A single particle aerosol mass spectrometer(SPAMS)was used to accurately quantify the contribution of vehicle non-exhaust emissions to particulate matter at typical road environment.The PM_(2.5),black carbon,meteorolo...A single particle aerosol mass spectrometer(SPAMS)was used to accurately quantify the contribution of vehicle non-exhaust emissions to particulate matter at typical road environment.The PM_(2.5),black carbon,meteorological parameters and traffic flow were recorded during the test period.The daily trend for traffic flow and speed on TEDA Street showed obvious“M”and“W”characteristics.6.3 million particles were captured via the SPAMS,including 1.3 million particles with positive and negative spectral map information.Heavy Metal,High molecular Organic Carbon,Organic Carbon,Mixed Carbon,Elemental Carbon,Rich Potassium,Levo-rotation Glucose,Rich Na,SiO_(3) and other categories were analyzed.The particle number concentration measured by SPAMS showed a good linear correlation with the mass concentrations of PM_(2.5) and BC,which indicates that the particulate matter captured by the SPAMS reflects the pollution level of fine particulate matter.EC,ECOC,OC,HM and crustal dust components were found to show high values from 7:00–9:00 AM,showing that these chemical components are directly or indirectly related to vehicle emissions.Based on the PMF model,7 major factors are resolved.The relative contributions of each factor were determined:vehicle exhaust emission(44.8%),coal-fired source(14.5%),biomass combustion(12.2%),crustal dust(9.4%),ship emission(9.0%),tires wear(6.6%)and brake pads wear(3.5%).The results show that the contribution of vehicle non-exhaust to particulate matter at roadside environment is approximately 10.1%.Vehicle non-exhaust emissions are the focus of future research in the vehicle pollutant emission control field.展开更多
Brake wear is an important but unregulated vehicle-related source of atmospheric particulate matter(PM).The single-particle spectral fingerprints of brake wear particles(BWPs)provide essential information for understa...Brake wear is an important but unregulated vehicle-related source of atmospheric particulate matter(PM).The single-particle spectral fingerprints of brake wear particles(BWPs)provide essential information for understanding their formation mechanism and atmospheric contributions.Herein,we obtained the single-particle mass spectra of BWPs by combining a brake dynamometer with an online single particle aerosol mass spectrometer and quantified real-world BWP emissions through a tunnel observation in Tianjin,China.The pure BWPs mainly include three distinct types of particles,namely,Bacontaining particles,mineral particles,and carbon-containing particles,accounting for 44.2%,43.4%,and 10.3%of the total BWP number concentration,respectively.The diversified mass spectra indicate complex BWP formation pathways,such as mechanical,phase transition,and chemical processes.Notably,the mass spectra of Ba-containing particles are unique,which allows them to serve as an excellent indicator for estimating ambient BWP concentrations.By evaluating this indicator,we find that approximately 4.0%of the PM in the tunnel could be attributable to brake wear;the real-world fleet-average emission factor of 0.28 mg km1 veh1 is consistent with the estimation obtained using the receptor model.The results presented herein can be used to inform assessments of the environmental and health impacts of BWPs to formulate effective emissions control policies.展开更多
To investigate the cause of fine particulate matter(particles with an aerodynamic diameter less than 2.5 um,PM2.5) pollution in the heating season in the North China Plain(specifically Beijing,Tianjin,and Langfang),wa...To investigate the cause of fine particulate matter(particles with an aerodynamic diameter less than 2.5 um,PM2.5) pollution in the heating season in the North China Plain(specifically Beijing,Tianjin,and Langfang),water-soluble ions and carbonaceous components in PM2.5were simultaneously measured by online instruments with 1-hr resolution,from November 15,2016 to March 15,2017.The results showed extreme severity of PM2.5 pollution on a regional scale.Secondary inorganic ions(SNA,i.e.,NO3-+So42+NH4+) dominated the water-soluble ions,accounting for 30%-40% of PM2.5,while the total carbon(TC,i.e.,OC+EC) contributed to 26.5%-30.1% of PM2.5 IN the three cities.SNA were mainly responsible for the increasing PM2.5 pollution compared with organic matter(OM).NO3-was the most abundant species among water-soluble ions,but SO42- played a much more important role in driving the elevated PM2.5 concentrations.The relative humidity(RH) and its precursor SO2 were the key factors affecting the formation of sulfate.Homogeneous reactions dominated the formation of nitrate which was mainly limited by HNO3 in ammonia-rich conditions.Secondary formation and regional transport from the heavily polluted region promoted the growth of PM2.5 concentrations in the formation stage of PM2.5 pollution in Beijing and Langfang.Regional transport or local emissions,along with secondary formation,made great contributions to the PM2.5 pollution in the evolution stage of PM2.5 pollution in Beijing and Langfang.The favourable meteorological conditions and regional transport from a relatively clean region both favored the diffusion of pollutants in all three cities.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42107114 and 42177084)the Tianjin Science and Technology Plan Project(No.20YFZCSN01000)the Fundamental Research Funds for the Central Universities(No.63221411).
文摘A single particle aerosol mass spectrometer(SPAMS)was used to accurately quantify the contribution of vehicle non-exhaust emissions to particulate matter at typical road environment.The PM_(2.5),black carbon,meteorological parameters and traffic flow were recorded during the test period.The daily trend for traffic flow and speed on TEDA Street showed obvious“M”and“W”characteristics.6.3 million particles were captured via the SPAMS,including 1.3 million particles with positive and negative spectral map information.Heavy Metal,High molecular Organic Carbon,Organic Carbon,Mixed Carbon,Elemental Carbon,Rich Potassium,Levo-rotation Glucose,Rich Na,SiO_(3) and other categories were analyzed.The particle number concentration measured by SPAMS showed a good linear correlation with the mass concentrations of PM_(2.5) and BC,which indicates that the particulate matter captured by the SPAMS reflects the pollution level of fine particulate matter.EC,ECOC,OC,HM and crustal dust components were found to show high values from 7:00–9:00 AM,showing that these chemical components are directly or indirectly related to vehicle emissions.Based on the PMF model,7 major factors are resolved.The relative contributions of each factor were determined:vehicle exhaust emission(44.8%),coal-fired source(14.5%),biomass combustion(12.2%),crustal dust(9.4%),ship emission(9.0%),tires wear(6.6%)and brake pads wear(3.5%).The results show that the contribution of vehicle non-exhaust to particulate matter at roadside environment is approximately 10.1%.Vehicle non-exhaust emissions are the focus of future research in the vehicle pollutant emission control field.
基金supported by the National key research and development program of China(2022YFE0135000)the Tianjin Science and Technology Plan Project(19YFZCSF00960)+2 种基金the National Natural Science Foundation of China(42177084,42175123,42107114,42107125)the Natural Science Foundation of Tianjin(20JCYBJC01270)the Fundamental Research Funds for the Central Universities(63221411).
文摘Brake wear is an important but unregulated vehicle-related source of atmospheric particulate matter(PM).The single-particle spectral fingerprints of brake wear particles(BWPs)provide essential information for understanding their formation mechanism and atmospheric contributions.Herein,we obtained the single-particle mass spectra of BWPs by combining a brake dynamometer with an online single particle aerosol mass spectrometer and quantified real-world BWP emissions through a tunnel observation in Tianjin,China.The pure BWPs mainly include three distinct types of particles,namely,Bacontaining particles,mineral particles,and carbon-containing particles,accounting for 44.2%,43.4%,and 10.3%of the total BWP number concentration,respectively.The diversified mass spectra indicate complex BWP formation pathways,such as mechanical,phase transition,and chemical processes.Notably,the mass spectra of Ba-containing particles are unique,which allows them to serve as an excellent indicator for estimating ambient BWP concentrations.By evaluating this indicator,we find that approximately 4.0%of the PM in the tunnel could be attributable to brake wear;the real-world fleet-average emission factor of 0.28 mg km1 veh1 is consistent with the estimation obtained using the receptor model.The results presented herein can be used to inform assessments of the environmental and health impacts of BWPs to formulate effective emissions control policies.
基金supported by the National Natural Science Foundation of China(No.91544226)the National Key Research and Development Plan of China(Nos.2017YFC0209503 and 2016YFC0206202)+1 种基金the National Research Program for Key Issues in Air Pollution Control in China(No.DQGG0107-03)the financial support from CSC(Chinese Scholorship Council)
文摘To investigate the cause of fine particulate matter(particles with an aerodynamic diameter less than 2.5 um,PM2.5) pollution in the heating season in the North China Plain(specifically Beijing,Tianjin,and Langfang),water-soluble ions and carbonaceous components in PM2.5were simultaneously measured by online instruments with 1-hr resolution,from November 15,2016 to March 15,2017.The results showed extreme severity of PM2.5 pollution on a regional scale.Secondary inorganic ions(SNA,i.e.,NO3-+So42+NH4+) dominated the water-soluble ions,accounting for 30%-40% of PM2.5,while the total carbon(TC,i.e.,OC+EC) contributed to 26.5%-30.1% of PM2.5 IN the three cities.SNA were mainly responsible for the increasing PM2.5 pollution compared with organic matter(OM).NO3-was the most abundant species among water-soluble ions,but SO42- played a much more important role in driving the elevated PM2.5 concentrations.The relative humidity(RH) and its precursor SO2 were the key factors affecting the formation of sulfate.Homogeneous reactions dominated the formation of nitrate which was mainly limited by HNO3 in ammonia-rich conditions.Secondary formation and regional transport from the heavily polluted region promoted the growth of PM2.5 concentrations in the formation stage of PM2.5 pollution in Beijing and Langfang.Regional transport or local emissions,along with secondary formation,made great contributions to the PM2.5 pollution in the evolution stage of PM2.5 pollution in Beijing and Langfang.The favourable meteorological conditions and regional transport from a relatively clean region both favored the diffusion of pollutants in all three cities.