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Xiao H, Ji C, Ding S, Li X. Strategic control of combustion-induced ammonia emissions: A key initiative for substantial PM 2.5 reduction in Tianjin, North China Plain. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 928:172328. [PMID: 38614324 DOI: 10.1016/j.scitotenv.2024.172328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 03/11/2024] [Accepted: 04/06/2024] [Indexed: 04/15/2024]
Abstract
Information on the temporal and spatial variations in the sources of ammonium salts (NH4+), a crucial alkaline component in PM2.5, is limited. Here, we simultaneously collected PM2.5 and gaseous ammonia (NH3) samples in both summer and winter from two sites in Tianjin: an urban site (Tianjin University, TJU) and a suburban site (Binhai New-region, BH). NH3 concentrations, the contents of major water-soluble inorganic ions in PM2.5, and the compositions of ammonium‑nitrogen isotopes (δ15N-NH4+) were measured. As a result, (NH4)2SO4 and NH4NO3 were the predominant forms of NH4+ in PM2.5 during summer and winter, respectively. However, the NH4NO3 concentrations were notably greater at TJU (6.2 ± 7.3 μg m-3) than at BH (3.8 ± 4.7 μg m-3) in summer, with no regional differences observed in winter. Both sites displayed almost half the contribution of c-NH3 (combustion-related NH3) to NH4+, differing from the finding of previous isotope-based studies. This discrepancy could be attributed to the combined effects of NHx isotope fractionation and seasonal δ15N value variations in NH3 sources. The contribution fractions of v-NH3 (volatile NH3) and c-NH3 exhibited similar patterns at both sites seasonally, probably caused by coal combustion for heating in winter and temperature fluctuations. However, the contribution fraction of c-NH3 was lower at BH than at TJU in summer but greater in winter than at TJU. In summer, NH4NO3 was unstable and limited its delivery to TJU from BH, and the high contribution of c-NH3 to NH4+ at TJU could be attributed to local vehicle emissions. In winter, the stable particulate NH4NO3 that formed from the c-NH3 in the upwind area could be transported to the downwind area, increasing the NH4+ concentration at BH. Our study provides valuable insights for devising emission mitigation strategies to alleviate the increasing burden of NH3 in the local atmosphere.
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Affiliation(s)
- Hao Xiao
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Chuanwen Ji
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Shiyuan Ding
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Xiaodong Li
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China.
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Xu L, Bao Y, Man H, Zhang Z, Chen J, Shao X, Zhu B, Liu H. Influencing factors on ammonia emissions from gasoline vehicles: A systematic review and meta-analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171467. [PMID: 38447721 DOI: 10.1016/j.scitotenv.2024.171467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/18/2024] [Accepted: 03/02/2024] [Indexed: 03/08/2024]
Abstract
Ammonia, a significant precursor for secondary inorganic aerosols, plays a pivotal role in new particle formation. Inventories and source apportionment studies have identified vehicular exhaust as a primary source of atmospheric ammonia in urban regions. Existing research on the factors influencing ammonia emissions from gasoline vehicles exhibits substantial inconsistencies in both test results and analyses. The lack of a uniform pattern in ammonia emissions across different standard vehicles and the significant overlap in test results across diverse operational conditions highlight the complexities in this field of study. While individual results can be interpreted through a mechanistic lens, disparate studies often lack a common explanatory framework. To address this gap, our study leverages the robust and comprehensive approach of meta-analysis to reconcile these inconsistencies and provide a more precise understanding of the factors influencing ammonia emissions from gasoline vehicles. A large number (N = 537) of ammonia emission factors were extracted after screening >1628 publications. The combined ammonia emission factor was 23.57 ± 24.94 mg/km. Emission standards, engine type, ambient temperatures, mileage, vehicle speed, and engine displacement have a significant impact on ammonia emission factors, explaining the ammonia emission factor by up to 50.63 %, with speed being the most significant factor. All these factors are attributed to the interplay of catalyst properties, lambda, and residence time (space velocity). In the current fleet, ammonia emission control is relatively insufficient under low-speed and ultra-high speed, low temperature, and ultra-high mileage conditions. Since ammonia emission factors do not monotonically decrease with the upgrading of motor vehicle emission standards, it is called for the addition of ammonia emission factors indicators in motor vehicle emission standards, and stipulation of targeted testing procedures and testing instruments.
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Affiliation(s)
- Lizhong Xu
- College of Environmental and Resource Sciences, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China; Digital Fujian Internet-of-things Laboratory of Environmental Monitoring, Fuzhou 350007, China
| | - Yumeng Bao
- College of Environmental and Resource Sciences, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China
| | - Hanyang Man
- College of Environmental and Resource Sciences, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China; Digital Fujian Internet-of-things Laboratory of Environmental Monitoring, Fuzhou 350007, China.
| | - Zhining Zhang
- State Key Joint Laboratory of ESPC, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jiawei Chen
- College of Environmental and Resource Sciences, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China
| | - Xiaohan Shao
- College of Environmental and Resource Sciences, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China
| | - Bo Zhu
- College of Environmental and Resource Sciences, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, China; Digital Fujian Internet-of-things Laboratory of Environmental Monitoring, Fuzhou 350007, China
| | - Huan Liu
- State Key Joint Laboratory of ESPC, State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, School of Environment, Tsinghua University, Beijing 100084, China
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Yan F, Chen W, Wang X, Jia S, Mao J, Cao J, Chang M. Significant Increase in Ammonia Emissions in China: Considering Nonagricultural Sectors Based on Isotopic Source Apportionment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:2423-2433. [PMID: 38270134 DOI: 10.1021/acs.est.3c07222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Isotopic source apportionment results revealed that nonagricultural sectors are significant sources of ammonia (NH3) emissions, particularly in urban areas. Unfortunately, nonagricultural sources have been substantially underrepresented in the current anthropogenic NH3 emission inventories (EIs). Here, we propose a novel approach to develop a gridded EI of nonagricultural NH3 in China for 2016 using a combination of isotopic source apportionment results and the emission ratios of carbon monoxide (CO) and NH3. We estimated that isotope-corrected nonagricultural NH3 emissions were 4370 Gg in China in 2016, accounting for an increase in the total NH3 emissions from 7 to 31%. As a result, compared to the original NH3 EI, the annual emissions of total NH3 increased by 35%. Thus, in comparison to the simulation driven by the original NH3 EI, the WRF-Chem model driven by the isotope-corrected NH3 EI has reduced the model biases in the surface concentrations and dry deposition flux of reduced nitrogen (NHx = gaseous NH3 + particulate NH4+) by 23 and 31%, respectively. This study may have wide-ranging implications for formulating targeted strategies for nonagricultural NH3 emissions controls, making it facilitate the achievement of simultaneously alleviating nitrogen deposition and atmospheric pollution in the future.
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Affiliation(s)
- Fenghua Yan
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Weihua Chen
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Xuemei Wang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Shiguo Jia
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou 510275, China
| | - Jingying Mao
- Scientific Research Academy of Guangxi Environmental Protection, Nanning 530022, China
| | - Jiachen Cao
- School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Ming Chang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
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