Sources Of Fine Particles Research Articles

Pollution Characteristics and Sources of Fine Particles During a Heavy Haze Episode in Winter: A Case Study of Weinan City

Single Particle Aerosol Mass Spectrometry (SPAMS) is used to investigated a heavy haze process in Weinan,2017. Firstly, the fine particles (PM2.5) using ART-2a was analysed and clustered into 8 classes: organic carbon (OC), organics and elemental carbon combined particles (ECOC), elemental carbon (EC), heavy metal (HM), high molecular organic carbon (HOC), K-rich, levoglucosan (Lev) and dust. Secondly, positive matrix factorization (PMF) was used to identify the sources of PM2.5. Results from PMF showed that the main six sources of PM2.5 were coal-fired (38.48%), secondary (19.19%), biomass burning (15.04%), industry (9.28%), traffic (5.02%), and dust (5.00%). And it is obvious that the major cause of the atmospheric heavy haze is an unfavorable meteorological conditions such as high humidity and low wind speed, as well as coal-fired pollution and secondary pollution caused by heating and industrial production.

Size distribution and chemical composition of primary particles emitted during open biomass burning processes: Impacts on cloud condensation nuclei activation

As a major source of fine particles, open biomass burning can affect climate and the hydrological cycle via the formation of cloud condensation nuclei (CCN) and their deposition. This study investigated the effect of aerosol size and chemical composition (water-soluble compounds, elemental carbon, and organic carbon) on CCN activation during the complete combustion of six commonly used crop (rice, wheat, corn, soybean, and cotton) and leaf residues in a simulation chamber developed for this study. Geometric mean diameters (GMD) of emitted primary particles ranged from 68 to 130 nm and water-soluble compound (WSC) content ranged from 33 to 50%. Although GMDs and WSCs possessed similar temporal tendencies during the combustion process, their average values were dependent on the type of biomass. Number concentration ratios of CCN and particle (CCN/CN) ranged from 1.4–2.1% and 5.8–8.3% at supersaturations of 0.2% and 1.0%, respectively. The CCN/CN value increased during the combustion process when the GMD and WSC content increased. Correlation coefficients for GMD and CCN activation ranged from 0.62 to 0.93, while correlations for WSC and CCN activation ranged from 0.33 to 0.95. Soybean biomass had the highest correlations for both GMD and WSC with CCN activation at various supersaturations. These results suggest that the size and chemical composition of biomass aerosols are important in CCN formation, while the aerosol size has a higher impact.

Is remaining indoors an effective way of reducing exposure to fine particulate matter during biomass burning events?

ABSTRACTBushfires, prescribed burns, and residential wood burning are significant sources of fine particles (aerodynamic diameter <2.5 μm; PM2.5) affecting the health and well-being of many communities. Despite the lack of evidence, a common public health recommendation is to remain indoors, assuming that the home provides a protective barrier against ambient PM2.5. The study aimed to assess to what extent houses provide protection against peak concentrations of outdoor PM2.5 and whether remaining indoors is an effective way of reducing exposure to PM2.5. The effectiveness of this strategy was evaluated by conducting simultaneous week-long indoor and outdoor measurements of PM2.5 at 21 residences in regional areas of Victoria, Australia. During smoke plume events, remaining indoors protected residents from peak outdoor PM2.5 concentrations, but the level of protection was highly variable, ranging from 12% to 76%. Housing stock (e.g., age of the house) and ventilation (e.g., having windows/doors open or closed) played a significant role in the infiltration of outdoor PM2.5 indoors. The results also showed that leaving windows and doors closed once the smoke plume abates trapped PM2.5 indoors and increased indoor exposure to PM2.5. Furthermore, for approximately 50% of households, indoor sources such as cooking activities, smoking, and burning candles or incense contributed significantly to indoor PM2.5.Implications: Smoke from biomass burning sources can significantly impact on communities. Remaining indoors with windows and doors closed is a common recommendation by health authorities to minimize exposures to peak concentrations of fine particles during smoke plume events. Findings from this study have shown that the protection from fine particles in biomass burning smoke is highly variable among houses, with information on housing age and ventilation status providing an approximate assessment on the protection of a house. Leaving windows closed once a smoke plume abates traps particles indoors and increases exposures.

Spatial distribution and temporal trend of airborne trace metal deposition in Albania studied by moss biomonitoring

This study describes the assessment of air quality in Albania using moss biomonitoring. The moss species, Hypnum cupressiforme (Hedw) sps., was used in this study. Mosses were collected during August and September 2015 at 55 sampling sites more or less homogeneously distributed over the entire territory of the country. The spatial distribution and temporal trends of trace metal atmospheric deposition were studied through the determination of twenty inorganic elements, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn. ICP-AES, AAS (As and Cd) and CV AAS (Hg) analysis were used to determine the concentration of the elements. The obtained data show significant differences in the spatial distribution of the elements derived from different emission sources. High emission loads of anthropogenic elements (Cr, Ni, Cu, As and Zn) were detected in the East, and of sea salt elements, particularly Na and K, in the Western coastal line. The distribution trend of the trace metals was studied by comparing the current data with the data of a similar study performed in 2010. Due to the differences in airborne metal concentrations, their scavenging ratios from the atmosphere to the terrestrial ecosystems, and their different uptake-leaching rates during wet and dry deposition respectively of 2015 and 2010 moss grown period, different concentration levels were found in 2010 and 2015 moss metal concentrations. The 2015 moss concentration levels of anthropogenic elements Cr, Ni, Cu, As, Zn and Na had increased, while K, Mg and Hg moss concentration data had declined. Other elements show non significant differences in mosses of both monitoring periods.The contamination levels that were evaluated by calculating the contamination factor (CF) for each element provided similar results for the 2015 and 2010 moss survey. Factor analysis (FA) was applied to identify the possible sources of elements in the 2015 moss samples. Five dominant factors were identified representing long-range and local atmospheric transport of wind-blown soil dust particles (F1); local emission from chromium industry and wind-blown mineral dust particles (F2); anthropogenic sources of traffic emission and wind-blown fine mineral dust particles derived from geogenic origin natural transport from the marine environment (F4); and long-range atmospheric deposition (F5). This study emphasis that moss biomonitoring combined with data analysis and inventory of emission sources are important tools to assess air quality in Albania.

Study of Carbonate Reservoirs Examines Fines Migration in CO2-Saturated-Brine Flow

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 189569, “Fines Migration During CO2-Saturated Brine Flow in Carbonate Reservoirs With Some Migratory Clay Minerals—Malaysian Formations,” by Y. Sazali, Petronas; S. Godeke, SPE, Universiti Brunei Darussalam; W.L. Sazali and J.M. Ibrahim, Petronas; G.M. Graham and S.L. Kidd, Scaled Solutions; and H.A. Ohen, SPE, HPO Global Resources Ventures, prepared for the 2018 SPE International Conference and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, 7–9 February. The paper has not been peer reviewed. A high-carbon-dioxide (CO2) carbonate gas field offshore Sarawak, Malaysia, is scheduled for development. Reservoirs in this region have an average clay content of 8%; more than 50% of this clay content is migratory illite, and 15% is migratory kaolinite. Therefore, fines migration exacerbated by this low-permeability rock becomes a potential production and injection problem. A study was conducted involving rock mineralogy and dynamic flow to evaluate factors contributing to potential fines-migration damage within the production and injection interval. Introduction Migration of fines is associated with oil and gas production in sandstones as well as carbonate reservoirs. Fine particles located on the surface of rock grains are affected by adhesion, drag, and electrostatic and gravitational forces. Drag and lifting forces detach the particle, whereas adhesion, electrostatic, and gravitational forces press the particle to the surface. Generally, the main sources of movable fine particles in sandstone reservoirs are kaolinite and illite clays. Kaolinite particles are flat plates usually stacked in the form of booklets. The surface area of clay minerals, for example, typically is large because of their structure and small size and is more reactive and prone to mobilization and migration. Once mobilized, the fine particles are retained by size exclusion if their size exceeds the pore-throat size of the matrix. Fines damage also occurs when several small fine particles reach a larger pore throat at the same time and compete for passage through the throat with the result of bridging and sedimentation. Usually, in the case of gas/water flow, the fines move with the wetting water phase. However, fines movement taking place before water movement has been observed in a number of gas reservoirs. The in-situ mobilization and migration of fines without a mobile wetting phase is primarily caused by hydrodynamic drag that exceeds the critical rate to mobilize the fines. It has long been realized during corefloods that colloidal controlled release of particles leading to fines migration may be caused by salinity change following flow rate that causes the fines to bridge at the pore throat. Generally, a decrease in salinity or an increased rate of salinity change leads to particle mobilization. This decrease in permeability caused by decreasing salt concentration has been found to be nonmonotonic.

Chemical composition and source apportionment of PM1 and PM2.5 in a national coal chemical industrial base of the Golden Energy Triangle, Northwest China

As part of the Energy Golden Triangle in northwest China and the largest coal-to-liquids industry in the world, the emission and contamination of fine particles in the Ningdong National Energy and Chemical Industrial Base (NECIB) are unknown. There are also large knowledge gaps in the association of air pollution with coal-to-liquids industry. This paper reports the chemical composition and source apportionment of PM1 and PM2.5 collected at two industrial sites Yinglite (YLT) and Baofeng (BF) from a field campaign during summer 2016 and winter 2017. Major chemical components in PM1 and PM2.5, including carbonaceous aerosols, water-soluble inorganic ions, and metal elements were analyzed. The Positive Matrix Factorization (PMF) model and the ISORROPIA II thermodynamic equilibrium model were used to track possible sources and contributions of these chemical components to the formation of the two fine particles. The results identified four primary sources of the fine particles, including vehicle emissions, biomass burning and waste incineration, the secondary aerosols and coal combustion, and soil dust. The PM1 and PM2.5 concentrations were higher in winter than summer. The summed secondary inorganic and carbonaceous aerosols accounted for 36.1–40.0% of PM2.5 mass. The total mass of chemical components identified in the source apportionment only explained about 64.2 to 72.4% of the PM2.5 mass. These results imply some missing sources in this large-scale coal chemical industry base. A coupled weather forecasting and atmospheric chemistry model WRF-Chem was employed to simulate the PM2.5 mass and concentrations of OC and EC, and to examine the origins of PM2.5 across the NECIB. The modeled concentrations of OC and EC were consistent with the sampled data, but the modeled mass of PM2.5 is lower considerably than the measurements, again suggesting unknown sources of fine particles in this energy industrial base.

Vital contribution of residential emissions to atmospheric fine particles (PM2.5) during the severe wintertime pollution episodes in Western China

To mitigate severe wintertime pollution events in Western China, identifying the source of atmospheric fine particles with an aerodynamic diameter of ≤2.5 μm (PM2.5) is a crucial step. In this study, we first analyzed the meteorological and emission factors that caused a considerable increase in the PM2.5 concentration in December 2016. This severe pollution episode was found to be related with unfavorable meteorological conditions and increased residential emissions. The WRF-Chem simulations were used to calculate the residential contribution to PM2.5 through a hybrid source apportionment method. From the validation that used grid data and in situ observations in terms of meteorological elements, PM2.5 and its compounds, the simulated results indicated that the residential sector was the largest single contributor to the PM2.5 concentration (60.2%), because of its predominant contributions to black carbon (BC, 62.1%) and primary organic aerosol (POA, 86.5%), with these two primary components accounting for 70.7% of the PM2.5 mass. Compared with the remote background (RB) region covering the central part of the Tibetan Plateau, the residential sector contributed 11.3% more to PM2.5 in the highly populated mega-city (HM) region, including the Sichuan and Guanzhong Basins, due to greater contribution to the concentrations of primary PM2.5 components. As the main emission source of sulfur dioxide (SO2), nitrogen oxides (NOx), and secondary organic aerosol (SOA), the industrial sector was the second largest contributor to the PM2.5 concentration in the HM region. However, in the RB region, the dominating emissions of NOx, SOA, and BC were from the transport sector; thus, it was the next largest contributor to total PM2.5. An evaluation of the emission control experiment suggested that mitigation strategies that reduce emissions from residential sources can effectively reduce the PM2.5 concentration during heavy pollution periods.

Characteristics of submicron particles coming from a big firecrackers burning event: Implications to atmospheric pollution

Firecrackers burning on different occasions all over the world is a short-term big source of fine particles and their precursors in the air. This study presents the real-time changes in concentrations, composition and characteristics of non-refractory particulate matter smaller than 1 μm aerodynamic diameter (NR-PM1), and black carbon (BC) during the Diwali festival, when a huge amount of firecrackers are burnt in India. Online measurements (1 min integration time) of organics, SO42−, NO3−, NH4+, and Cl− were performed using high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), and that of BC with seven wavelength aethalometer over a big urban city (Ahmedabad, 23.0ºN, 72.6ºE) in western India. A sharp increase (3–23 times higher) in the concentrations of all the measured species was observed on the evening of the Diwali that persisted overnight due to a combination of primary emissions and secondary formation of aerosol. Organics were the dominant contributor (∼85%) followed by SO42− (∼13%), Cl− (∼4%), NO3− (∼4%) and NH4+ (∼2%) to NR-PM1 on the Diwali night. Further, variations in H/C and O/C ratios before, during and after the Diwali suggest fresh emissions of primary organics on the Diwali night, and highly oxidized secondary organic formation on the next day. Aerosol neutralization ratio (ANR, defined as the molar ratio of NH4+ to sum of SO42−, NO3− and Cl−), an indicative of aerosol acidity, reduced to as low as 0.1 on the Diwali night, which has implications to short-term acute atmospheric air pollution.

PM2.5 concentration and composition in the urban air of Nanjing, China: Effects of emission control measures applied during the 2014 Youth Olympic Games

Industrial processes, coal combustion, biomass burning (BB), and vehicular transport are important sources of atmospheric fine particles (PM2.5) and contribute to ambient air concentrations of health-hazardous species, such as heavy metals, polycyclic aromatic hydrocarbons (PAH), and oxygenated-PAHs (OPAH). In China, emission controls have been implemented to improve air quality during large events, like the Youth Olympic Games (YOG) in August 2014 in Nanjing. In this work, six measurement campaigns between January 2014 and August 2015 were undertaken in Nanjing to determine the effects of emission controls and meteorological factors on PM2.5 concentration and composition. PAHs, OPAHs, hopanes, n‑alkanes, heavy metals, and several other inorganic elements were measured. PM2.5 and potassium concentrations were the highest in May–June 2014 indicating the prevalence of BB plumes in Nanjing. Emission controls substantially reduced concentrations of PM2.5 (31%), total PAHs (59%), OPAHs (37%), and most heavy metals (44–89%) during the YOG compared to August 2015. In addition, regional atmospheric transport and meteorological parameters partly explained the observed differences between the campaigns. The most abundant PAHs and OPAHs were benzo[b,k]fluoranthenes, fluoranthene, pyrene, chrysene, 1,8‑naphthalic anhydride, and 9,10‑anthracenedione in all campaigns. Carbon preference index and the contribution of wax n‑alkanes indicated mainly biogenic sources of n‑alkanes in May–June 2014 and anthropogenic sources in the other campaigns. Hopane indexes pointed to vehicular transport as the major source of hopanes, but contribution of coal combustion was detected in winter 2015. The results provide evidence to the local government of the impacts of the air protection regulations. However, differences between individual components were observed, e.g., concentrations of potentially more harmful OPAHs decreased less than concentrations of PAHs. The results suggest that the proportions of hazardous components in the PM2.5 may also change considerably due to emission control measures.

Six sources mainly contributing to the haze episodes and health risk assessment of PM2.5 at Beijing suburb in winter 2016

Aiming to a better understanding sources contributions and regional sources of fine particles, a total of 273 filter samples (159 of PM2.5 and 114 of PM1.0) were collected per 8 h during the winter 2016 at a southwest suburb of Beijing. Chemical compositions, including water soluble ions, organic carbon (OC), and elemental carbon (EC), as well as secondary organic carbon (SOC), were systematically analyzed and estimated. The total ions concentrations (TIC), OC, and SOC of PM2.5 were with the following order: 16:00–24:00 > 08:00–16:00 > 00:00–08:00. Since primary OC and EC were mainly attributed to the residential combustion in the night time, their valley values were observed in the daytime (08:00–16:00). However, the highest ratio value of SOC/OC was observed in the daytime. It is because that SOC is easily formed under sunshine and relatively high temperature in the daytime. Positive matrix factorization (PMF), clustering, and potential source contribution function (PSCF) were employed for apportioning sources contributions and speculating potential sources spatial distributions. The average concentrations of each species and the source contributions to each species were calculated based on the data of species concentrations with an 8 h period simulated by PMF model. Six likely sources, including secondary inorganic aerosols, coal combustion, industrial and traffic emissions, road dust, soil and construction dust, and biomass burning, were contributed to PM2.5 accounting for 29%, 21%, 17%, 16%, 9%, 8%, respectively. The results of cluster analysis indicated that most of air masses were transported from West and Northwest directions to the sampling location during the observation campaign. Several seriously polluted areas that might affect the air quality of Beijing by long-range transport were identified. Most of air masses were transported from Western and Northwestern China. According to the results of PSCF analysis, Western Shandong, Southern Hebei, Northern Henan, Western Inner Mongolia, Northern Shaanxi, and the whole Shanxi provinces should be the key areas of air pollution control in China. The exposure-response function was used to estimate the health impact associated with PM2.5 pollution. The population affected by PM2.5 during haze episodes reached 0.31 million, the premature death cases associated with PM2.5 reached 2032. These results provided important implication for making environmental policies to improve air quality in China.

Characterizing the Level and Distribution of Wildland Fire Smoke Impacts in the U.S. among Susceptible Populations

Wildland fires are a significant source of fine particles (PM2.5) in the atmosphere. Previous research has explored the air quality and human health impacts of wildland fire events over a multi-year period in the United States. Less well understood is how wildland fires affect populations most susceptible and vulnerable to poor air quality. In this analysis, we characterize the wildland fire-attributable exposure and PM2.5 related mortality and morbidity impacts among several subpopulations between 2008 and 2012. Following approaches previously employed in the literature, we operationalize the terms susceptible and vulnerable according to a variety of attributes that can be observed at the population-level; these include age, race, ethnicity and baseline rate of mortality and morbidity. We also draw from approaches used within the Environmental Justice literature&amp;#8212;the Gini Coefficient and Atkinson Index in particular&amp;#8212;to quantify the level of mortality and morbidity risk inequality within susceptible and vulnerable groups and between these groups and the rest of the population affected by wildland smoke. We explore the extent to which the extent and intensity of wildland fire events are associated with greater or lesser risk inequality among these subgroups over this five-year period.

Fine Particle Sources and Cognitive Function in An Older Puerto Rican Cohort in Greater Boston.

Puerto Ricans living in the mainland US have substantially higher rates of impairment to cognitive performance as compared to non-Hispanic Whites, with air pollutant exposures a potential risk factor. We investigated whether exposures to specific air pollution sources were associated with performance across several cognitive domains in a cohort of Puerto Rican older adults. To investigate the association between sources of PM2.5 and cognitive performance in each of five cognitive domains. We obtained demographic, health, and cognitive function data for 1500 elderly participants of the Boston Puerto Rican Health Study (BPRHS). Cognitive function was assessed in each of two waves for five domains: verbal memory, recognition, mental processing, and executive and visuospatial function. To these data, we linked concentrations of fine particulate matter (PM2.5) and its components, black carbon (BC), nickel, sulfur, and silicon, as tracers for PM2.5 from traffic, oil combustion, coal combustion, and resuspended dust, respectively. Associations between each PM2.5 component and cognitive domain were examined using linear mixed models. One year moving average exposures to BC were significantly associated with decreased verbal memory (-0.38;95% CI: -0.46,-0.30), recognition (-0.35; 95% CI: -0.46,-0.25), mental processing (-1.14; 95% CI: -1.55,-0.74), and executive function (-0.94; 95% CI: -1.31,-0.56). Similar associations were found for nickel. Associations for sulfur, and silicon, and PM2.5 were generally null, although sulfur (-0.51; 95% CI -0.75,-0.28) silicon (-0.25; 95% CI: -0.36,-0.13) and PM2.5 (-0.35; 95% CI: -0.57,-0.12) were associated with decreased recognition. Long-term exposures to BC and nickel, tracers of traffic and oil combustion, respectively, were associated with decreased cognitive function across all domains, except visuospatial function.

Analysis of Chemical Composition of the Fine Particulate Matter in Summer in Tianjin City via a Single Particle Aerosol Mass Spectrometer (SPAMS)

As an important megacity of the Beijing-Tianjin-Hebei air pollution transmission channel and the Bohai Sea Economic Zone, Tianjin is influenced by air pollution in recent years, thus research on the fine particulate matter in Tianjin is of vital value. In this study, single particle aerosol mass spectrometry (SPAMS) was used to measure data of Jinnan District in Tianjin during August 2017, to describe the chemical features of fine particles in summer ambient air and estimate the potential pollution sources of fine particles. By using the ART-2a clustering method, 12 classes of PM were acquired, such as elemental carbon particles, Fe-NO3 particles, Na-K particles, and metal particles. After monitoring the size distribution and diurnal variation of fine particles, it was concluded that the ratio of EC particles decreased as the size increased, whereas dust particles and Fe-NO3 particles showed the opposite trend; three types of EC particles varied differently in a day according to the photochemical reaction; and the ratio of Fe-NO3 particles was elevated in the daytime because of industrial production during that period. Backward trajectories of daily airflow at the measured spot were also calculated. When the monitoring site was affected by the air mass from the southwest, coal-burning particles may have contributed more; whereas, when the air mass from the southeast occurred more frequently, biomass burning and sea salt particles possibly contributed more.

Influence of advanced wood-fired appliances for residential heating on indoor air quality

This work was aimed at studying particulate matter (PM) in the indoor atmosphere of two flats where airtight biomass systems were used for domestic heating. PM10 and PM2.5 samples were collected by means of nine parallel sampling units, located in the outdoor and indoor areas of each flat. The samples were analyzed for PM macro-components (organic carbon, elemental carbon, macro-elements and inorganic ions) and for the soluble and residual fractions of micro-elements; the influence of the main PM sources on the indoor air quality was evaluated.The results confirm that infiltration from outdoor represents the main source of fine particles, while dust re-suspension, enhanced by the movements of the inhabitants, is one of the most important sources of coarse particles. Biomass-fueled heating systems are a significant source of indoor pollution, mainly due to the cleaning operations required for the removal of residual ash, which release particles in both the fine and the coarse size range. The impact of these operations resulted in indoor to outdoor ratios higher than one for most of the considered PM components. Very high amounts of copper and manganese, elements likely involved in the generation of oxidative stress, were released into the environment during ash removal from the pellet stove. Although this operation was very limited in time (about 15 min), the average concentration of Cu and Mn in PM10 and PM2.5 during the study period (18 days) was more than six times (Cu) and about twice (Mn) the concentration values measured outdoors.

Effects of urban wastewater on hyporheic habitat and invertebrates in Mediterranean streams

Wastewater discharges into fluvial ecosystems represent a significant and continuous source of fine particles and nutrients that can severely modify stream community composition and functionality. Depending on both wastewater and stream features (e.g., nutrient removal treatments and stream dilution capacity), the ecological effects can be more or less severe. To determine how hyporheic habitat and hyporheos are affected, we analysed eight Mediterranean streams both upstream and downstream of a wastewater effluent. The results demonstrated that environmental factors associated with clogging, such as the quantity of fine particulate and organic matter in sediment, were magnified downstream of the wastewater inputs. Likewise, dissolved nutrients also increased but depended to a greater extent on the presence of a wastewater treatment plant and on the nitrogen and phosphorus removal treatments. The hyporheic invertebrates were more affected by clogging than by eutrophication. Both richness and diversity parameters were negatively correlated with clogging features but were not correlated with eutrophication. The most affected taxa were Macrocrustaceans, Hydrachnidia and several insect species, which decreased or were not detected downstream of the effluents. On the contrary, other taxa such as Naididae (Oligochaeta), Orthocladiinae (Chironomidae) and Potamopyrgus antipodarum (Gastropoda) benefited from the wastewater inputs.

Time-resolved chemical composition of small-scale batch combustion emissions from various wood species

Small-scale batch combustion of wood is a major source of fine particles, black carbon emission and polycyclic aromatic hydrocarbons in Finland. The mass and chemical compositions of batch combustion emissions are known to be highly time-dependent. In this study, the gaseous and particulate batch combustion emissions of three European wood species (beech, birch and spruce) were quantified in detail with an extensive set of online analysers, including a soot particle aerosol mass spectrometer (SP-AMS) for real-time detection of particulate chemical composition. Ignition and a new batch addition on top of glowing embers were identified as the primary low temperature events during which both particulate and gaseous organic emissions peaked. The flaming combustion created high temperature conditions and produced increased emissions of refractory black carbon (rBC) and PAHs. The residual char combustion phase was characterized by low particulate mass emission consisting mainly of alkali salts and elevated concentrations of gaseous organic emissions and CO. Overall, hardwood species (beech and birch) had the highest PM1 emissions, and the difference between the lowest average emission (spruce) and the highest (birch) was more than 3-fold. The increasing combustion chamber temperature during sequential combustion of wood batches was found to decrease the carbonaceous fraction of the PM as well as OC/EC ratio, as the result of more efficient secondary combustion.

Evolution in physiochemical and cloud condensation nuclei activation properties of crop residue burning particles during photochemical aging.

As a main form of biomass burning in agricultural countries, crop residue burning is a significant source of atmospheric fine particles. In this study, the aging of particles emitted from the burning of four major crop residues in China was investigated in a smog chamber. The particle size distribution, chemical composition and cloud condensation nuclei (CCN) activity were simultaneously measured. The properties of crop residue burning particles varied substantially among different fuel types. During aging, the particle size and mass concentration increased substantially, suggesting condensational growth by formation of secondary aerosols. The particle composition was dominated by organics. Aging resulted in considerable enhancement of organics and inorganics, with enhancement ratios of 1.24-1.44 and 1.33-1.76 respectively, as well as a continuous increase in the oxidation level of organics. Elevated CCN activity was observed during aging, with the hygroscopicity parameter κ varying from 0.16 to 0.34 for fresh particles and 0.19 to 0.40 for aged particles. Based on the volume mixing rule, the hygroscopicity parameter of organic components (κorg) was derived. κorg exhibited an increasing tendency with aging, which was generally consistent with the tendency of the O:C ratio, indicating that the oxidation level was related to the hygroscopicity and CCN activity of organic aerosols from crop residue burning. Our results indicated that photochemical aging could significantly impact the CCN activation of crop burning aerosols, not only by the production of secondary aerosols, but also by enhancing the hygroscopicity of organic components, thereby contributing to the aerosol indirect climate forcing.

Estimation of Fine Particle (PM2.5) Emission Inventory from Cooking: Case Study for Shanghai

Cooking is one of important emission sources of fine particles (PM2.5). This study using the catering enterprises of Shanghai as an example, presents a method to estimate the PM2.5 emission inventory from cooking according to the number of stoves, cooking time, and number of customers. Based on in situ measurements, the concentrations of PM2.5 emissions ranged from 0.1 mg ·m-3 to 1.8 mg ·m-3, which exceeded the limit (1.0 mg ·m-3 for lampblack) in the national standard. Organic carbon dominated the PM2.5 emitted from cooking, accounting for more than 50%. Extremely high ratios of organic carbon to elemental carbon were observed, ranging from 58.8 to 752.3, which could be used as an indicator of cooking emissions. The emission factors of PM2.5 in the catering industry are closely related to the scale of the catering enterprises. The emission factors of large-and medium-sized enterprises are obviously higher than those of small and micro enterprises. The PM2.5 emissions of catering enterprises are mainly attributed to high emission loads of large enterprises and those for a large number of small and medium enterprises. The PM2.5 emission inventory of cooking in Shanghai was calculated according to the three emission factors above, and the results were very close. Therefore, the method for estimating the PM2.5 emission inventory for cooking presented in this study is helpful for other Chinese cities to calculate their PM2.5 emission inventory from cooking.

Analysis of the Composition of Atmospheric Fine Particles (PM2.5) Produced by Burning Fireworks

Burning fireworks is one of the sources of atmospheric fine particles (PM2.5). The Chinese Spring Festival in Quanzhou City was taken as an example to study the effects of burning fireworks on the occurrence of PM2.5, and provide information on protection against air pollution caused by special pollution sources. The results showed that the concentrations of SO2, PM10, and PM2.5 increased appreciably, and the concentration of PM2.5 increased most significantly during the fireworks burning period. The peak daily average concentration in the urban area was about 4 times the annual average concentration in the urban area. The peak value of the hourly average concentration of PM2.5 in the Tushan Street station was about 21 times the annual average concentration in the urban area. At the peak of the discharge, the ratios of the characteristic elements of fireworks, such as Al, Mg, Ba, Cu, and Sr, increased rapidly, and the hourly number concentrations of Al+, Mg+, Ba+, and Cu+ were highly correlated. During the monitoring period, the main pollution sources of fine particles in Quanzhou City were fireworks and biomass burning, which accounted for more than half of the total particulate matter. The proportion of pollutants originating from coal-based and industrial process sources were relatively low, and both of them accounted for less than 10.0% of the particulate matter. The concentration of PM2.5 was up to 0.578 mg·m-3 during the fireworks burning period, the rate of contribution by fireworks increased to 58.2%. Analysis of the pollution process showed that the changes in the concentration of PM2.5 have a similar trend with the number concentration and the ratio of fireworks burning. The results indicated that the main reason of the deterioration of the atmospheric environment during the Chinese Spring Festival in Quanzhou is the centralized discharging of fireworks.

Quantifying daily contributions of source regions to PM concentrations in Marseille based on the trails of incoming air masses

The hourly trails (trajectory points) of incoming air masses have been used in this study in order to compose independent variables for the quantification of regional PM10 and PM2.5 contributions in Marseille (Southern France), and also for the estimation of the atmospheric dispersion effect. These prediction variables were used as input for a Multiple Linear Regression Model (MLRM) in order to estimate daily PM10 and PM2.5 concentrations in Marseille. For a more exact localization of fine and coarse particle sources, during cold and warm period, our analysis was supplemented by the findings of Concentration Weighted Trajectory (CWT) algorithm on a 0.5°·0.5° resolution grid. A strong coherence was revealed among measured and estimated daily levels of PM10 and PM2.5; thus, the proposed MLRM can be a useful tool for assessing air quality in terms of atmospheric circulation. Increased PM contributions in Marseille from local and all-around emission sources were indicated by MLRM primarily within cold seasons. In addition, Northeast (NE) atmospheric circulation was associated by MLRM and CWT with extreme intrusions of exogenous particulate air pollution from Central Europe, during winter and early spring. Throughout warm period, the scarceness of NE airflows prevented the transportation of aerosols from continental Europe. Episodes of desert dust transportation from Northwest Africa (Algeria and Tunisia) had a clear footprint in the PMCOARSE (=PM10-PM2.5) fraction.