环境与能源学院 深圳 518055;
c. 郑州大学化学系 郑州 450001
• 投稿日期:2016-01-05 发布日期:2016-02-23
• 通讯作者: 胡敏 E-mail:minhu@pku.edu.cn
• 基金资助:

项目受环保部公益性行业科研专项(No. 201409010)、国家自然科学基金重大项目(Nos. 91544214, 21190052)和中国科学院战略性先导科技专项(No. XDB05010500)资助.

### Characterization and Influence Factors of PM2.5 Emitted from Crop Straw Burning

Wang Yujuea, Hu Mina, Wang Yua, Qin Yanhonga, Chen Hongyangc, Zeng Limina, Lei Jianrongb, Huang Xiaofengb, He Lingyanb, Zhang Ruiqinc, Wu Zhijuna

1. a State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871;
b Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055;
c Department of Chemistry, Zhengzhou University, Zhengzhou 450001
• Received:2016-01-05 Published:2016-02-23
• Supported by:

Project supported by the Nonprofit Research Projects of Environmental Protection Department of China (No. 201409010), the National Natural Science Foundation of China (Nos. 91544214, 21190052) and the Special Fund for Strategic Pilot Technology Chinese Academy of Sciences (No. XDB05010500).

Large quantities of particulate pollutants are emitted into the atmosphere during biomass burning processes. In China, large amounts of agricultural residues are burned in the field during harvest seasons, which influence regional air quality and human health. Corn and wheat are two major crops grown in China, whose burning was simulated in this study. The controlled laboratory simulation of straw burning was performed in the Laboratory of Biomass Burning Simulation at Peking University Shenzhen Graduate School. The burning simulation system was improved and verified. Straw burning aerosols (PM2.5) samples were collected and measured by gravimetric method. Organic carbon (OC) and elemental carbon (EC) were measured by thermal/optical method. Water-soluble inorganic ions and organic matter were measured by ion chromatography. Emission level, characterization and influence factors of crop straw burning aerosols are discussed. PM2.5 emission factors of corn and wheat straw burning are 1082.8 and 835.7~897.3 mg/kg, respectively. Organic matter (OM), which is calculated by multiplying organic carbon (OC) by 1.3, is the major component of PM2.5, accounting for 42%~66% of the total mass. Nearly half (37%~50%) of OM are water soluble. Cl- and K+are two major components among water-soluble inorganic ions, accounting for 4%~15% and 2%~14% of total particle mass, respectively. The K+/EC ratio is 0.5~3.8. The proportions of these species in PM2.5 are comparable to previous studies. Straw moisture content and burning temperature influence the emission level and characterization of straw burning aerosols. Emission factors of PM2.5 and OC increase with the increase of straw moisture content because of incomplete burning. With higher moisture content, more thermal energy is used for the evaporation of water, lowering the burning temperature. Then less proportion of K+and Cl- are released from biomass into the smoke. Therefore, their contributions to the particle mass decrease with the increase of straw moisture content. The emissions of PM2.5 and OC/EC by crop straw burning in the field are estimated based on the emission factors obtained in this study. Corn and wheat burning in the field yield 92.7 Gg PM2.5 and 47.5 Gg OC every year in China, accounting for important fractions among the total mass.