Fugitive Dust Research Articles

Characteristics, sources and health risk assessment of trace metals and polycyclic aromatic hydrocarbons in PM2.5 from Hefei, China.

Trace metals (TRs) and polycyclic aromatic hydrocarbons (PAHs) are major toxic components of fine particulate matter (PM2.5) and related to various health adverse outcomes. The study aims to get a better understanding of the contents, sources and risks of PM2.5-bounded TRs and PAHs in Hefei, China, during the period of 2019-2021. We collected 504 samples and measured twelve TRs and sixteen priority PAHs by inductively coupled plasma mass spectrometry and high-performance liquid chromatography. The annual mass concentrations of PM2.5 was fluctuated in the year of 2019-2021 at 50.95, 47.48 and 59.38μg/m3, with seasonal variations in rank order of winter > spring > autumn > summer. The median concentrations of PM2.5-bounded ƩTRs and ƩPAHs were also fluctuated, 132.85, 80.93 and 120.27ng/m3 for ƩTRs, 2.57, 5.85 and 2.97ng/m3 for ƩPAHs, in the year of 2019, 2020 and 2021, respectively. Seasonal variations of ƩTRs and ƩPAHs show the highest concentration in winter. Positive matrix factorization was used for identified pollution emission sources, and TRs mainly originated from coal combustion, traffic emission and fugitive dust, while PAHs stemmed from biomass, diesel, gasoline and coal combustion. Health risk assessment indicated that adults were more vulnerable than children, the carcinogenic risk assessment of As and Cr manifested a certain degree of cancer risk (1.0 × 10-6 < CR < 1.0 × 10-4) in adults group, and health risks of TRs were higher than PAHs in Hefei. These findings suggest that PM2.5-bounded TRs and PAHs should be considered when making emission control strategies for air pollution, and winter, combustion sources and adults should achieve more policy attention to decrease exposure risks in Hefei.

Spatial distribution of selenium and other potentially toxic elements surrounding mountaintop coal mines in the Elk Valley, British Columbia, Canada

Despite the extensive use of mountaintop coal mining in the Elk Valley, British Columbia, Canada's largest metallurgical coal-producing region, little is known about the transport and deposition of fugitive dust emissions within its mountain landscape. This study aimed to assess the extent and spatial distribution of selenium and other potentially toxic elements (PTEs) near the town of Sparwood originating from fugitive dust emitted from two mountaintop coal mines. To achieve these objectives concentrations of 47 elements within moss tissues of Hylocomium splendens, Pleurozium schreberi, and Ptilium crista-castrensis were analyzed from 19 locations between May 29 to June 1, 2022. Contamination factors were then calculated to identify areas of contamination, along with generalized additive models to assess the relationship between selenium and the mines. Finally, Pearson correlation coefficients were calculated between selenium and other PTEs to determine which exhibited similar behaviour. This study found that selenium concentrations are a function of proximity to mountaintop mines, and the region's topographic features and prevailing wind patterns play a role in the transport and deposition of fugitive dust. Contamination is highest immediately surrounding mines and decreases at increasing distances, with the region's steep mountain ridges shielding the deposition of some fugitive dust when acting as a geographic barrier between adjacent valleys. Furthermore, silver, germanium, nickel, uranium, vanadium, and zirconium were identified as other PTEs of concern. The implications of this study are significant as it demonstrated the extent and spatial distribution of contaminants originating from fugitive dust emissions surrounding mountaintop mines and some of the controls to its distribution in mountain regions. As Canada and other mining jurisdictions look to expand critical mineral development, it will be important for proper risk assessment and mitigation in mountain regions to limit community and environmental exposure to contaminants within fugitive dust.

Trace elements in the culturally significant plant Sarracenia purpurea in proximity to dust sources in the oil sands region of Alberta, Canada

Accessible populations of plants are critical to the meaningful exercise of Aboriginal and treaty rights in Canada. In the oil sands region of Alberta, populations of culturally significant plant species overlap with extensive oil and gas development. This has led to a host of questions and concerns related to plant health and integrity from both Indigenous communities and western scientists. Here, we assessed trace element concentrations in the northern pitcher-plant (tsala’ t'ile; Sarracenia purpurea L.) with a focus on elements associated with fugitive dust and bitumen. Plant leaves were collected using clean methods and washed prior to analyses in an ultra-clean, metal-free laboratory. Pitcher-plant was an excellent model for assessing the impacts of industrial development on a culturally important, vulnerable species. Although concentrations of trace elements in pitcher-plant were low and not indicative of a toxicological concern, we saw clear dust signatures in plant tissues related to road and surface mine proximity. Elements associated with fugitive dust and bitumen extraction declined exponentially with increasing distance from a surface mine, a well-established regional pattern. However, our analyses also captured localized spikes in trace element concentrations within 300 m of unpaved roads. These local patterns are more poorly quantified at the regional scale but are indicative of the burden to Indigenous harvesters wishing to access plant populations that are not impacted by dust. Further work to directly quantify dust loads on culturally significant plants will help to define the amount of harvesting area lost to Indigenous communities due to dust impacts.

Characterization and Health Risk of Heavy Metals in PM2.5 from Road Fugitive Dust in Five Cities of Yunnan Province

In order to study the contents, sources, and health risk of PM2.5 in road fugitive dust in Yunnan, road fugitive dust samples were collected from five typical cities including Kunming, Baoshan, Wenshan, Zhaotong, and Yuxi. Particulate matter resuspension technology was used to levitate the dust samples and collect PM2.5. Eight heavy metals including chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), selenium (As), cadmium (Cd), and lead (Pb) in PM2.5 were detected using ICP-MS. The results showed that the contents of Cr, Ni, Cu, Zn, and Pb in road fugitive dust seriously exceeded the background values of Yunnan soil. The enrichment factors showed that most of the heavy metals in PM2.5 of road fugitive dust in the five cities of Yunnan were moderately enriched and strongly enriched, which were greatly influenced by human activities. The results of correlation analysis and principal component analysis showed that the heavy metals in PM2.5 of road fugitive dust in Yunnan were all affected by soil and traffic sources. The other sources varied greatly in different cities:Kunming was affected by iron and steel melting sources, Baoshan and Yuxi were affected by non-ferrous metal smelting sources, and Zhaotong was affected by coal sources. Health risk analysis showed that Cr, Pb, and As in road fugitive dust PM2.5 had non-carcinogenic risk in children in Kunming, Yuxi, and Zhaotong, respectively, and Cr in Kunming also had a lifetime carcinogenic risk.

Experimental study on electrostatic migration of different mineral particles composing lunar dust under electron irradiation

Dust electrostatic migration is one of the primary causes of dust events on the surface of airless celestial bodies, which can result in multiple dust phenomena, including lunar horizon glow and dust pools, and also offer crucial insights into the evolution of the surface materials of airless celestial bodies. To date, the characteristics and laws of dust electrostatic migration are still not well understood. Here, we report the electrostatic migration characteristics of pyroxene, olivine, and ilmenite particles measured by the laser Doppler method and compare them with the findings of anorthite particles in previous experiments to recognize the differential migration characteristics of different mineral components in the lunar dust. The results demonstrate that the particle sizes of most moving pyroxene and olivine particles are in the range of 0–10 μm, and their vertical velocities are typically less than 2 m s−1, which are consistent with the previous studies. The cohesive force between the dust particles is probably what causes the difference in the migration rates of various insulating minerals. Note that no moving ilmenite particles were detected probably due to the material’s good conductivity. It can be speculated that the concentration of fugitive dust in the lunar mare is affected by the ilmenite content, but further research is needed to determine how low ilmenite content can cause dust migration.

A Critical Study on the Management of Innovative Fugitive Coal Dust Pollution Control Practices for a Cleaner Industrial Environment

The entire world including India is inevitably dependent on coal-based energy. Thus, the consumption of coal happens to be maximum and most frequent in comparison to other minerals. But the consumption of coal gives rise to exploitation of coal in situ and thus increases the dust create from the same. Not only the coal dust is produced at the extraction site, the sources are multiple including the transportation, dumping sites etc. The very nature of coal in terms of self-combustion and self-heating aggravates the working environment in industries giving rise to hazards and health problems. The traditional practices of suppressing and controlling fugitive dust are having their own limitations and deficiencies. Therefore, the policymakers, the concerned authorities as well as the industry personnel are constantly searching for innovative approaches which can give better dividends. In this regard, many experiments and techniques proven to be successful to a substantial extent. However, the management of these techniques has to be multi-dimensional and multifaceted. This study conducted at different coal mines in Odisha has been an attempt to understand the deficiencies in the current practices and the benefits of adopting innovations in controlling the fugitive dust polluting air and other environmental elements. This also examines the managerial implications on practicing the innovations towards making a cleaner and industrial environment.

Chemical characteristics and spatiotemporal variation of marine fine particles for clustered channels of air masses transporting toward remote background sites in East Asia

This study investigated the chemical characteristics, spatiotemporal distribution, and source apportionment of marine fine particles (PM2.5) for clustered transport channels/routes of air masses moving toward three remote sites in East Asia. Six transport routes in three channels were clustered based on backward trajectory simulation (BTS) in the order of: West Channel > East Channel > South Channel. Air masses transported toward Dongsha Island (DS) came mainly from the West Channel, while those transported toward Green Island (GR) and Kenting Peninsula (KT) came mostly from the East Channel. High PM2.5 commonly occurred from late fall to early spring during the periods of Asian Northeastern Monsoons (ANMs). Marine PM2.5 was dominated by water-soluble ions (WSIs) which were predominated by secondary inorganic aerosols (SIAs). Although the metallic content of PM2.5 was predominated by crustal elements (Ca, K, Mg, Fe, and Al), enrichment factor clearly showed that trace metals (Ti, Cr, Mn, Ni, Cu, and Zn) came mainly from anthropogenic sources. Organic carbon (OC) was superior to elemental carbon (EC), while OC/EC and SOC/OC ratios in winter and spring were higher than those in other two seasons. Similar trends were observed for levoglucosan and organic acids. The mass ratio of malonic acid and succinic acid (M/S) was commonly higher than unity, showing the influences of biomass burning (BB) and secondary organic aerosols (SOAs) on marine PM2.5. We resolved that the main sources of PM2.5 were sea salts, fugitive dust, boiler combustion, and SIAs. Boiler combustion and fishing boat emissions at the site DS had higher contribution than those at the sites GR and KT. The highest/lowest contribution ratios of cross-boundary transport (CBT) were 84.9/29.6% in winter and summer, respectively.

Adverse Effects: Thirteen Homeowners Near A Blasting Quarry Bought Out By Quarry Owner

In Ontario, a blasting quarry operation, once established, is allowed to effectively operate indefinitely, as a licence to permit aggregate extraction has no expiry date. Once established, the prospect of terminating a quarry operator’s licence is virtually non-existent, regardless of the nature or number of site plan and quarry violations or adverse impacts (e.g., flyrock, noise, toxic fumes, fugitive dust, vibrations, drain or damage domestic wells), all due to a lack of effective government oversight (e.g., government staff shortage exacerbated by allowing self-reporting of the aggregate industry). Before a blasting or non-blasting quarry operation is permitted, the owner of the quarry should be compelled to purchase potentially impacted properties, provided that in doing so the environmental impact is reduced to a “trivial” level and the surrounding community is not destabilized. Otherwise, once a quarry is operational, the only remedy available to the municipality and impacted property owners is to launch a civil action at considerable time and expense, a process that can drag on for years with no guarantee of success. Sometimes, a quarry operator will voluntarily commit to purchase adversely impacted properties, but sometimes the acquisitions are undertaken surreptitiously, and require the property owner to sign a non-disclosure agreement. This case study pertains to a number of adversely effected homeowners whose homes were bought out by the owners of the Acton Quarry in Halton Hills, Ontario. They concealed their true identity through the use of numbered companies and one with the delightful sounding name (Snowfarm Ltd.) when purchasing the houses and in the process destabilized the community.

Connecting oxidative potential with organic carbon molecule composition and source-specific apportionment in PM2.5 in Xi'an, China

Epidemiological studies have suggested that exposure to excessive amounts of particle-bound reactive oxygen species (ROS) pollution can lead to a range of health problems. To identify the chemical composition and sources of particulate matter of diameter <2.5 μm (PM2.5)-bound ROS, high-time-resolution PM2.5 samples were collected in Xi'an, China in the periods July 24 to August 5, 2017 (summer), and January 1 to 6, 2017 (winter). Dithiothreitol (DTT) assay was used to measure the oxidative potential of PM2.5-bound ROS. The associations of six types of molecular compositions with ROS were evaluated, and source-specific contributions to ROS were quantified. The results indicated greater activity and diurnal fluctuations in PM2.5-bound ROS in winter than in summer. The mass-normalised DTT consumption rate (DTTm) reached a peak at 8:00 a.m. in summer for polluted and nonpolluted days. In winter, levels of ROS were higher during the day than night, regardless of PM2.5 pollution level. In summer, CHNO and CHOS had the greatest effect on DTTm on polluted days and CHO and CHNOS had the greatest effect on DTTm on nonpolluted days. On polluted days in winter, all molecules (CHO, CHNO, CHOS, CHNOS, CHN and CHNS) investigated in this study had limited effects on DTTm. DTTm on nonpolluted days was mainly affected by CHNO and CHNS. CHNO and CHNOS molecules from secondary reactions favoured ROS production. Results from source apportionment based on positive matrix factorization showed that in summer, vehicle emission was the primary contributor to ROS generation (41.3%), followed by secondary formation (33.7%), fugitive dust (18.6%), and coal combustion (6.3%), whereas in winter, biomass burning and secondary formation were the primary contributors (>58%) to ROS. Our work helps clarify the mechanisms of ROS formation and contributes to theoretical research on PM2.5 toxicity.

Microbial‑induced carbonate precipitation (MICP) technology: a review on the fundamentals and engineering applications.

The microbial‑induced carbonate precipitation (MICP), as an emerging biomineralization technology mediated by specific bacteria, has been a popular research focus for scientists and engineers through the previous two decades as an interdisciplinary approach. It provides cutting-edge solutions for various engineering problems emerging in the context of frequent and intense human activities. This paper is aimed at reviewing the fundaments and engineering applications of the MICP technology through existing studies, covering realistic need in geotechnical engineering, construction materials, hydraulic engineering, geological engineering, and environmental engineering. It adds a new perspective on the feasibility and difficulty for field practice. Analysis and discussion within different parts are generally carried out based on specific considerations in each field. MICP may bring comprehensive improvement of static and dynamic characteristics of geomaterials, thus enhancing their bearing capacity and resisting liquefication. It helps produce eco-friendly and durable building materials. MICP is a promising and cost-efficient technology in preserving water resources and subsurface fluid leakage. Piping, internal erosion and surface erosion could also be addressed by this technology. MICP has been proved suitable for stabilizing soils and shows promise in dealing with problematic soils like bentonite and expansive soils. It is also envisaged that this technology may be used to mitigate against impacts of geological hazards such as liquefaction associated with earthquakes. Moreover, global environment issues including fugitive dust, contaminated soil and climate change problems are assumed to be palliated or even removed via the positive effects of this technology. Bioaugmentation, biostimulation, and enzymatic approach are three feasible paths for MICP. Decision makers should choose a compatible, efficient and economical way among them and develop an on-site solution based on engineering conditions. To further decrease the cost and energy consumption of the MICP technology, it is reasonable to make full use of industrial by-products or wastes and non-sterilized media. The prospective direction of this technology is to make construction more intelligent without human intervention, such as autogenous healing. To reach this destination, MICP could be coupled with other techniques like encapsulation and ductile fibers. MICP is undoubtfully a mainstream engineering technology for the future, while ecological balance, environmental impact and industrial applicability should still be cautiously treated in its real practice.

Route-based chemical significance and source origin of marine PM2.5 at three remote islands in East Asia: Spatiotemporal variation and long-range transport

We explored the route-based chemical significance, spatial distribution, temporal variation, and source origin of fine particles (PM2.5) in East Asia. Marine PM2.5 was sampled at three remote islands in the Taiwan Strait (TS) and the South China Sea (SCS) to identify their chemical significance. High PM2.5 concentrations concurred with LRT of northerly polluted air. Moreover, daytime PM2.5 levels were mostly greater than nighttime. Secondary inorganic aerosols (SIAs) accounted for 42.4–79.9% of water-soluble ions (WSIs) in PM2.5, which were commonly higher in spring and winter. Although crustal elements suppressed the metallic contents of PM2.5, trace elements (V, Cr, Mn, Ni, Zn, and Cd) came dominantly from anthropogenic origins. Additionally, OC/EC ratios >2.0 were observed due to higher organic carbon (OC) than elemental carbon (EC) during the Asian Northeastern Monsoons (ANMs) commonly in spring and winter. Levoglucosan and oxalic acid were, respectively, the most abundant anhydrosugars (ASs) and organic acids (OAs) in PM2.5, and both descended from the north to the south. The mass ratios of malonic and succinic acids (M/S) were in the range of 0.95–1.41, suggesting a high correlation of marine PM2.5 with secondary organic aerosols (SOAs). Source resolution of PM2.5 showed that sea salts, fugitive dust, mobile sources, secondary sulfate and nitrate were the major sources of PM2.5. In particular, anthropogenic origins and biomass burning (BB) contributed notably to PM2.5 during the ANMs. Overall, compared to natural sources (21–48%), anthropogenic sources (25–57%) contributed more to marine PM2.5 in East Asia.

Indoor/outdoor relationships of PM2.5-associated toxic metals/metalloids at a rural residence in North China: Sources and probabilistic health risks

Levels of toxic metals/metalloids (TMs) in indoor air are of vital importance to the health of residents due to the high toxicity of TMs and the fact that the majority of the time is spent indoors. Currently, the relationship between indoor and outdoor TMs at rural residences remains unclear. In this study, 24-h samples of indoor and outdoor fine particulate matter (PM2.5) were simultaneously collected at a rural residence during the heating season in North China. The results revealed that the concentrations of PM2.5 and certain TMs indoors were higher than those outdoors (p < 0.05), and the low correlation between the indoor and outdoor concentrations indicates the slight influences of indoor and outdoor TMs. Among the TMs, the As concentration exceeded its environmental threshold (6 ng/m3) both indoors and outdoors. An integrated approach comprising positive matrix factorization (PMF), infiltration factor analysis, correlation analysis, and polar plot analysis was used to identify the sources of TMs. Regarding indoor emissions, indoor coal combustion, indoor cooking sources and fugitive dust were identified, while in regard to outdoor emissions, the sources included traffic emissions, coal combustion, fugitive dust, and industrial emissions. The probabilistic risk estimated via Monte Carlo simulations indicated that both the noncancer health risk (HI) and cancer risk (TCR) were unacceptable as the corresponding safety thresholds were exceeded (HI > 1 and TCR>10−4). In particular, As dominated both the noncancer and cancer risks (nearly 40%). Therefore, more efforts are needed to reduce the As concentration and coal combustion source in rural areas.

Coarse particulate matter air quality in East Asia: implications for fine particulate nitrate

Abstract. Air quality network data in China and South Korea show very high year-round mass concentrations of coarse particulate matter (PM), as inferred by the difference between PM10 and PM2.5. Coarse PM concentrations in 2015 averaged 52 µg m−3 in the North China Plain (NCP) and 23 µg m−3 in the Seoul Metropolitan Area (SMA), contributing nearly half of PM10. Strong daily correlations between coarse PM and carbon monoxide imply a dominant source from anthropogenic fugitive dust. Coarse PM concentrations in the NCP and the SMA decreased by 21 % from 2015 to 2019 and further dropped abruptly in 2020 due to COVID-19 reductions in construction and vehicle traffic. Anthropogenic coarse PM is generally not included in air quality models but scavenges nitric acid to suppress the formation of fine particulate nitrate, a major contributor to PM2.5 pollution. GEOS-Chem model simulation of surface and aircraft observations from the Korea–United States Air Quality (KORUS-AQ) campaign over the SMA in May–June 2016 shows that consideration of anthropogenic coarse PM largely resolves the previous model overestimate of fine particulate nitrate. The effect is smaller in the NCP which has a larger excess of ammonia. Model sensitivity simulations for 2015–2019 show that decreasing anthropogenic coarse PM directly increases PM2.5 nitrate in summer, offsetting 80 % the effect of nitrogen oxide and ammonia emission controls, while in winter the presence of coarse PM increases the sensitivity of PM2.5 nitrate to ammonia and sulfur dioxide emissions. Decreasing coarse PM helps to explain the lack of decrease in wintertime PM2.5 nitrate observed in the NCP and the SMA over the 2015–2021 period despite decreases in nitrogen oxide and ammonia emissions. Continuing decrease of fugitive dust pollution means that more stringent nitrogen oxide and ammonia emission controls will be required to successfully decrease PM2.5 nitrate.

Characteristics and Source Apportionment of Atmospheric Ion Deposition During Winter and Spring in the Core Area of Beijing

In recent years, the Ministry of Ecology and Environment and the Beijing Municipal Government have continuously strengthened the control indicators of dustfall. In order to grasp the characteristics and sources of ion deposition in dustfall, the filtration method and ion chromatography were used to determine the dustfall and ion deposition during winter and spring in the core area of Beijing, and the PMF model was carried out to analyze the sources of ion deposition. The results indicated:① the average values of ion deposition and its proportion in dustfall were 0.87 t·(km2·30 d)-1 and 14.2%, respectively. The dustfall and ion deposition on working days were 1.3 times and 0.7 times that on rest days, respectively. ② The coefficient of determination in the linear equations between ion deposition and precipitation, relative humidity, temperature, and average wind speed were 0.54, 0.16, 0.15, and 0.02, respectively. In addition, the coefficient of determination in the linear equations between ion deposition and PM2.5 concentration and dustfall were 0.26 and 0.17, respectively. Therefore, controlling the concentration of PM2.5 was crucial to treating ion deposition. ③ Anions and cations accounted for 61.6% and 38.4%, respectively, in the ion deposition, and SO42-, NO3-, and NH4+ accounted for 60.6% in total. The ratio of anion and cation charge deposition was 0.70, and the dustfall was alkaline. The ρ(NO3-)/ρ(SO42-) in the ion deposition was 0.66, which was higher than that of 15 years ago. ④ The contribution rates of secondary sources, fugitive dust sources, combustion sources, snow-melting agent sources, and other sources were 51.7%, 17.7%, 13.5%, 13.5%, and 3.6%, respectively.

Heterogeneous characteristics and absorption enhancement of refractory black carbon in an urban city of China

In this study, field measurement was conducted using an integrated online monitoring system to characterize heterogeneous properties and light absorption of refractory black carbon (rBC). rBC particles are mainly from the incomplete combustion of carbonaceous fuels. With the data collected from a single particle soot photometer, thickly coated (BCkc) and thinly coated (BCnc) particles are characterized with their lag times. With different responses to the precipitation, a dramatical decline of 83 % in the number concentration of BCkc is shown after rainfall, while that of BCnc decreases by 39 %. There is a contrast in core size distribution that BCkc is always with larger particle sizes but has smaller core mass median diameters (MMD) than BCnc. The mean rBC-containing particle mass absorption cross-section (MAC) is 6.70 ± 1.52 m2 g−1, while the corresponding rBC core is 4.90 ± 1.02 m2 g−1. Interestingly, there are wide variations in the core MAC values which range by 57 % from 3.79 to 5.95 m2 g−1, which are also closely related to those of the whole rBC-containing particles with a Pearson correlation of 0.58 (p < 0.01). Errors would be made if we eliminate the discrepancies and set the core MAC as a constant when calculating absorption enhancement (Eabs). In this study, the mean Eabs is 1.37 ± 0.11 while the source apportionment shows that there are five contributors of Eabs including secondary aging (37 %), coal combustion (26 %), fugitive dust (15 %), biomass burning (13 %) and traffic-related emissions (9 %). Secondary aging is found to be the highest contributor due to the liquid phase reactions in formations of secondary inorganic aerosol. Our study characterizes property diversities and provides insights into the sources impacting the light absorption of rBC and will be helpful for controlling it in the future.

Seasonal Variations, Size Distributions, and Sources of Chemical Components of Submicron Particulate Matter in Nanjing

Size-segregated particulate matter (PM) samples were collected in different seasons from 2016 to 2017 at the Xianlin Campus of Nanjing University. Mass concentrations of water-soluble inorganic ions, carbonaceous components, and elements were analyzed for PM with an aerodynamic diameter ≤ 1.1 μm (PM1.1; <0.4 μm, 0.4-0.7 μm, and 0.7-1.1 μm). The results showed that PM1.1, OC, NO3-, SO42-, and NH4+ exhibited higher ambient levels in fall-winter than those in spring-summer, which was attributed to the changes in local diffusion conditions, evaporation, and decomposition of non-refractory components. Elemental carbon (EC) reached its maximum concentration[(1.87±0.98) μg·m-3]in spring due to the increase in industrial and road dust resuspension. According to the characteristic ratio between bulk components, the anions in PM1.1 were dominated by NO3-, SO42-, and Cl- in Nanjing, and the carbonaceous components were mainly from fossil fuel combustions and associated aging processes. As the ambient temperature increased, the size distributions of thermo-unstable components including NH4+, NO3-, and OC shifted towards finer particles, whereas EC became more enriched in coarse particles, possibly due to the increase in emission intensity of motor vehicles and fugitive dust contributions. Since high relative humidity (>70%) is often accompanied by high temperature (>20℃) and improved diffusion conditions, a relative humidity of 60%-70% was more conducive to the formation of secondary inorganic ions in PM1.1. Source apportionment results based on the speciation data of PM1.1 showed that secondary formation processes[(66.6±18.3)%]and dust resuspension[(16.8±14.8)%]were the main contributors to PM1.1 in Nanjing, and further control of the emissions of gaseous precursors and dust is necessary.

Numerical Simulation Study on Spatial Diffusion Behavior of Non-Point Source Fugitive Dust under Different Enclosure Heights

Non-point source fugitive dust produced during municipal road construction is one of the main ambient air pollutants gravely threatening the life and health of construction workers and residents around construction areas. In this study, a gas-solid two-phase flow model is used to simulate the diffusion behavior of non-point source dust with different enclosure heights under wind loads. Moreover, the inhibitory effect of the enclosure on the diffusion of non-point source dust from construction to residential areas is analyzed. The results show that the physical blocking and reflux effects of the enclosure can effectively restrain dust diffusion. When the enclosure height is 3-3.5 m, the concentration of particulate matter in most sections of residential areas can be reduced to less than 40 μg/m3. Moreover, when the wind speed is 1-5 m/s and the enclosure height is 2-3.5 m, the diffusion height of non-point source dust particles above the enclosure is concentrated in the range 1.5-2 m. This study provides a scientific basis for setting the heights of enclosures and atomization sprinklers at construction sites. Further, effective measures are proposed to reduce the impact of non-point source dust on the air environment of residential areas and health of residents.

Performance of Repair Mortars Containing Natural Cellulose Fiber for Fugitive Dust Reduction

Performance of Repair Mortars Containing Natural Cellulose Fiber for Fugitive Dust Reduction

Evaluation of wetting measures and capture efficiencies of fugitive dust emitted from a limestone pile: Experiments and artificial neural network

In windy conditions, dry bulk material storage sites for limestone fugitively emit dust, causing occupational hazards and posing harmful health effects to nearby residents. According to this investigation, the threshold friction velocity for the limestone was 7 m s−1. As wind speed increases from 7 to 10 m s−1, the concentrations of TSP, PM10, and PM2.5 rose by 148%, 121%, and 76%, respectively. Separate tests were conducted to evaluate fog cannons' and heavy-duty sprinklers' ability to capture TSP, PM10, and PM2.5 and prevent re-suspension from the pile's surface. Eight cases of parameter combinations were investigated, where PM2.5 had the lowest dust capture efficiencies in six instances, while TSP had the highest dust capture in all eight cases. Low spray angles and intermittent water flow regimes showed the best dust collection efficiency. For the fog cannon it was 85.3% and for the heavy-duty sprinkler, it was 79.5%, and they occurred at low and high wind velocities, respectively. The wettability of dust particles smaller than 4 µm in diameter was more difficult than that of larger particles, because the size differences between dust particles and wetting agent's droplets reduces the probability of collision. An artificial neural network was applied to predict dust capture efficiencies from model parameters such as wind speed, spray angle, and water supply regimes. The relative errors in the predicted capture efficiencies for TSP, PM10, and PM2.5 capture were 1.86–4.73%, 2.15–4.57%, and 1.99–6.53%, respectively, implying a good learning ability of the neural network. The results of different wind speed predictions were verified by the F test, where the P values for TSP, PM10, and PM2.5 ranged between 0.17–0.44, 0.18–0.45, and 0.16–0.48, respectively. Overall, intermittent waterflows and low wind speeds optimized the spread of the mist released from the fog cannon, while intermittent waterflows and higher wind speeds were necessary for the optimal performance of the heavy-duty sprinkler.

High time-resolution source apportionment and health risk assessment for PM2.5-bound elements at an industrial city in northwest China

To better respond to heavy air pollution, the local government of Baoji City, a traditionally industry dominated city in northwest China, released several warning levels between December 2019 and January 2020. The system aims to provide a more efficient control of pollution sources. In this study, a high-time resolution measurement of PM2.5-bound elements was applied to capture the diurnal-scale dynamic processes associated with major pollution activities in northwest China. A series of elements were quantified and used for source apportionment using the positive matrix factorization (PMF) model. Combined with the local characteristics, nine sources were resolved with contributions in descending order: fugitive dust (36.6 %), biomass burning (20.1 %), traffic-related (10.4 %), coal combustion (10.0 %), titanium alloy smelting (7.2 %), As-related industry (6.9 %), Zn-related industry (5.6 %), molybdenum alloy smelting (2.5 %), and Cr-related industry (0.7 %). The health risk assessment indicated non-carcinogenic risks for Mn and carcinogenic risks for As and Cr in both adults and children. The cumulative non-carcinogenic risk for the elements was 3.2 times the safety threshold, while the carcinogenic risk (CR) was 6.8 and 27 times the acceptable levels for children and adults, respectively. For source-resolved risks, As- and Cr-related industry emissions showed the highest carcinogenic risk. Five of the nine resolved sources for adults have CR values 1.4 and 9.7 times the acceptable level. This study provides valuable information for developing targeted strategies to control air pollutants and protect public health.