Suburban forest sites are influenced by both biogenic emissions and anthropogenic pollutants from nearby urban areas. This study investigated PM2.5 sources and atmospheric transformation processes using chemical components and stable carbon isotopes (δ13C) at a suburban forest site in southern China. The average PM2.5 concentration was 62.72 ± 28.90 μg/m3, dominated by secondary inorganic aerosols and organic matter. SOC contributed about 53% of OC during the sampling period. PMF identified six major sources, including biomass burning, vehicle emissions, coal combustion, dust, industrial dust, and waste incineration. PSCF results showed that PM2.5 and OC were affected by both local emissions and regional transport in autumn, but mainly by local sources in winter. δ13C analysis indicated that carbonaceous aerosols were primarily derived from C3 plant biomass and vehicular emissions. High WSOC/OC and SOC/OC ratios suggested significant aerosol aging and secondary organic carbon formation, which strongly influenced δ13C variations in PM2.5.

The health effects of trace elements in PM2.5 have been the subject of widespread public concern. In this study, the 18 trace elements in PM2.5 samples collected at a national park were measured to analyze their concentrations, sources, and health risks. The results showed that the average concentration of 18 trace elements was 191.99 ng/m3 (0.89-1638.28). Higher concentrations of crustal elements are associated with northwestern air masses and southeastern air masses, while higher concentrations of anthropogenic elements are associated with southwestern air masses. The total non-carcinogenic risk of the harmful elements was below the acceptable threshold, for both adults (0.723) and children (0.448). The total carcinogenic risk of the hazardous elements was above the safe level for both adults and children, and the carcinogenic risk of the hazardous elements is As > Ni > Cr > Pb. Natural sources, vehicle emissions, coal combustion, biomass combustion, and industrial sources were identified by both the Absolute Principal Component Score-Multiple Linear Regression (APCS-MLR) model and the Positive matrix factorization (PMF) model. Both the APCS-MLR-HRA model and the PMF-HRA model indicated that vehicle emissions and industrial sources were the main contributors to non-carcinogenic risks, while industrial and coal combustion sources were the main contributors to carcinogenic risks. Mn was the main contributor to the non-carcinogenic risk, while As was the main contributor to the carcinogenic risk. Mn and As should be prioritized as control elements to address the higher non-carcinogenic and carcinogenic risks from vehicle emissions, industrial, and coal combustion sources.

To study the effect of fireworks/firecrackers (FF) display on aerosol particles, the chemical composition and morphology of fine aerosol particles (PM2.5) collected in a rural valley of north China in the Chinese New Year's Eve (CNYE) were analyzed. The results showed that PM2.5 was much lower in the 2022 CNYE with little influence by FF due to the strict no-FF display policy for the 2022 Winter Olympic Games. In contrast, PM2.5 was significantly affected by FF display in the 2023 CNYE with the maximum hourly PM2.5 mass concentrations reaching 1200 mu g m(-3). The value was even much higher than that in near-by cities. Chemical analysis showed that organic matter (24.5 wt% of total PM2.5) was the most abundant in the CNYE, followed by K+ (15.3 wt%), SO42- (12.3 wt%), and Cl (9.9 wt%). The mass concentrations of K+, Mg2+, Cu, Sr, and Ba were as 22.0 to 41.4 times as those before the CNYE. The concentrations of elemental carbon, Cl, SO42-, and Ti were as 3.7 to 12.3 times as those before the CNYE. Further analysis by scanning electron microscope coupled with energy dispersive X-ray spectrometer revealed that carbonaceous particles in the CNYE contained more S, Cl, K and heavy metals compared with that before the CNYE. Most of the non-carbonaceous particles in the CNYE were K-rich, Mg-rich, Al-rich, and Ba-rich, with spherical and near-spherical shapes, which were much different from those before the CNYE with irregular shapes. The different morphologies of non-carbonaceous particles can have much different optical properties, which should be further evaluated. The results above suggested that the PM2.5 mass concentration in rural valleys in the CNYE was extremely high in a short time and more attention should be paid in future policy making to improve air quality.

In the spring of 2023, two severe dust events occurred in the coastal city of Qinhuangdao, North China. We investigated organic carbon (OC) and elemental carbon (EC) in PM10 using an OC/EC analyzer and identified the morphology and elemental composition of individual dust particles using a scanning electron microscope coupled with energy-dispersive X-ray (SEM-EDX). Results showed that OC mass concentrations varied significantly from 12.6 µg m−3 to 74.6 µg m−3 and showed a significant positive correlation with the PM10 mass concentration. On average, OC made up 4.6

Particulate pollution is a serious environmental problem in China and has received much attention from the public. Airborne particles were collected during haze days in Beijing from June 2013 to May 2014. The morphology and elemental composition were investigated with transmission electron microscopy coupled with energy dispersive X-ray spectrometry (TEM-EDX). Six types of individual particles were identified, including sulfate particles (35.1%), mineral particles (26.0%), metal particles (13.5%), fly ash (13.2%), organic particles (5.9%), and soot aggregates (5.7%). Non-carbonaceous particles are mainly "S-rich", ranging from 37.4% in spring to 56.7% in summer, with certain amount of "Si-rich", "Ca-rich", "Fe-rich", and "K-rich" particles. The relative number percentage of sulfate particles shows a positive correlation with relative humidity (RH), suggesting that high RH might accelerate the sulfation of individual particles. Based on air mass backward trajectories, the high pollution in Beijing might be influenced by local emissions and air masses from adjacent areas south of Beijing. Air masses from Inner Mongolia carry higher concentrations of mineral particles and alleviate the abundance of "S-rich" and other particles.

A special dust storm characterized by high PM10 mass concentrations (921.9 +/- 632.3 mu g m(-3)) and high relative humidity (RH; 60.1 % +/- 11.1 %) was observed on March 22-24, 2023 at a coastal city of North China. Aerosol particles of PM10 were analyzed by a scanning electron microscope coupled with energy dispersive X-ray and an ion chromatograph. The results showed that individual mineral particles were dominated by clay minerals, followed by quartz, feldspar, and carbonate. Bulk water-soluble inorganic ions analysis showed that SO42- mass concentrations varied from 3.7 mu g m(-3) to 23.3 mu g m(-3) with an average value of 12.4 mu g m(-3). However, their mass ratios to PM10 were relatively stable, being 1.15-2.01 % with an average value of 1.49 % +/- 0.25 %, similar to the value near the dust sources (Tengger Desert). Although S-containing individual mineral dust varied from 5.2 % to 70.7 %, the average weight ratio of S on individual mineral dust was 2.1 %, much lower than that of non-dust periods (11.0 %). The results suggested limited sulfate formation on mineral dust surfaces even under high RH. In contrast, NO3-, which was very limited in dust sources, varied from 0.21 % to 4.11 % of the total PM10 with an average value of 1.61 % +/- 1.07 %. The research highlighted that nitrate formation has exceeded sulfate formation during severe dust storm episodes, which might because the atmospheric compositions in China have changed significantly with a high mass ratio of NO2/SO2 after the implementation of the strict emission control measures.

As an important component of atmospheric particulate matter（PM）, has become a hot spot in the field of aerosol scientific research due to its’ severe environmental and climatic effects. In order to study the characteristics and sources of carbonaceous component in PM 2.5 at the residential areas of Mount Lu Scenic Area, PM 2.5 were collected from December 2, 2019 to October 31, 2020.The OC and EC in PM 2.5 are analyzed using semi-continuous OC/EC analyzer（Sunset Laboratory,USA）. The results showed that the average mass concentration of PM 2.5 was（46.45±18.64） μg·m -3 , in which the average mass concentration of OC and EC were respectively（4.08±1.61） μg·m -3 and（0.23±0.10） μg·m -3 , accounting for 8.78% and 0.50% of the total mass of PM 2.5 . In addition, the pollution level of carbonaceous component in PM 2.5 is generally lower than that of urban areas, and between the value of other typical high mountain background spots in China. The EC tracer method was used to estimate the secondary organic carbon（SOC） in PM 2.5 . It was found that the average concentration of SOC was（1.51±1.22） μg·m -3 , accounting for 33.2% of the OC, indicating that SOC is an important component of OC in PM 2.5 at the residential areas of Mount Lu Scenic Area. The results showed that SOC conversion rate in spring and autumn was lower than that in winter and summer. The concentration of SOC and O 3 in the atmosphere are significantly positively correlated（R=0.566）, indicating that the oxidation reaction of O 3 as an atmospheric oxidant has a greater impact on the formation of SOC. The OC/EC ratio was between 8.3 and 27.6, further indicating that the residential areas of Mount Lu Scenic Area are seriously polluted by secondary pollution. The principal component analysis of carbon composition shows that, in addition to secondary pollution,the contents of OC and EC in residential areas of Mount Lu Scenic Area are affected by coal-fired emission, biomass combustion emission and motor vehicle emission. The results of the backward trajectory analysis show that these primary source emissions mainly come from long-distance transportation.PM 2.5 and its carbonaceous components are significantly affected by the monsoon.During the sampling period, PM 2.5 and its carbonaceous components in residential areas of Mount Lu Scenic Area are affected by the northwest monsoon in winter. Higher concentration of carbonaceous aerosol at Mount Lu scenic area residential areas are mainly affected by the air masses from the north and southwest industrial city. The summer samples are affected by summer wind warm current and the natural pollutants are less. In addition, more summer rainfall can dilute pollutants to some extent,leading to fewer pollutants of air masses reaching at the Mount Lu scenic area residential area. The correlation between OC and EC indicates that the sources of OC and EC are similar in winter and summer, while the source of OC and EC in spring and autumn are more complicated.

近年来,随着高等分析技术的革命性创新、固体地球科学前沿热点问题的不断突破,地理化学专业课程的教学面临新的挑战.为适应新时代人才培养的需求,本文以岩石学课程为例,分析该课程教学体系现状与不足,构建基于"选择目标+优化案例+模拟实践"的线上线下混合教学体系,探讨该教学体系在课程教学与实践中的改革成效.结果表明,该教学体系对提高课程教学质量、培养学生创新能力具有重要的作用,对教学改革具有积极的参考价值.

Trace elements in atmospheric particulate matter play a significant role in air quality, human health, and biogeochemical cycles. In this study, the trace elements (Ca, Al, K, Fe, Na, Mg, Zn, Pb, Mn, Ti, Cu, Cr, Sr, Ni) in PM2.5 samples collected at the summit of Mt. Lushan were analyzed to quantify their abundance, source, transport, and health risks. During the whole sampling period, the major trace elements was Ca, Al, and K. While the trace metals with the lowest concentrations were Sr, Ni, Rb, and Cd. The trace elements were influenced by air mass transport routes, exhibiting an increasing trend of crustal elements in the northwesterly airmass and anthropogenic elements (Zn, Mn, Cu, and Ni) in the easterly air masses. Construction dust, coal + biomass burning, vehicle emission, urban nitrate-rich + urban waste incineration emissions, and soil dust + industry emissions were common sources of PM2.5 on Mt. Lushan. Different air mass transport routes had various source contribution patterns. These results indicate that trace elements at Mt. Lushan are influenced by regional anthropogenic emissions and monsoon-dominated trace element transport. The total resulting cancer risk value that these elements posed were below the acceptable risk value of 1 × 10-6, while the non-carcinogenic risk value (1.72) was higher than the safety level, suggesting that non-carcinogenic effects due to these trace elements inhalation were likely to occur. Vehicle emission and coal + biomass burning were the common dominant sources of non-cancer risks posed by trace elements at Mt. Lushan.

Aerosol ultra-fine and nano-particles are playing essential roles in the evolution of the Earth environment because of their deep connections to the chemical conversions and solar radiation energy transfer in the atmosphere, and have also become an urgent public concern in recent years due to their adverse health effects. Electron microscopes, as major tools being able to accurately identify the physical and chemical characteristics of individual particles in micron and submicron size, have been widely used in aerosol studies, although some barriers remain for their low efficiency and high cost. In this work, current understandings on the physical and chemical characteristics, mixing state and heterogeneous chemical reactions of individual aerosol particles, mainly obtained with electron microscopes, are reviewed. First, the techniques of individual particle analyses are briefly summarized and their advantages and disadvantages are discussed. Then, the morphology and composition of major atmospheric particle types obtained with these techniques and how the information was used to identify particle sources are introduced. The effects of aerosol particles on the environment, climate, human health, and global geochemical cycles are also discussed based on the data from individual particle analyses. Finally, challenges faced in individual particle studies are prospected. CO 2022 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Traffic is a major source of anthropogenic aerosol in urban atmosphere. In this study, aerosol particles were measured with a TEM-EDX system at the roadside of a main road in the northwestern part of Beijing, China, under clear and hazy conditions. Soot, organic, sulfur-rich (S-rich), mineral, and metal particles, as well as the mixtures, were frequently encountered in aerosols. Under hazy conditions, S-rich particles coated with organic matter (S-OM particles) accounted for most of the total particles (15% to 24%), followed by soot particles (18% to 21%), organic particles (17% to 21%), non-mixed S-rich particles (10% to 18%), and S-rich particles with soot-, mineral-, or metal-inclusions (here referred to as S-inclusion particles) (11% to 15%). Under clear conditions, non-mixed S-rich and organic particles were dominant components, while mineral and soot particles were secondary components, among which, ~14% of the total particles had a sulfate core or OM coating; inclusions of mixture particles were often mixed with sulfate cores. In the sulfate core–OM shell structure particles, the ratio of core diameter to the whole particle diameter was ~0.52 under hazy conditions and ~0.60 under clear conditions, indicating a substantial sulfate and organic formation on the particles. Soot particles accounted for 18% to 21% of the total particles. The relative growth of aged soot particles was higher under hazy conditions than under clear conditions. In sum, particles from traffic emissions on a main urban road aged with the formation of sulfate and organic matter.

雨雪冰冻事件是影响中国南方地区农林业生产的主要气象灾害之一.本研究基于负积温与气温低于0℃的降水量与实际观测的冰雪冻害发生频次之间相关关系分析基础上,确定影响江西省森林冰冻灾害的主要气象因子,并采用模糊数学的方法,计算森林冰冻灾害风险评估因子.同时,应用Morlet小波分析和Mann-Kendall突变分析方法,分析江西省森林冰冻灾害风险的年际变化规律.基于负积温与最低气温低于0℃的当日降水量的平均隶属度、纬度和海拔的相关关系,构建了江西森林冰冻灾害风险区划地理函数,利用ArcGIS空间分析工具,采用自然断点法对风险等级进行区划.结果表明,1955-2018年,江西省冰冻灾害发生次数总体呈现减少趋势,冰冻灾害发生与负积温和当日降水量密切相关,利用负积温与低于0℃的降水量的平均隶属度可以有效地评估森林冰冻灾害风险;江西省森林冰冻灾害风险最为严重的区域主要位于武夷山脉、九岭山脉、罗霄山脉、雩山山脉以及庐山等平均海拔>1000 m的山区.该结论可为江西省森林资源管理提供科学依据.

Beijing has been suffering from frequent severe air pollution events, with concentrations affected significantly by the mixed-layer height. Major efforts have been made to study the physico-chemical properties, compositions, and sources of aerosol particles at ground level. However, little is known about the morphology, elemental composition, and mixing state of aerosol particles above the mixed layer. In this work, we collected individual aerosol particles simultaneously at ground level (2 m above ground) and above the mixed layer in urban Beijing (within the Atmospheric Pollution and Human Health in a Chinese Megacity, APHH-Beijing, 2016 winter campaign). The particles were analyzed offline by transmission electron microscopy coupled with energy dispersive X-ray spectroscopy. Our results showed that the relative number contribution of mineral particles to all measured particles was much higher during non-haze periods (42.5 %) than haze periods (18.1 %); in contrast, internally mixed particles contributed more during haze periods (21.9 %) than non-haze periods (7.2 %) at ground level. In addition, more mineral particles were found at ground level than above the mixed-layer height. Around 20 % of individual particles showed core–shell structures during haze periods, whereas only a few core–shell particles were observed during non-haze periods (2 %). The results showed that the particles above the mixed layer were more aged, with a larger proportion of organic particles originating from coal combustion. Our results indicate that a large fraction of the airborne particles above the mixed layer come from surrounding areas influenced by coal combustion activities. This source contributes to the surface particle concentrations in Beijing when polluted air is mixed down to the ground level.

Dust storm particles have been one of the important contributors to global aerosol loading, affecting human health and climate system. Beijing, a megapolitan city, experienced two severe dust storms in spring of 2015, with maximum hourly-mean PM10 mass concentrations exceeding 1000 μg/m3. The first dust storm (Dust 1) was from east area of Gobi Desert about 850 km in the north of Beijing and the second (Dust 2) was from west area of Gobi Desert about 1500 km in the northwest of Beijing. Morphologies and elemental compositions of dust particles were identified using high-resolution electron microscopy. The statistical analysis showed that the number fractions of mineral dust particles during the two dust storm episodes were 85.3% and 95.4%, respectively. Clay minerals were the most abundant among mineral particles, with a number fraction larger than 50%, followed by quartz particles (17.3% and 14.8%) and feldspar. Feldspar and carbonate particles accounted for 14.8% and 3.4% of mineral particles in Dust 1, and 9.9% and 13.6% in Dust 2, with the difference due to the different source areas. When the dust storms directly migrated to Beijing, the occurrence of S-containing mineral particles and the relative weight ratio of S in individual mineral particles were extremely low, indicating limited production of sulfate on the dust-storm particles in the atmosphere, regardless of the differences of source areas, migration paths, and mineralogical components. After the peaks of dust storms passed, the occurrence of S on the mineral particles were much higher, although the relative weight ratios of S in the mineral particles was still very small. This result suggests that most of the mineral particles underwent heterogeneous reactions, but the reaction rates were low.

氮沉降、磷等养分供应和碳输入影响森林土壤有机碳的稳定性.本研究以丘陵山区杉木人工林表层土壤为对象,研究氮沉降与外源养分和碳源耦合对其有机碳矿化和矿质氮释放的后期影响,分别对土壤做以下条件处理:未做处理(CK)、单独添加外源氮[N]、添加外源氮和碳源[N+C]、外源氮和非氮养分添加[N+nutrient]、外源氮、非氮养分和碳源等混合添加[N+both].结果表明:在土壤培养720 d期间,不同处理土壤有机碳矿化积累量随着培养时间的增加呈上升趋势,而矿化速率则逐渐下降;施加360 d后,各组土壤中NH4+-N、NO3--N和矿质氮含量均高于CK,且彼此之间无差异;施加720 d后,各组土壤中NH4+-N含量均高于CK,但无明显差异;土壤中NO3--N和矿质氮含量均高于CK,且[N]处理最高,[N+nutrient]、[N+both]处理次之,最低是[N+C]处理;720 d时土壤中β-葡萄糖苷酶活性依次为[N+both]、[N+C]、CK和[N]处理;土壤中N-乙酰-葡萄胺糖苷酶活性为[N+both]处理显著高于其他处理;土壤中酸性磷酸酶活性为[N+both]、[N+C]处理显著高于[N]处理和CK.在氮沉降背景下,碳和非氮养分的长时间输入将影响土壤有机碳分解,从而减弱森林土壤碳汇功能.

负氧离子不仅对空气质量具有改善作用,而且对人体健康起到重要的影响.通过连续观测九连山国家森林公园空气负氧离子浓度,分析负氧离子浓度的时空变化规律及与各气象要素之间的相互关系.结果 表明,九连山国家森林公园负氧离子浓度水平达到工级标准,对人体健康极有利.原始阔叶林中负氧离子浓度明显高于人工林中负氧离子的浓度,且原始阔叶林和人工林中负氧离子浓度都呈现夏秋高于冬春,夏季最高,冬季最低;早晚浓度明显高于白天浓度的规律.因此九连山国家森林公园适合出游时间为夏秋季,且上午或傍晚最佳.此外,负氧离子的浓度与空气温度、湿度以及降水量都有明显的相关性,同时也受其他气象因素的影响.这些结果可以为推进森林旅游业的建设提供科学支持,特别是自然保护区内负氧离子资源和旅游产品的开发.

[目的]研究选用SPEI(标准化降水蒸散指数)分析庐山自然保护区干旱状况,及其对日本柳杉(Cryptomoria japonica)径向生长的影响,为庐山日本柳杉的生长和林分经营等提供一些理论依据.[方法]通过建立STD(树轮年表)的树轮宽度指数来反映庐山日本柳杉的径向生长量情况,计算分析SPEI来反映庐山自然保护区近几十年来的干旱变化情况.采用Mann-Kendall突变检验、相关性检验分析、小波分析、多元回归等方法探讨研究庐山日本柳杉径向生长量以及干旱变化.[结果]研究发现:(1)在1967—1970年、1977—1981年、2004—2012年庐山日本柳杉生长情况低于预期标准;(2)标准化降水蒸散指数随时间尺度的增大,波动周期越来越长较长,相对而言,SPEI12更为集中、波动较小,能够更好更准确的反映干旱年变化特征.SPEI12反映出庐山1967—1970年达到重旱程度,1978—1980年特旱,2002—2003年中旱,2005—2013年中旱至重旱;(3)树轮宽度指数与月尺度、半年尺度标准化降水蒸散指数呈显著正相关,与年尺度标准化降水蒸散指数呈极显著正相关关系.同时树轮宽度指数与上年8月至当年6月年尺度标准化降水蒸散指数呈显著正相关,其中与当年5月呈极显著正相关.[结论]日本柳杉生长量的周期变化与干旱周期变化接近,日本柳杉生长量变化相对干旱的变化会持续一到两年左右.

Emission from burning coals is one of the major sources of the airborne particles in China. We carried out a study on the rare earth elements (REEs) in the inhalable particulate matter (PM10) emitted from burning coals and soil-coal honeycomb briquettes with different volatile contents and ash yields in a combustion-dilution system. Gravimetric analysis indicates that the equivalent mass concentration of the PM10 emitted from burning the coals is higher than that emitted from burning the briquettes. The ICP-MS analysis indicates that the contents of total REEs in the coal-burning PM10 are lower than those in the briquette-burning PM10. In addition, the contents of the light rare earth elements (LREEs) are higher than those of the heavy rare earth elements (HREEs) in the PM10 emitted from burning the coals and briquettes, demonstrating that the REEs in both the coal-burning and briquette-burning PM10 are dominated by LREEs. The higher contents of total REEs and LREEs in the coal-burning PM10 are associated with the higher ash yields and lower volatile contents in the raw coals. A comparative analysis indicates that the La/Sm ratios in the PM10 emitted from burning the coals and briquettes, being lower than 2, are lower than those in the particles from gasoline-powered vehicle emission.

Air pollution is particularly severe in developing megacities, such as Beijing, where vehicles equipped with modern gasoline-direct-injection (GDI) engines are becoming one of major sources of the pollution. This study presents the characteristics of individual particles emitted by a GDI vehicle and their ageing in a smog chamber under the Beijing urban environment, as part of the Atmospheric Pollution & Human Health (APHH) research programme. Using transmission electron microscopy, we identified the particles emitted from a commercial GDI-engine vehicle running under various conditions, namely cold-start, hot-start, hot stabilized running, idle, and acceleration states. Our results showed that most of the particles were organic, soot, and Ca-rich ones, with small quantities of S-rich and metal-containing particles. In terms of particle size, the particles exhibited a bimodal distribution in number vs size, with one mode at 800–900 nm and the other at 140–240 nm. The numbers of organic particles emitted under hot-start and hot stabilized states were higher than those emitted under other conditions. The number of soot particles was higher under cold-start and acceleration states. Under the idle state, the proportion of Ca-rich particles was highest, although their absolute number was low. In addition to quantifying the types of particles emitted by the engine, we studied the ageing of the particles during 3.5 h of photochemical oxidation in an environmental chamber under the Beijing urban environment. Ageing transformed soot particles into core–shell structures, coated by secondary organic species, while the content of sulfur in Ca-rich and organic particles increased. Overall, the majority of particles from GDI-engine vehicles were organic and soot particles with submicron or nanometric size. The particles were highly reactive; they reacted in the atmosphere and changed their morphology and composition within hours via catalysed acidification that involved gaseous pollutants at high pollution levels in Beijing.Highlights. GDI-engine vehicles emitted a large amount of both primary and secondary organic aerosol (SOA). Higher numbers of organic particles were emitted under hot stabilized running and hot-start states. Sulfate and secondary organic aerosol formed on the surface of primary particles after ageing. Particles aged rapidly by catalysed acidification under high pollution levels in Beijing.

Abstract. Air pollution is particularly severe in developing megacities, such as Beijing, where pollutants from vehicles equipped with modern gasoline direct injection (GDI) engines must be paid enough attention. This study presents the characteristics of individual particles emitted by a GDI gasoline vehicle and their ageing in a smog chamber under the Beijing urban environment, as part of the Atmospheric Pollution & Human Health (APHH) research programme. Using electron microscopy, we identified the particles emitted from a commercial GDI-engine vehicle running under various conditions, namely cold start, hot start, hot stabilized running, idle, and acceleration states. Our results show that most of the particles were organic, soot and Ca-rich ones, with small quantities of S-rich and metal-containing particles. In terms of grain size, the particles exhibited a bimodal distribution in number vs size, with one mode at 800–900 nm, and the other at 140–240 nm. The amounts of organic particles emitted under hot start and hot stabilized states were higher than those emitted under other conditions. The amount of soot particles was higher under cold start and acceleration states. Under the idle state, the proportion of Ca-rich particles was highest, although their absolute number was low. In addition to quantifying the types of particles emitted by the engine, we studied the ageing of the particles during 3.5 hours of photochemical oxidation in an environmental chamber under the Beijing urban environment. Ageing transformed soot particles into core-shell structures, coated by secondary organic species, while the content of sulfur in Ca-rich and organic particles increased. Overall, the majority of particles from GDI-engine vehicles are organic and soot particles with submicron or nanometric size. The particles are highly reactive; they react in the atmosphere and change their morphology and composition within hours via catalyzed acidification that involves gaseous pollutants under high pollution levels in Beijing.