Characteristics of PM_(2.5) and Its Reactive Oxygen Species in Heating Energy Transition and Estimation of Its Impact on the Environment and Health in China——A Case Study in the Fenwei Plain

To reduce the adverse effects of traditional domestic solid fuel,the central government began implementing a clean heating policy in northern China in 2017.Clean coal is an alternative low-cost fuel for rural households at the present stage.In this study,18 households that used lump coal,biomass,and clean coal as the main fuel were selected to evaluate the benefits of clean heating transformation in Tongchuan,an energy city in the Fenwei Plain,China.Both indoor and personal exposure(PE)samples of fine particulate matter(PM_(2.5))were synchronically collected.Compared with the lump coal and biomass groups,the indoor PM_(2.5)concentration in the clean coal group is 43.6%and 20.0%lower,respectively,while the values are 16.8%and 21.3%lower,respectively,in the personal exposure samples.PM_(2.5)-bound elements Cd,Ni,Zn,and Mn strongly correlated with reactive oxygen species(ROS)levels in all fuel groups,indicating that transition metals are the principal components to generate oxidative stress.Using a reliable estimation method,it is predicted that after the substitution of clean coal as a household fuel,the all-cause,cardiovascular,and respiratory disease that causes female deaths per year could be reduced by 16,6,and 3,respectively,in the lump coal group,and 22,8,and 3,respectively,in the biomass group.Even though the promotion of clean coal has led to impressive environmental and health benefits,the efficiencies are still limited.More environmental-friendly energy sources must be promoted in the rural regions of China.

Pioneering observation of atmospheric volatile organic compounds in Hangzhou in eastern China and implications for upcoming 2022 Asian Games

Understanding the emission sources of volatile organic compounds(VOCs)is critical for air pollution mitigation.Continuous measurements of atmospheric VOCs were conducted from January to February in Hangzhou in 2021.The average measured concentration of total VOCs(TVOCs)was 38.2±20.9 ppb,>42% lower than that reported by previous studies at the urban center in Hangzhou.The VOC concentrations and proportions were similar between weekdays and weekends.During the long holidays of the Spring Festival in China,the concentrations of TVOCs were∼50% lower than those during the regular days,but their profiles showed no significant difference(p>0.05).Further,we deduced that aromatics and alkenes were the most crucial chemicals promoting the formation of O3 and secondary organic aerosol(SOA)in Hangzhou.According to interspecies correlations,combustion processes and solvent use were inferred as major VOC emission sources.This study provides implications for air quality improvements before and during the upcoming Asian Games that will be hosted in Hangzhou in 2022.

Development and application of photocatalytic coating for roadside NO_(x) mitigation in Hong Kong

A facile chemical method for the development of photocatalytic coating products was proposed based on practical application perspective for the Hong Kong roadside nitrogen oxides(NO_(x))mitigation.TiO_(2)-based photocatalytic coating PC-C film with crystallized size of around 5–6 nm was synthesized with the peptization of H_(2)O_(2).The PC-C coating possesses a super-hydrophilicity surface and is proven to have a NO_(x)degradation rate of 46.8%with an optimum pH level of 7.In addition,the PC-C coating presents a promising photocatalytic NO_(x)degradation compared with other commercially available coating products and P25 when applied on two building materials of poly-methyl methacrylate(PMMA)and concrete surface.A weather resistance simulation and a 180-day on-site field trial were carried out the attenuation effects of photocatalytic coating applied in outdoor exposure.Based on epidemiological estimation and field investigation,hospital admissions for respiratory diseases(HARD)and mortality cases(MC)could be reduced with the application of PC-C coating along the street canyon.This work demonstrates the feasibility of air pollution control measures for the local roadside NO_(x)using photocatalytic technology,offering promising health benefits with environmental remediation.

Elaborations of the influencing factors on the formation of secondary inorganic aerosols in a heavily polluted urban area of China

In this study,online water-soluble inorganic ions were detected to deduce the formation mechanism of secondary inorganic aerosol in Xianyang,China during wintertime.The dominant inorganic ions of sulfate(SO_(4)^(2-)),nitrate(NO_(3)^(-)),and ammonium(NH_(4)^(+))(the sum of those is abbreviated as SNA)accounted for 17%,21%,and 12% of PM_(2.5)mass,respectively.While the air quality deteriorated from excellent to poor grades,the precursor gas sulfur dioxide(SO_(2))of SO_(4)^(2-)increased and then decreased with a fluctuation,while nitrogen dioxide(NO_(2))and ammonia(NH_(3)),precursors of NO_(3)^(-)and NH_(4)^(+),and SNA show increasing trends.Meteorological factors including boundary layer height(BLH),temperature,and wind speed also show decline trends,except relative humidity(RH).Meanwhile,the secondary conversion ratio shows a remarkable increasing trend,indicating that there was a strong secondary transformation.From the perspective of chemical mechanisms,RH is positively correlated with sulfur oxidation ratios(SOR),nitrogen oxidation ratios(NOR),and ammonia conversion ratios,representing that the increase of humidity could promote the generation of SNA.Notably,SOR and NOR were also positively related to the ammonia.On the one hand,the low wind speed and BLH led to the accumulation of pollutants.On the other hand,the increases of RH and ammonia promoted more formations of SNA and PM_(2.5).The results advance our identification of the contributors to the haze episodes and assist to establish more efficient emission controls in Xianyang,in addition to other cities with similar emission and geographical characteristics.

Growth of nitrate contribution to aerosol pollution during wintertime in Xi'an,northwest China:Formation mechanism and effects of NH_(3)

With the strengthened controls on SO2 emissions and extensive increases in motor vehicles'exhaust,aerosol pollution shifts from sulfate-rich to nitrate-rich in recent years in Xi'an,China.To further gain insights into the factors on nitrate formation and efficiently mitigate air pollution,highly time-resolved observations of water-soluble inorganic ions(WSIIs)in PM_(2.5) were measured in a suburban area of Xi'an,China during wintertime.Hourly concentration of total WSIIs is 39.8μg m-3 on average,accounting for 50.3%of PM_(2.5) mass.In contrast to a slight decrease in the mass fraction of SO42-,NO_(3)-shows a sig-nificant increase of the PM_(2.5) contribution with the aggravation of aerosol pollution.This suggests the importance of NO_(3)-formation to haze evolution.Furthermore,homogeneous reactions govern the formation of NO_(3)-,while alkali metals such as calcium and sodium play an additional role in retaining NO_(3)-in PM_(2.5) during clean periods.However,the heterogeneous hydrolysis reaction contributed more to NO_(3)-formation during the pollution periods under high relative humidity.Our investigation reveals that temperature,relative humidity,oxidant,and ammonia emissions facilitate rapid NO_(3)-formation.Using the random forest(RF)model,NO_(3)-concentrations were successfully simulated with measured variables for the training and testing datasets(R2>0.95).Among these variables,CO,NH_(3),and N02 were found to be the main factors affecting the NO_(3)-concentrations.Compared with the period without vehicle re-striction,the contributions of NO_(3)-and NH4+to PM_(2.5) mass decreased by 5.3%and 3.4%in traffic re-striction periods,respectively.The vehicle restriction leads to the decreases of precursor gases of NO2,SO2,and NH_(3) by 12.8%,5.9%,and 27.6%,respectively.The results demonstrate collaborative emission reduction of NOx and NH_(3) by vehicle restrictions,and using new energy vehicles(or electric vehicles)can effectively alleviate particulate matter pollution in northwest China.

黄山层状云和对流云降水不同高度的雨滴谱统计特征分析

根据2011年6~7月在黄山不同高度采用PARSIVEL雨滴谱仪测得的雨滴谱数据,对不同海拔高度上两类(层状云和对流云)降水粒子谱的微物理特征量、Gamma函数拟合以及雨滴的下落速度进行对比分析,结果表明:对流云降水的雨水含量和降水强度、雨滴的各类尺度参数和数浓度都比相同位置上层状云降水的大,同类降水中,山腰的雨滴尺度大于山顶和山底,这可能与各观测点和云底相对位置的不同有关;随降水强度增加,雨滴的质量加权平均直径Dm逐渐增大,广义截距参数(log10Nw)的标准差逐渐减小。拟合结果表明各高度的雨滴谱都比较符合Gamma分布,由拟合参数分析雨滴谱的演变,发现相对于对流云降水,层状云降水粒子谱随高度的变化较小,雨滴谱的演变较为稳定。此外,本文还对两类降水中雨滴的下落速度及影响落速的因素进行了分析。

近年中国夏季降水变化特征分析

利用台站观测资料和卫星观测换算资料,分析了近年(2002-2004年)中国夏季日内降水量变化统计学特征, 其结果是较为一致的。对于东部大部分地区,日内最强降水易出现在下午到傍晚,对于西部大部分地区易出现在夜晚到清晨。夏季降水以对流降水为主,降水大的地区对应潜热通量也大。由于受观测资料的限制,计算结果有待更多的观测资料来验证。

PM_(2.5)及其测量与影响研究简史

美国率先建立的国家环境空气质量标准(NAAQS)旨在保护公众健康,而该理念已被包括中国在内的众多国家所采用。针对大气悬浮颗粒物(PM),NAAQS根据PM在仪器检测以及人体吸入时的粒径选择性特征,定义了总悬浮颗粒(TSP)、PM_(10)、PM_(2.5)及其相应的质量浓度标准。这些指标的建立是基于长达300年来颗粒物监测技术发展及其危害评价的结果。因此2012年中国在颁布实施新PM_(2.5)空气质量标准时,PM_(2.5)的监测及评价方面有了更多科学积累与技术选择。本文简要回顾了PM的粒径分布、化学组成、可吸入特征、人体健康效应及空气质量标准等研究简史,根据其他国家的发展经验,提出中国在观测网络设计、测量仪器选择和使用、质量控制和质量保证及监测结果分析等方面需要确立自己独特的行业指南。对于未来空气质量的管理和标准制定,应同时考虑多种污染物及其对公众健康、能见度、气候、材料及生态系统的影响。

北京地区一次降雪过程的人工催化数值模拟研究

利用中尺度气象模式WRF的双参数显示云物理方案,开展冬季冷性层状云降水过程的数值模拟和人工增雨催化数值试验。模拟个例为2013年3月19日北京地区的一次典型降水过程,在分析模拟得到的云中水成物和上升速度分布的基础上设计不同催化试验,研究不同催化时刻(云体发展期、云体成熟期)和三种催化剂量对地面降水、云中水成物浓度、动力场和热力场以及微物理转化过程的影响。模拟试验结果表明:模拟的自然降水分布和实测结果较为一致;不同的催化试验都可以使地面雨量增加,在云体发展期以107个·kg-1剂量进行催化的效果最佳;引入人工冰晶后催化区域水汽和过冷云水含量明显减少、冰晶和雪的含量有所增加、催化区域上升气流明显增强,温度提高;催化后40 min时雪的增长主要依靠其凝华增长、冰晶向雪的自动转化、雪和云滴之间的碰冻以及冰晶和雪之间的碰并;催化后200 min,催化云中各种微物理过程对雪的贡献高于自然云,催化前期消耗了过冷云水,此时云中雪和云滴之间的碰冻对雪的贡献非常微弱,雪的增长主要依靠凝华增长以及雪和冰晶的相互作用。

Source apportionment of atmospheric particulate carbon in Las Vegas,Nevada,USA

研究被进行确定到在在拉斯维加斯山谷的四个城市的地点的碳的 PM2.5 的来源类型的冬贡献，在西南的美国的最快成长的城市的区域之一。24 个小时平均的周围的样品为质量，离子，元素，器官的碳(OC ) ，元素的碳(EC ) ，和踪迹被收集器官的标记分析。另外的大小被做决定日报在轻吸收的黑碳(BC ) 的模式作为为燃烧来源的一个标记。在道路上汽油车辆，在道路上柴油机车辆，和越野的柴油机引擎的碳的下午来源与他们的化学侧面，以及基于燃料的排放因素被描绘，用一个在里面羽毛采样系统。有效变化化学集体平衡(EV-CMB ) 来源分配模型被用于收集的周围的样品，用在象从另外的相关研究的侧面一样的这研究开发的来源侧面。四主要来源在拉斯维加斯山谷以内贡献了 PM2.5 碳：(1 ) 铺了道路灰尘，(2 ) 在道路上汽油车辆，(3 ) 居住木头燃烧，并且(4 ) 在道路上柴油机车辆。CMB 估计在道路上混合了舰队汽油车辆根本是为 OC 和 EC 的最大的来源这些地点。到 OC 和 EC 的铺的道路灰尘的贡献在四个地点是 510% 。在道路上柴油机车辆在城市中心附近在一个地点贡献 22% OC 和 34% EC，它被定位一条主要马路立即顺风。居住木头燃烧比为二个居住邻居地点的在道路上柴油机车辆是更重要的来源。这些结果与我们的概念的模型一致，并且研究方法论可以被用于学习另外的城市的区域。

Surrogate atmospheric dust particles generated from dune soils in laboratory: Comparison with field measurement

Desert dust strongly influences the climate and the environment by altering the radiation budget, participating in atmospheric chemical reactions, and engaging the biogeochemical cycle. Studying its impacts requires knowledge of the physical and chemical properties of the original particles from the source origin. Unfortunately, the field collection of atmospheric samples in the desert is impractical. Fine surface soil is thus considered an alternative material from which to obtain the information applicable to dust particles from the desert soil. In this study, a laboratory system was set up to generate dust particles with simulated natural wind erosion processes from surface soils or directly from desert surfaces. Surface soils and field dust were simultaneously collected during a local blowing dust event. The comparison between the laboratory-generated dust and the field dust showed a consistent trend in particle size distribution and chemical composition. The chemical compositions were found to have explainable differences with the Certified Reference Materials for Asian dust (CJ-2). The laboratory-generated dust particles with the system could be applied as surrogates for soil-emitted dust in desert areas.

Seasonal variations and sources of mass and chemical composition for PM_(10) aerosol in Hangzhou,China

Aerosol observation was conducted for four seasons from September 2001 to August 2002 at five sampling sites in Hangzhou, South China, on PM10 mass, 22 elements (Na, Mg, Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Cd, Ba, and Pb), 5 major ions (F-, Cl-, NO3-, SO42-, and NH4+), and organic and elemental carbon (OC and EC), showing that PM10 mass ranged from 46.7 to 270.8 g/m3, with an annual average of 119.2 g/m3. Na, Al, Si, S, K, Ca, and Fe were the most abundant elements in PM10, most of S being in the form of SO42-. SO42-, NO3-, and NH4+ were the major ions, which contributed to about 20% of the PM10 mass. The mean seasonal concentrations for SO42-, averaged over all sites, were found to be 18.0, 18.5, 24.7, and 21.4 g/m3, for spring, summer, autumn, and winter, respectively, while the corresponding loadings for NO3- were 7.2, 4.7, 7.1, and 11.2 g/m3, and for NH4+ were 6.0, 5.9, 8.2, and 9.3 g/m3, in the form mostly of NH4NO3 in spring, autumn, and winter, and mostly of (NH4)2SO4 in summer. The low NO3-/SO42-ratio found indicates coal combustion as the major source throughout the year. The mean annual concentrations of OC and EC in PM10 were found to be 21.4, and 4.1 g/m3, respectively. Material balance calculation indicated that fugitive dust, the secondary aerosol, and carbonaceous matter were the most abundant species in PM10 for the four seasons, as is characteristic for cities in South China.

MORPHOLOGY AND ELEMENTAL COMPOSITION OF DUSTFALL PARTICLES INSIDE EMPEROR QIN'S TERRA-COTTA WARRIORS AND HORSES MUSEUM

Indoor dustfall samples were collected in Pit 1 and Pit 2 of Emperor Qin’s Terra-cotta Warriors and Horses Museum in Xi’an, Shaanxi Province, China. The morphological and elemental analysis for long-term (>10 years) and short-term (～0.5 year) dustfall particles and lacquer pieces on the faces of partly assembled warriors were performed with scanning electron microscopy with energy dispersive X-ray spectrometer (SEM/EDX). The results showed that the ma-jority of dustfall samples appeared to be composed of mineral dust particles, fly ash, and biological particles with different elemental compositions. Most of the mineral particles had irregular shapes with smooth edges. Small floccules of calcium sulfate were more frequently observed in long-term dustfall samples than in short-term samples, implying a progressive chemical reaction between continuous dustfall particles and atmospheric sulfur dioxide. Crystals of calcium sulfate were also found near pits on both inner and outer surfaces of lacquer pieces, revealing an acid chemical reaction between sulfur dioxide and lacquer material as the cause of the formation of erosion pits and cracks on surface of lacquer pieces.

Improved estimation of PM_(2.5) brown carbon contributions to filter light attenuation

Multiwavelength light attenuation measurements have been acquired as part of thermal/optical carbon analysis in the U.S.Chemical Speciation Network(CSN)and the Interagency Monitoring of PROtected Visual Environments(IMPROVE)network beginning in 2016.These are used to estimate PM_(2.5)brown carbon(BrC)contributions to light absorption at various wavelengths,a useful method for separating biomass burning contributions from other sources.Attenuation of light transmitted through the filter deviates from Beers Law as the mass of light absorbing materials increase.This study estimates the effects of these deviations with empirical adjustment factors applied to samples for CSN from 2016 to 2017 and for IMPROVE from 2016 to 2019.Accounting for the filter loading effect results in an annual average increase of∼6-7%BrC contribution to light attenuation:from 3.6%to 10.7%for the urban,more heavily loaded CSN samples;and from 23.7%to 29.5%for the non-urban IMPROVE samples.An alternative method is examined for BrC and black carbon(BC)adjustments by calculating the AbsorptionÅngström Exponent(AAE)for BC(i.e.,AAE_(BC))based on the ratios of 635 nm/780 nm light attenuation rather than assuming AAE_(BC)of unity.These paired-wavelength calculations result in a median AAE_(BC)of 0.76 for CSN and 0.8 for IMPROVE,with the majority of samples(i.e.,91%of CSN and 70%of IMPROVE)showing AAE_(BC)<1.By assuming negligible contributions from BrC to AAE at longer wavelengths,the amount of light attenuation at shorter wavelengths(e.g.,405 nm)where BrC is dominant can be calculated.The paired-wavelength method applied to the filter loading adjusted data has a greater effect on urban(fresh)than on non-urban(aged)aerosols,resulting in a factor of two increase in annual averaged BrC light attenuation(from 10.7%to 21.6%)for CSN and by a factor of 1.11(from 29.5%to 32.7%)for IMPROVE samples.This result demonstrates the importance of particle loading and AAE correction on quantifying BrC light attenuation from multi-wavelength thermal/optical analysis.

Dilution sampling and analysis of particulate matter in biomass-derived syngas

Thermochemical biomass gasification,followedby conversion of the produced syngas to fuels andelectrical power,is a promising energy alternative.Realworldcharacterization of particulate matter(PM)and othercontaminants in the syngas is important to minimizedamage and ensure efficient operation of the engines itpowers and the fuels created from it.A dilution samplingsystem is demonstrated to quantify PM in syngas generatedfrom two gasification plants utilizing different biomassfeedstocks:a BioMax®15 Biopower System that uses rawand torrefied woodchips as feedstocks,and an integratedbiorefinery(IBR)that uses rice hulls and woodchips asfeedstocks.PM_(2.5)mass concentrations in syngas from theIBR downstream of the purification system were 12.8-13.7μg·m^(-3),which were significantly lower than themaximum level for catalyst protection(500μg·m^(-3))andwere 2-3 orders of magnitude lower than those inBioMax®15 syngas(2247-4835μg·m^(-3)).Ultrafine particlenumber concentration and PM_(2.5)chemical constituentswere also much lower in the IBR syngas than in theBioMax®15.The dilution sampling system enabledreliable measurements over a wide range of concentrations:the use of high sensitivity instruments allowed measurementat very low concentrations(~1μg·m^(-3)),while theflexibility of dilution minimized sampling problems thatare commonly encountered due to high levels of tars in rawsyngas(~1 g·m^(-3)).

Influence of High Relative Humidity on Secondary Organic Carbon: Observations at a Background Site in East China

To investigate the impacts of relative humidity(RH) on secondary organic aerosol(SOA) concentrations and chemical reactions, the carbonaceous aerosol components [i.e., organic carbon(OC) and element carbon(EC)] were quantified in daily PM2.5 samples collected at a background site in East China during summer 2015. Based on the method of EC-tracer, the concentration of secondary organic carbon(SOC) demonstrated an obvious negative relationship with RH higher than 60%. Moreover, the ratio of SOC/EC also exhibited obvious decreasing trends with increasing RH, indicating negative effects for chemical production of SOA under high RH conditions. Due to high RH,photochemistry was weakened, gaseous oxidant concentrations was lowered(e.g., significantly decreased O3 levels),and the production rates of SOA were relatively low. On the other hand, because of more water uptake under higher RH conditions, the aerosol droplet acidity was reduced and enhancement of SOA formation by acidity was accordingly absent. In addition, high RH also plays an important role in changing viscosity of pre-existing aerosol coatings,which can affect reactive uptake yield of SOA. Overall, the results from this study imply that SOA production may be more associated with photochemical processes, while aqueous-phase chemistry is not very important for some SOA formation in a moist ambient environment. In the ambient atmosphere, oxidant concentrations, reaction rates,airborne species, etc., are highly variable. How do these factors affect SOA yields under given ambient environment warrants further detailed investigations.

北京市大气气溶胶中糖类化合物的组成及来源

采用高效阴离子交换色谱-脉冲安培检测(HPAEC-PAD)分析方法,对北京城区PM2.5和PM10中糖类化合物进行定量分析.在北京大气气溶胶中共检出14种糖类化合物,分为脱水糖、糖和糖醇共3大类.脱水糖包括左旋葡聚糖、甘露聚糖和半乳聚糖;糖包括葡萄糖、果糖和海藻糖;糖醇包括阿拉伯糖醇、甘露糖醇、丙三醇、苏糖醇、2-甲基丁四醇(2-甲基苏糖醇和2-甲基赤藓糖醇)、木糖醇和肌醇.脱水糖来源于生物质燃烧,秋冬季节的浓度水平明显高于春夏;而来源于生物源排放的糖和糖醇,冬季浓度水平明显低于其它季节.PMF源解析结果表明,北京大气气溶胶中糖类化合物的来源主要可以分为6类,包括生物质燃烧、异戊二烯SOA、土壤悬浮、真菌孢子、花粉及丙三醇富集源.

PM_(2.5) and PM_(10-2.5) chemical composition and source apportionment near a Hong Kong roadway

Twenty-four-hour PM_(2.5) and PM_(10) samples were collected simultaneously at a highly trafficked roadside site in Hong Kong every sixth day from October 2004 to September 2005.The mass concentrations of PM_(2.5),PM_(10-2.5)(defined as PM_(10)- PM_(2.5)),organic carbon(OC),elemental carbon(EC),water-soluble ions,and up to 25 elements were determined.Investigation of the chemical compositions and potential sources revealed distinct differences between PM_(2.5) and PM_(10-2.5).The annual average mass concentrations were 55.5±25.5 and 25.9±15.7 ug/m^3 for PM_(2.5) and PM_(10-2.5),respectively.EC,OM(OM =OC×1.4),and ammonium sulfate comprised over ~82% of PM_(2.5),accounting for^29%,~27%,and ~25%,respectively,of the PM_(2.5) mass.Low OC/EC ratios(less than 1) for PM_(2.5) suggested that fresh diesel-engine exhaust was a major contributor.Seven sources were resolved for PM_(2.5) by positive matrix factorization(PMF) model,including vehicle emissions(~29%),secondary inorganic aerosols(~27%),waste incinerator/biomass burning(~23%),residual oil combustion(~10%),marine aerosols(~6%),industrial exhaust(~4%),and resuspended road dust(~1%).EC and OM comprised only ~19%of PM_(10-2.5).The average OC/EC ratio of PM_(10-2.5) was 7.8±14.2,suggesting that sources other than vehicular exhaust were important contributors.The sources for PM_(10-2.5) determined by the PMF model included ~20%traffic-generated resuspension(e.g.,tire dust/brake linear/petrol evaporation),~17% locally resuspended road dust,~17% marine aerosols,~12% secondary aerosols/field burning,and ~11%vehicle emissions.

Recent advances for aerosol and environment study in Asia

Rapid economic development over the past two decades in Asian countries such as China and India has raised awareness of pollution control measures necessary to protect public health and welfare.The 7th Asian Aerosol Conference(AAC) of the Asian Aerosol Research Assembly(AARA),was held in Xi'an,China,during August 17-20,2011.The 7th AAC engaged 550 participants from the sciences,industry,and regulatory communities from 21 countries.The conference included～350 plenary,platform,and poster presentations.In this special issue of PARTICUOLOGY,15 peer-reviewed scientific articles have been selected to publish from the conference abstracts to represent recent advances for aerosol and environment study in Asia.