Main Sources Of Particulate Matter Research Articles

Source apportionment study on particulate air pollution in two high-altitude Bolivian cities: La Paz and El Alto

Abstract. La Paz and El Alto are two fast-growing, high-altitude Bolivian cities forming the second-largest metropolitan area in the country. Located between 3200 and 4050 m a.s.l. (above sea level), these cities are home to a burgeoning population of approximately 1.8 million residents. The air quality in this conurbation is heavily influenced by urbanization; however, there are no comprehensive studies evaluating the sources of air pollution and their health impacts. Despite their proximity, the substantial variation in altitude, topography, and socioeconomic activities between La Paz and El Alto result in distinct sources, dynamics, and transport of particulate matter (PM). In this investigation, PM10 samples were collected at two urban background stations located in La Paz and El Alto between April 2016 and June 2017. The samples were later analyzed for a wide range of chemical species including numerous source tracers (OC, EC, water-soluble ions, sugar anhydrides, sugar alcohols, trace metals, and molecular organic species). The United States Environmental Protection Agency (U.S. EPA) Positive Matrix Factorization (PMF v.5.0) receptor model was employed for the source apportionment of PM10. This is one of the first source apportionment studies in South America that incorporates an extensive suite of organic markers, including levoglucosan, polycyclic aromatic hydrocarbons (PAHs), hopanes, and alkanes, alongside inorganic species. The multisite PMF resolved 11 main sources of PM. The largest annual contribution to PM10 came from the following two major sources: the ensemble of the four vehicular emissions sources (exhaust and non-exhaust), accountable for 35 % and 25 % of the measured PM in La Paz and El Alto, respectively; and dust, which contributed 20 % and 32 % to the total PM mass. Secondary aerosols accounted for 22 % (24 %) in La Paz (El Alto). Agricultural smoke resulting from biomass burning in the Bolivian lowlands and neighboring countries contributed to 9 % (8 %) of the total PM10 mass annually, increasing to 17 % (13 %) between August–October. Primary biogenic emissions were responsible for 13 % (7 %) of the measured PM10 mass. Additionally, a profile associated with open waste burning occurring from May to August was identified. Although this source contributed only to 2 % (5 %) of the total PM10 mass, it constitutes the second largest source of PAHs, which are compounds potentially hazardous to human health. Our analysis additionally resolved two different traffic-related factors, a lubricant source (not frequently identified), and a non-exhaust emissions source. Overall, this study demonstrates that PM10 concentrations in La Paz and El Alto region are predominantly influenced by a limited number of local sources. In conclusion, to improve air quality in both cities, efforts should primarily focus on addressing dust, traffic emissions, open waste burning, and biomass burning.

Air phyto-cleaning by an urban meadow – Filling the winter gap

Urban areas are characterised by polluted air which endangers the health and quality of life of city dwellers. Among the dangerous air contaminants is particulate matter (PM) and one of the main sources of PM in urban areas is road traffic. Studies have already shown that the air can be phyto-cleaned by plants, especially trees and shrubs. However, for safety reasons, planting trees and shrubs in some places is problematic, e.g. close to roads. These locations are usually occupied by lawns, which are plant communities of low ecological value. Unfortunately, too little attention has been paid so far to urban meadows. Therefore, this study (i) investigated for the first time the phyto-cleaning potential of an urban meadow all year round, including autumn–winter period, and (ii) compared the efficiency and mechanisms of PM phyto-cleaning by an urban meadow and lawn during the vegetative season. Plant material was harvested from urban meadow (in June, August, November and March) and lawns (in June and August) located by a busy road in Warsaw (Poland). PM was analysed in two categories (surface PM and in-wax PM) and two size fractions (fine: 0.2–2.5 µm, coarse: 2.5–10 µm). The results obtained suggested that accumulation of PM by urban meadow is possible even out of vegetative season. In autumn and winter, even though the meadow plants were physiologically not active, they still participated in air phyto-cleaning. Urban meadow phyto-cleaned air most effectively in summer when the vegetation was fully developed, and least effectively in autumn. During the vegetative season, the urban meadow accumulated more PM than lawns, mostly due to the greater height and complex structure. Therefore, urban meadow would appear to offer an promising solution to problem of phyto-cleaning of urban air in the immediate vicinity of roads throughout the year.

Cooking Particulate Matter: A Systematic Review on Nanoparticle Exposure in the Indoor Cooking Environment

Background: Cooking and fuel combustion in the indoor environment are major sources of respirable suspended particulate matter (RSPM), which is an excellent carrier of potentially harmful absorbed inorganic and organic compounds. Chronic exposure to RSPM can lead to acute pulmonary illness, asthma, cardiovascular disease, and lung cancer in people involved in cooking. Despite this, questions remain about the harmfulness of different particulate matter (PM) sources generated during cooking, and the factors influencing PM physico-chemical properties. The most reliable methods for sampling and analyzing cooking emissions remain only partially understood. Objectives: This review aims to comprehensively assess the risks of PM generated during cooking, considering the main sources of PM, PM chemical composition, and strategies for PM physico-chemical analysis. We present the first systematic analysis of PM sources and chemical composition related to cooking. We highlight significant differences between studies using different experimental conditions, with a lack of a standard methodology. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement rules and the Patient, Intervention, Comparison, and Outcome (PICO) strategy for scientific research, three different scientific databases (PubMed, Scopus, and Web of Science) were screened to find scientific articles that measure, collect, and analyze the chemical composition of nanometer- and micrometer-sized PM generated during cooking activities under different conditions. Data are summarized to assess risk, evaluating the main sources and factors influencing PM generation, their chemical composition, and how they have been collected and analyzed in changing experimental conditions. Results: From 2474 search results, there were 55 studies that met our criteria. Overall, the main variable sources of PM in cooking activities relate to the stove and fuel type. The concentration and chemical–physical properties of PM are also strongly influenced by the food and food additive type, food processing type, cooking duration, temperature, and utensils. The most important factor influencing indoor PM concentration is ventilation. The PM generated during cooking activities is composed mainly of elemental carbon (EC) and its derivatives, and the porous structure of PM with high surface-to-volume ratio is a perfect carrier of inorganic and organic matter. Conclusions: This review reveals a growing interest in PM exposure during cooking activities and highlights significant variability in the chemical–physical properties of particles, and thus variable exposure risks. Precise risk characterization improves possible preventive strategies to reduce the risk of indoor pollutant exposure. However, comprehensive PM analysis needs proper sampling and analysis methods which consider all factors influencing the physico-chemical properties of PM in an additive and synergistic way. Our analysis highlights the need for method standardization in PM environmental analyses, to ensure accuracy and allow deeper comparisons between future studies.

Rainfall characteristics significantly affect the scavenging of water-soluble ions attached to leaves

Precipitation is considered the most effective way to remove particulate matter from the leaves of plants. Changes in rainfall characteristics can affect the scavenging processes of particulate matter from leaves. In order to better understand the dynamics of PM scavenging during rainfall, especially the water-soluble ions components, leaves from the 11 plant species (trees, shrubs, terrestrial herbs, wetland plants) from the Olympic park were sampled and used in indoor experiments. During the experiments, the rainfall intensity was set at 30 mm/h, 45 mm/h, and 60 mm/h, and the duration was divided into 0–20 min, 20–40 min, and 40–60 min. The sampled plant leaves were set in the experiments at 1 m and 3 m height from the ground. Concentrations and compositions of nine water-soluble ions of rainfall samples were analyzed in this experiment. The results revealed that SO42-, Ca2+, and Na+ were the most abundant ionic species removed from the leaves, and NO3- ranked fourth, followed by Cl-, Mg2+ K+, NH4+, and F-. The ions concentration of rainfall samples decreased when the rain intensity increased from 30 to 45 mm/h and when the rain intensity increased to 60 mm/h. The efficiency of scavenging during different rainfall durations depends on the ionic species. Na+, Mg2+, Ca2+, and SO42- concentrations increased with the increase in rainfall duration, whereas those of NH4+, K+, and Cl- decreased. The effect of leaf height on ions concentration of rainfall samples was also different among the ionic species: Na+, Mg2+, Ca2+, NO3-, and F- concentrations were significantly higher at 1 m compared with 3 m. The principal component analysis of ions in rainfall samples revealed two main sources of particulate matter in our study. One is from vehicle exhaust and industrial and agricultural pollution. The other is agricultural combustion and ground dust sources. The results of the above study can provide a basis and theoretical support for the establishment of urban cleaning systems and the prevention of air pollution.

Winter and spring variation in sources, chemical components and toxicological responses of urban air particulate matter samples in Guangzhou, China

The sources and chemical components of urban air particles exhibit seasonal variations that may affect their hazardousness to human health. Our aims were to investigate winter and spring variation in particulate matter (PM) sources, components and toxicological responses of different PM size fractions from samples collected in Guangzhou, China. Four size-segregated PM samples (PM10–2.5, PM2.5–1, PM1–0.2, and PM0.2) were collected separately during winter (December 2017 and January 2018) and spring (March 2018). All PM samples were analyzed for chemical components and characterized by source. RAW 264.7 macrophages were exposed to four doses of PM samples for 24 h. Cytotoxicity, oxidation, cell cycle, genotoxicity and inflammatory parameters were tested. PM concentrations were higher in the winter samples and caused more severe cytotoxicity and oxidative damage than to PM in the spring samples. PM in winter and spring led to increases in cell cycle and genotoxicity. The trends of size-segregated PM components were consistent in winter and spring samples. Metallic elements and PAHs were found in the largest concentrations in winter PM, but ions were found in the largest concentrations in spring PM. metallic elements, PAHs and ions in size-segregated PM samples were associated with most toxicological endpoints. Soil dust and biomass burning were the main sources of PM in winter, whereas traffic exhaust and biomass burning was the main source with of spring PM. Our results suggest that the composition of PM samples from Guangzhou differed during winter and spring, which led to strong variations in toxicological responses. The results demonstrate the importance of examining a different particle sizes, compositions and sources across different seasons, for human risk assessment.

Size-Segregated Particulate Matter Down to PM0.1 and Carbon Content during the Rainy and Dry Seasons in Sumatra Island, Indonesia

Size-segregated particulate matter (PM) including the PM0.1 fraction, particles ≤0.1 µm, was monitored during the rainy and dry seasons at three different cities in Sumatra island, Indonesia in 2018. In order to identify possible emission sources, carbonaceous components in the particles collected by a cascade air sampler that is capable of collecting PM0.1 particles were analyzed by applying a thermal/optical reflectance (IMPROVE-TOR) protocol. The PM0.1 levels in the Jambi and Pekanbaru areas were similar to those in large cities in East Asia, such as Bangkok and Hanoi. During the rainy season, local emissions in the form of vehicle combustion were the main sources of PM. The influence of peatland fires in the dry season was more significant in cities that are located on the east coast of Sumatra island because of the larger number of hotspots and air mass trajectories along the coast. A clear increase in the carbonaceous profiles as OC, TC, and OC/EC ratios in the dry season from the rainy season was observed, particularly in fine fractions such as PM0.5–1. In both seasons, EC vs. OC/EC correlations and soot-EC/TC ratios showed that the PM0.1 fraction in Sumatra island was heavily influenced by vehicle emissions, while the effect of biomass burning was more sensitive with respect to the PM0.5–1 fraction, particularly in Jambi and Pekanbaru sites during the dry season.

Comparison of PM10 Sources at Traffic and Urban Background Sites Based on Elemental, Chemical and Isotopic Composition: Case Study from Krakow, Southern Poland

In large urban agglomerations, car traffic is one of the main sources of particulate matter. It consists of particulate matter directly generated in the process of incomplete liquid fuel burning in vehicle engine, secondary aerosols formed from exhaust gaseous pollutants (NOx, SO2) as well as products of tires, brake pads and pavement abrasion. Krakow is one of the cities in Europe with the highest concentrations of particulate matter. The article presents the results of combined elemental, chemical and isotopic analyses of particulate matter PM10 at two contrasting urban environments during winter and summer seasons. Daily PM10 samples were collected during the summer and winter seasons of 2018/2019 at two stations belonging to the network monitoring air quality in the city. Mean PM10 concentrations at traffic-dominated stations were equal to 35 ± 7 µg/m3 and 76 ± 28 µg/m3 in summer and winter, respectively, to be compared with 25.6 ± 5.7 µg/m3 and 51 ± 25 µg/m3 in summer and winter, respectively, recorded at the urban background station. The source attribution of analyzed PM10 samples was carried out using two modeling approaches: (i) The Positive Matrix Factorization (PMF) method for elemental and chemical composition (concentrations of elements, ions, as well as organic and elemental carbon in daily PM10 samples), and (ii) Isotope Mass Balance (IMB) for 13C and 14C carbon isotope composition of carbonaceous fraction of PM10. For PMF application, five sources of particulate matter were identified for each station: fossil fuel combustion, secondary inorganic aerosols, traffic exhaust, soil, and the fifth source which included road dust, industry, construction work. The IMB method allowed the partitioning of the total carbon reservoir of PM10 into carbon originating from coal combustion, from biogenic sources (natural emissions and biomass burning) and from traffic. Both apportionment methods were applied together for the first time in the Krakow agglomeration and they gave consistent results.

Kretek Cigarettes and Particulate Matter Emissions—An Aerosol Spectrometric Study on Typical Indonesian Brands Flavored With Cloves

Abstract Introduction In Indonesia, smoking is widespread. The same applies to second-hand smoke (SHS) exposure. More than 90% of Indonesian smokers smoke clove cigarettes, so-called Kreteks. They often contain more tar and nicotine than conventional cigarettes, but little is known about particulate matter (PM) emissions. In smokers’ homes, SHS is the main source of PM that is hazardous to health. This study presents data of PM emissions from Kreteks. Methods SHS was generated in a closed 2.88 m³ measuring chamber. PM fractions (PM10, PM2.5, PM1) of three popular Kretek brands (two king-sized and one slim-sized) in comparison to conventional cigarettes and a reference cigarette were measured by laser aerosol spectroscopy in real-time. Results The king-sized Kreteks reached PM10 and PM2.5 mean concentrations of up to about 3000 µg/m³, and PM1 mean concentrations of up to about 2700 µg/m³. Consequently, these Kreteks emitted up to about 100% more PM10 and PM2.5, respectively 84% more PM1 than the reference cigarette, and up to about 260% more PM10 and PM2.5, respectively 234% more PM1 than the other investigated cigarettes. Conclusions PM emissions from Kreteks can be very high. The Indonesian public should be informed and warned about it, considering the high prevalence of smoking and SHS exposure, in particular. The Indonesian tobacco control regulation is limited, and it is overdue to start with a serious and effective tobacco control policy. PM declaration to government authorities could be useful in smoking prevention and tobacco control. Implications Research data are limited for Kretek cigarettes, including data on particulate matter (PM). The clove buds in Kretek cigarettes are for flavoring the smoke and shall soften the smoke feeling. That makes them very popular in Indonesia, in particular. The declaration of PM data of Kreteks and other tobacco products can play a key role in a more effective tobacco policy to reduce consumption of tobacco products, not only in Indonesia. To provide data on PM emissions, this study ascertained PM amounts in passive smoke from Indonesian Kreteks.

Particulate emissions of real-world light-duty gasoline vehicle fleet in Iran

Fine particulate matter cause profound adverse health effects in Iran. Road traffic is one of the main sources of particulate matter (PM) in urban areas, and has a large contribution in PM2.5 and organic carbon concentration, in Tehran, Iran. The composition of fine PM vehicle emission is poorly known, so this paper aims to determine the mixed fleet source profile by using the analysed data from the two internal stations and the emission factor for PM light-duty vehicles emission. Tunnels are ideal media for extraction vehicle source profile and emission factor, due to vehicles are the only source of pollutant in the urban tunnels. In this study, PM samples were collected simultaneously in two road tunnel stations and at a background site in Niyayesh tunnel in Tehran, Iran. The tunnel samples show a large contribution for some elements and ions, such as Fe (0.23 μg μg−1 OC), Al (0.02 μg μg−1 OC), Ca (0.055 μg μg−1 OC), SO4 (0.047 μg μg−1 OC), Docosane (0.0017 μg μg−1 OC), Triacontane (0.016 μg μg−1 OC), Anthracenedione (0.0003 μg μg−1 OC) and Benzo-perylene (0.0002 μg μg−1 OC). In overall, on-road gasoline vehicle fleets source profile extracted in this study is similar to composite profiles derived from roadside tunnel measurment performed in other countries during the last decades. The PM2.5 emission factor for Tehran's light-duty vehicle fleet has been extracted 16.23 mg km−1. vehicle−1and 0.09 g kg−1. The profile would be used for Chemical Mass Balance Model studies for Iran and other countries with a similar road traffic fleet mix. Also, it would be very suitable for use in emission inventories improvement. The results of this study can be used for choosing the best management strategies and provide comperhensive insight to fine PM traffic emission in Tehran.

Seasonal occurrence, source apportionment, and cancer risk assessment of PAHs in the second largest international holy metropolitan: Mashhad, Iran.

Street dust resuspension is one of the main sources of particulate matter with impacts on air quality, health, and climate. This research was aimed to determine the concentration, source, and health risk of polycyclic aromatic hydrocarbons (PAHs) in street dust of Mashhad city. To this end, USEPA-regulated 16 PAHs were measured in 84 dust samples using gas chromatography coupled to mass spectrometry (GC-MS). The source of Σ16PAHs was identified using diagnostic ratios (DRs), positive matrix factorization (PMF), and principal component analysis (PCA). The measured Σ16PAHs demonstrated different spatial concentrations (from 1,005 to 9,138.96 μg kg-1) and showed higher levels in summer (1,206.21-9,138.96 μg kg-1), although 4-ring PAHs exhibited maximum levels in both summer and winter. The findings revealed that the dust-deposited PAHs are predominantly emitted through combustion of fossil fuels (such as diesel and gasoline) and natural gas. The total incremental lifetime cancer risk (ILCR) was assessed by considering three possible exposure routes separately for children and adults and calculated carcinogenic risk values of 2.24E-06 and 2.14E-06, respectively. ILCR is above the baseline value (1.0E-06) for children and adults in both seasons.

Source apportionment and health risk due to PM10 and TSP at the surface workings of an underground coal mine in the arid desert region of northwestern China

The surface operations area of an underground coal mine near Lingwu in Ningxia Hui Autonomous Region was selected for this study. Particulate matter (PM) was sampled in the coal screening plant during the day and night in Spring and Winter, 2019. Twelve trace metals and eight water-soluble ions in particulate matter up to 10 μm in diameter (PM10) and total suspended particles (TSP) were analyzed using ICP-OES and ion chromatography, respectively. The enrichment factor (EF) and positive matrix fraction (PMF) were used to identify potential sources of particulate metals. The forward trajectory model was used to analyze the main migration pathways of particles. Results showed that higher concentrations of PM10 and TSP were found in Spring than in Winter; the concentration of PM at night was lower than during the day. Most of the trace metals in TSP were greater than in PM10, while the content of most water-soluble ions in TSP was lower than in PM10. The EF analysis confirmed that particulate metals were attributable to anthropogenic emission. PMF model results further demonstrated that the main sources of PM in both seasons were regional suspended dust, traffic emission, industrial emission and coal burning. Air mass dispersion analysis showed that PM generated by these operations may spread to eastern and southeastern China within 72 h in Spring, while mainly to southeastern and southern China in Winter. These suggest a need for greater focus on strengthening the monitoring and early warning of the presence of atmospheric PM in southern Shanxi, China. Because of the risks that particulate metals pose to human health, the protection of children should be strengthened around the surface operation area of an underground coal mine. Moreover, monitoring of the concentrations of Cr in PM10 and Mn in TSP in Spring should be strengthened, and the opposite procedure should be adopted in Winter. These findings are useful for providing a theoretical basis for the prevention and control of pollutants in underground mining areas and the construction of cleaner production lines.

Spatial Distribution and Chemical Composition of Road Dust in Two High-Altitude Latin American Cities

Road dust (RD) resuspension is one of the main sources of particulate matter in cities with adverse impacts on air quality, health, and climate. Studies on the variability of the deposited PM10 fraction of RD (RD10) have been limited in Latin America, whereby our understanding of the central factors that control this pollutant remains incomplete. In this study, forty-one RD10 samples were collected in two Andean cities (Bogotá and Manizales) and analyzed for ions, minerals, and trace elements. RD10 levels varied between 1.8–45.7 mg/m2, with an average of 11.8 mg/m2, in Bogotá and between 0.8–26.7 mg/m2, with an average of 5.7 mg/m2, in Manizales. Minerals were the most abundant species in both cities, with a fraction significantly larger in Manizales (38%) than Bogotá (9%). The difference could be explained mainly by the complex topography and the composition of soil derived from volcanic ash in Manizales. The volcanic activity was also associated with SO4−2 and Cl−. Enrichment factors and principal component analysis were conducted to explore potential factors associated to sources of RD10. Elements such as Cu, Pb, Cr, Ni, V, Sb, and Mo were mainly associated with exhaust and non-exhaust traffic emissions.

Atmospheric Metal Biomonitoring Along a Highway Near Atlantic Rainforest Environmental Protection Areas in Southeastern Brazil.

Vehicles are quite possibly the main sources of particulate matter, and their emissions can cause damage to surrounding ecosystems. Traditional atmospheric monitoring, however, is expensive. Therefore, airborne biomonitoring is an alternative method that allows for air quality assessment. In this study, we evaluated air quality at a federal highway (BR-040) close to Atlantic Rainforest remnants by quantifying metals in biomonitor tissues by ICP-MS. Tillandsia usneoides and Tillandsia stricta plants were relocated to the investigation zone and collected after five months of exposure. Metal concentration profiles were evaluated using statistical analyses, namely exposure-to-reference (ER) ratios and enrichment factors (EF). Results indicate that V, Cr, Fe, Cu, Zn and Sn enrichment were observed in all study sites. The EF for Cr, Mn, Pb, Ni, Co, Cu, Zn, Cd, and Sn ranged from high to very high, indicating anthropogenic sources. Both species were effective atmospheric biomonitors, proving to be an important tool, mainly in areas where conventional monitoring is not possible.

Where trees cannot grow – Particulate matter accumulation by urban meadows

It has already been proven that trees and shrubs, can efficiently remove particulate matter (PM) from air. However, almost nothing is known about PM accumulation by herbaceous plants (grasses and forbs) found in urban meadows. Meadows, unlike trees and shrubs, can be located close to roads, one of the main sources of PM in cites. The aim of this study was to investigate the tolerance to urban condition and PM accumulation in the immediate roads vicinity of selected plants species in urban meadows. PM accumulation of annual and perennial meadows was compared with that of lawns. Results were interpreted in the context of species composition, biomass production, soil conditions and ambient PM concentrations. Of the species grown in annual meadows, the highest PM accumulation was found in Achillea millefolium L., Chenopodium album L. and Echium vulgare L., while Centaurea scabiosa L., Echium vulgare L. and Convolvulus arvensis L. accumulated the largest amounts of PM in perennial meadows. PM deposition on plants was positively correlated with a feathery leaf shape. For species in the annual meadows, a positive correlation was also found between PM accumulation and the wax content on plants. The presence of hairs on leaves, leaf size and plant growth pattern had no effect on PM deposition on plants. PM accumulation in one square metre of urban meadow was on average greater than that of lawn, regardless of meadow species' composition, age and location. The greatest accumulation of PM was found in a perennial meadow with low biodiversity but the greatest biomass. It would appear that the biomass produced by meadows and canopy structure has a crucial impact on the amount of PM accumulated by meadow plants. The results obtained indicate that meadows could be an important element of nature-based solutions for mitigating air pollution in urbanised areas.

Seasonal Variations in the Chemical Composition of Indoor and Outdoor PM10 in University Classrooms

In the VIEPI project (Integrated evaluation of the exposure to indoor particulate matter) framework, we carried out a 1-year study of the concentration and chemical composition of particulate matter (PM) in a 5 story building in the Sapienza University of Rome (Italy). Each sampling had a duration of 1 month and was carried out indoors and outdoors in six classrooms. The chemical analyses were grouped to obtain information about the main PM sources. Micro-elements in their soluble and insoluble fractions were used to trace additional sources. Indoor PM composition was dominated by soil components and, to a lesser extent, by the organics, which substantially increased when people crowded the sites. The penetration of PM components was regulated by their chemical nature and by the dimensions of the particles in which they were contained. For the first time in crowded indoor environments, three different chemical assays aimed to determine PM redox properties complemented chemical composition measurements. These preliminary tests showed that substantially different redox properties characterised atmospheric particles in indoor and outdoor sites. The innovative characteristics of this study (time duration, number of considered environments) were essential to obtain relevant information about PM composition and sources in indoor academic environments and the occupants’ role.

Temperature Effect on Particulate Matter Concentrations PM 10 during the heating season in Burgas

In the present paper, the dynamics of particulate matter (PM) concentration during the heating season was studied with respect to the seasonal dynamics of the temperature recorded at two measuring sites from the National system for monitoring of air quality in Burgas. The automated measuring stations (AMS) selected for the present study are located in Dolno Ezerovo (DE) and Meden Rudnik (MR) in the municipality of Burgas. This study looks at the impacts of Temperature on localised PM10 concentrations in an urban area of Burgas over the winter period. The levels of PM 10 pollution is an important characteristic for the quality of life in urban environment. The main source of PM 10 emissions is considered to be the domestic heating with wood which varies with the values of the temperature during the heating season.

NOx-Reduction Performance Test for TiO2 Paint.

In South Korea, the gradual increase in particulate matter generation has received significant attention from central and local governments. Exhaust gas, which contains nitrogen oxides (NOx), is one of the main sources of particulate matter. In this study, the reduction of NOx using a coating material mixed with a titanium dioxide (TiO2) photocatalyst was demonstrated. The NOx reduction performance of the TiO2 photocatalyst-infused coating was evaluated by applying the ISO 22197-1: 2007 standard. Subsequently, the performance was evaluated by changing the NO gas concentration and ultraviolet (UV)-A irradiance under standard experimental conditions. It was determined that NOx reduction can be achieved even if the NO gas concentration and UV-A irradiance are lower than those under the standard conditions when the TiO2 photocatalyst-infused coating was used. This study revealed that NOx reduction can be realized through TiO2 photocatalyst-infused coating in winter or cloudy days with a low solar altitude. It was also confirmed that compared with the UV-A irradiance, the NO gas concentration has a greater effect on the NOx reduction performance of the TiO2 photocatalyst-infused coating. These findings can be used to evaluate a variety of construction materials with TiO2 photocatalysts in the future.

Assessment of foliar dust particle retention and toxic metal accumulation ability of fifteen roadside tree species: Relationship and mechanism

The resuspension of urban road dust particles with high concentration of toxic metals becomes one of the main sources of particulate matter that affects air quality and the health of human beings. To address this problem, foliar dust capture ability and toxic metal accumulation capacity are evaluated through 15 tree and shrub species collected from three main roads in Nanjing. The element analysis results show that traffic, industry and the combustion of chemical fuel are important sources of road dust and its bound Cu, Zn, Cr and Pb. Among the plants, Cedrus deodara has the highest dust retention ability of 75.4 μg cm−2d−1, followed by Nerium indicum and Acer palmatum, while Platamus orientalis exhibits the lowest dust capture ability of 9.19 μg cm−2d−1, which is related to the microstructure feature of the plant leaf. Leaf particles in different size fraction differ among the species, but fine particles (PM < 2.5 μm) predominate in most cases. Nerium indicum, Cerasus yedoensis and Salix babylonica are the three species that accumulate the highest amounts of Cu, Zn, Cr and Pb. Moreover, a significant positive correlation between foliar toxic metal and dust retention amounts (especially fine particles) was found, indicating foliar uptake of toxic metals after deposition of dust particles on the leaf surface. Taken together, plant leaves can simultaneously capture road dust and its bound toxic metals. Moreover, Nerium indicum could be used as an urban landscape barrier for road dust and toxic metals.

Source Apportionment of Coarse Particulate Matter (PM10) in Yangon, Myanmar.

The Republic of the Union of Myanmar is one of many developing countries facing concerns about particulate matter (PM). Previously, a preliminary study of PM2.5 in 2018 suggested that the main source of PM in Yangon, the former capital, was vehicle emissions. However, this suggestion was not supported by any chemical composition data. In this study, to fill that gap, we quantitatively determined source contributions to coarse particulate matter (PM10) in Yangon, Myanmar. PM10 samples were collected in Yangon from May 2017 to April 2018 and chemically analyzed to determine composition. Chemical composition data for these samples were then used in the Chemical Mass Balance (CMB) model to identify the major sources of particulate matter in this area. The results indicate that PM10 composition varies seasonally according to both meteorological factors (e.g., precipitation and temperature) and human activities (e.g., firewood and yard waste burning). The major sources of PM in Yangon annually were dust, secondary inorganic aerosols (SIA), and secondary organic aerosols (SOA), while contributions from biomass burning were more important during the winter months.

Influences of exhaust load and injection timing on particle number emissions in a gasoline direct injection engine

The effects of exhaust load and injection timing on particle emission and combustion characteristics were investigated using a single-cylinder gasoline engine equipped with a direct injection system. Particulate matter emission was counted by PPS-M, and the cylinder pressure was measured to analyze the combustion phasing. An exhaust valve was installed to simulate an exhaust load caused by a gasoline particulate filter, and the exhaust load between the exhaust port and after-treatment system was varied with increasing exhaust pressure from 0.1 bar to 0.4 bar as a gauge pressure. Injection timing was swept from BTDC 330 deg to BTDC 210 deg during the intake process to enhance the homogeneity of the mixture.The main source of particulate matter at an early injection timing (i.e., BTDC 330 deg) is the fuel film on top of the piston. In addition, the homogeneity of the fuel/air mixture is the most important factor for particle number emission for the late injection case. In-cylinder temperature increased during fuel injection, and the fuel/air mixture became more homogeneous due to the increased internal EGR caused by the exhaust load. As a result, the experimental result showed that a maximum 75% reduction of particle number emission in early injection was achieved by increasing exhaust load from 0.1 bar to 0.4 bar in gauge pressure.