Search

Studies revealed airports as a prominent source of ultrafine particles (UFP), which can disperse downwind to residential areas, raising health concerns. To expand our understanding of how air traffic-related emissions influence total particle number concentration (PNC) in the airport’s surrounding areas, we conduct long-term assessment of airborne particulate exposure before and after relocation of air traffic from “Otto Lilienthal” Airport (TXL) to Berlin Brandenburg Airport “Willy Brandt” (BER) in Berlin, Germany. Here, we provide insights into the spatial–temporal variability of PNC measured in 16 schools recruited for Berlin-Brandenburg Air Study (BEAR).The results show that the average PNC in Berlin was 7900 ± 7000 cm−3, consistent with other European cities. The highest median PNC was recorded in spring (6700 cm−3) and the lowest in winter (5100 cm−3). PNC showed a bi-modal increase during morning and evening hours at most measurement sites due to road-traffic emissions. A comparison between measurements at the schools and fixed monitoring sites revealed good agreement at distances up to 5 km. A noticeable decline in this agreement occurred as the distance between measurement sites increased. After TXL was closed, PNC in surrounding areas decreased by 30 %. The opposite trend was not seen after BER was re-opened after the COVID-lock-down, as the air traffic has not reached the full capacity yet. The analysis of particle number size distribution data showed that UFP number fraction exhibit seasonal variations, with higher values in spring and autumn. This can be explained by nucleation events, which notably affected PNC.The presented findings will play a pivotal role in forthcoming source attribution and epidemiological investigations, offering a holistic understanding of airports’ impact on airborne pollutant levels and their health implications. The study calls for further investigations of air-traffic-related physical–chemical pollutant properties in areas found further away (> 10 km) from airports.

Increasing demand for size-resolved identification and quantification of microplastic particles in drinking water and environmental samples requires the adequate validation of methods and techniques that can be used for this purpose. In turn, the feasibility of such validation depends on the existence of suitable certified reference materials (CRM). A new candidate reference material (RM), consisting of polyethylene terephthalate (PET) particles and a water matrix, has been developed. Here, we examine its suitability with respect to a homogeneous and stable microplastic particle number concentration across its individual units. A measurement series employing tailor-made software for automated counting and analysis of particles (TUM-ParticleTyper 2) coupled with Raman microspectroscopy showed evidence of the candidate RM homogeneity with a relative standard deviation of 12% of PET particle counts involving particle sizes >30 µm. Both the total particle count and the respective sums within distinct size classes were comparable in all selected candidate RM units. We demonstrate the feasibility of production of a reference material that is sufficiently homogeneous and stable with respect to the particle number concentration. [ABSTRACT FROM AUTHOR]

Indoor air pollution is a critical health issue. We studied particle emissions, concentration changes and size distribution mechanisms using an indoor space with air quality monitors, incense stick burning, and ventilation. Temporal changes in the concentrations of particles with sizes of 10 nm to 10 µm were monitored. Our findings show that particles affecting particle number concentration (PNC) were mainly in the Aitken mode (50–100 nm) and accumulation mode I (100–200 nm). Particle surface area concentration (PAC) was primarily in the 100–300 nm range, while particle volume concentration (PVC) was in the 100–200 nm and 300–1000 nm ranges. After extinguishing the incense sticks, ventilation was initiated. The ventilation period was split into FAO1–3 (i.e., the first 3 min, 1–3 min of ventilation system operation) and FAO4–15 (i.e., the last 12 min, 4–15 min of ventilation system operation). During FAO1–3, particle concentrations increased by 18.3 to 21.5%. This rise was due to the initial activation of the ventilation system, dispersing settled particles (mostly ≥ 41.2 nm) into the air. The FAO4–15/FAO1–3 ratio for 12.3−2489.3 nm particles was always < 1, indicating that as the ventilation continued, it effectively removed particles of < 2.5 μm. After subsequent ventilation of 15-min operation, total PNC, PAC, and PVC were 70.3%, 70.0%, and 67.8% lower than during FAO1–3 and the particle number mode diameter was 106.0 nm, with geometric standard deviations of 1.50 and 1.51 (left and right), indicating that the ventilation system was successful in removing smoke particles of all sizes simultaneously and evenly and achieved an approximate total removal efficiency of 70%, effectively filtering particles and reducing indoor air pollution. [ABSTRACT FROM AUTHOR]

Brake wear particles are generated through frictional contact between the brake disc or brake drum and the brake pads. Some of these particles may be released into the atmosphere, contributing to airborne fine particulate matter (PM2.5). In this study, an onboard system was developed and tested to measure brake wear particles emitted under real-world driving conditions. Brake wear particles were extracted from a fixed volume enclosure surrounding the pad and disc installed on the front wheel of a light-duty vehicle. Real-time data on size distribution, number concentration, PM2.5 mass, and the contribution of semi-volatiles were obtained via a suite of instruments sub-sampling from the constant volume sampler (CVS) dilution tunnel. Repeat measurements of brake particles were obtained from a 42 min bespoke drive cycle on a chassis dynamometer, from on-road tests in an urban area, and from braking events on a test track. The results showed that particle emissions coincided with braking events, with mass emissions around 1 mg/km/brake during on-road driving. Particle number emissions of low volatility particles were between 2 and 5 × 109 particles/km/brake. The highest emissions were observed under more aggressive braking. The project successfully developed a proof-of-principle measurement system for brake wear emissions from transient vehicle operation. The system shows good repeatability for stable particle metrics, such as non-volatile particle number (PN) from the solid particle counting system (SPCS), and allows for progression to a second phase of work where emissions differences between commercially available brake system components will be assessed. [ABSTRACT FROM AUTHOR]

Pollution from road vehicles enters the air environment from many sources. One such source could be if the vehicle is equipped with an auxiliary heater. They can be classified according to whether they work with diesel or gasoline and whether they heat water or air. The subject of our research series is an additional heating system that heats the air, the original fuel is gasoline. This device has been built up in a modern engine test bench, where the environmental parameters can be controlled. The length of the test cycle was chosen to be 30 min. The tested fuels were E10, E30, E100 and B7. A 30-min operating period has been chosen in the NORMAL operating mode of the device as a test cycle. The focus of the tests was particle number concentration and soot composition. The results of the particle number concentration showed that renewable fuel content significantly reduces the number concentration of the emitted particles (9.56 × 108 #/cycle for E10 vs. 1.65 × 108 #/cycle for E100), while B7 causes a significantly higher number of emissions than E10 (3.92 × 1010 #/cycle for B7). Based on the elemental analysis, most deposits are elemental carbon, but non-organic compounds are also present. Carbon (92.18 m/m% for E10), oxygen (6.34 m/m% for E10), fluorine (0.64 m/m% for E10), and zinc (0.56 m/m% for E10) have been found in the largest quantity of deposits taken form the combustion chamber. [ABSTRACT FROM AUTHOR]

Aviation has been shown to cause high particle number concentrations (PNC) in areas surrounding major airports. Particle size distribution and composition differ from motorized traffic. The objective was to study short-term effects of aviation-related UFP on respiratory health in children.In 2017–2018 a study was conducted in a school panel of 7–11 year old children (n = 161) living North and South of Schiphol Airport. Weekly supervised spirometry and exhaled nitric oxide (eNO) measurements were executed. The school panel, and an additional group of asthmatic children (n = 19), performed daily spirometry tests at home and recorded respiratory symptoms. Hourly concentrations of various size fractions of PNC and black carbon (BC) were measured at three school yards. Concentrations of aviation-related particles were estimated at the residential addresses using a dispersion model. Linear and logistic mixed models were used to investigate associations between daily air pollutant concentrations and respiratory health.PNC20, a proxy for aviation-related UFP, was virtually uncorrelated with BC and PNC50-100 (reflecting primarily motorized traffic), supporting the feasibility of separating PNC from aviation and other combustion sources. No consistent associations were found between various pollutants and supervised spirometry and eNO. Major air pollutants were significantly associated with an increase in various respiratory symptoms. Odds Ratios for previous day PNC20 per 3,598pt/cm3 were 1.13 (95%CI 1.02; 1.24) for bronchodilator use and 1.14 (95%CI 1.03; 1.26) for wheeze. Modelled aviation-related UFP at the residential addresses was also positively associated with these symptoms, corroborating the PNC20 findings. PNC20 was not associated with daily lung function, but PNC50-100 and BC were negatively associated with FEV1.PNC of different sizes indicative of aviation and other combustion sources were independently associated with an increase of respiratory symptoms and bronchodilator use in children living near a major airport. No consistent associations between aviation-related UFP with lung function was observed.

IntroductionExercising on regular basis provides countless health benefits. To ensure the health, well-being and performance of athletes, optimal indoor air quality, regular maintenance and ventilation in sport facilities are essential.MethodsThis study assessed the levels of particulate, down to the ultrafine range (PM10, PM2.5, and particle number concentration in size range of 20–1,000 nm, i.e., – PNC20-1000 nm), gaseous pollutants (total volatile organic compounds – TVOCs, CO2, and O3) and comfort parameters (temperature – T, relative humidity – RH) in different functional spaces of health clubs (n = 8), under specific occupancy and ventilation restrictions.Results and DiscussionIn all HCs human occupancy resulted in elevated particles (up to 2–3 times than those previously reported), considering mass concentrations (PM10: 1.9–988.5 μg/m3 PM2.5: 1.6–479.3 μg/m3) and number (PNC 1.23 × 103 – 9.14 × 104 #/cm3). Coarse and fine PM indicated a common origin (rs = 0.888–0.909), while PNC showed low–moderate associations with particle mass (rs = 0.264–0.629). In addition, up to twice-higher PM and PNC were detected in cardiofitness & bodybuilding (C&B) areas as these spaces were the most frequented, reinforcing the impacts of occupational activities. In all HCs, TVOCs (0.01–39.67 mg/m3) highly exceeded the existent protection thresholds (1.6–8.9 times) due to the frequent use of cleaning products and disinfectants (2–28 times higher than in previous works). On contrary to PM and PNC, TVOCs were higher (1.1–4.2 times) in studios than in C&B areas, due to the limited ventilations combined with the smaller room areas/volumes. The occupancy restrictions also led to reduced CO2 (122–6,914 mg/m3) than previously observed, with the lowest values in HCs with natural airing. Finally, the specific recommendations for RH and T in sport facilities were largely unmet thus emphasizing the need of proper ventilation procedures in these spaces.

Low-cost Particulate Matter (PM) sensors offer an excellent opportunity to improve our knowledge about this type of pollution. Their size and cost, which support multi-node network deployment, along with their temporal resolution, enable them to report fine spatio-temporal resolution for a given area. These sensors have known issues across performance metrics. Generally, the literature focuses on the PM mass concentration reported by these sensors, but some models of sensors also report Particle Number Concentrations (PNCs) segregated into different PM size ranges. In this study, eight units each of Alphasense OPC-R1, Plantower PMS5003 and Sensirion SPS30 have been exposed, under controlled conditions, to short-lived peaks of PM generated using two different combustion sources of PM, exposing the sensors' to different particle size distributions to quantify and better understand the low-cost sensors performance across a range of relevant environmental ranges. The PNCs reported by the sensors were analysed to characterise sensor-reported particle size distribution, to determine whether sensor-reported PNCs can follow the transient variations of PM observed by the reference instruments and to determine the relative impact of different variables on the performances of the sensors. This study shows that the Alphasense OPC-R1 reported at least five size ranges independently from each other, that the Sensirion SPS30 reported two size ranges independently from each other and that all the size ranges reported by the Plantower PMS5003 were not independent of each other. It demonstrates that all sensors tested here could track the fine temporal variation of PNCs, that the Alphasense OPC-R1 could closely follow the variations of size distribution between the two sources of PM, and it shows that particle size distribution and composition are more impactful on sensor measurements than relative humidity. [ABSTRACT FROM AUTHOR]

It is necessary to predict the spatial variation in particle number concentration (PNC) and black carbon (BC) because they are considered air pollutants associated with traffic and many diseases. In this study, land use regression (LUR) models for PNC and BC were developed based on a mobile monitoring campaign in January 2020 in Lanzhou, and the performance of models was evaluated with hold-out validation (HV) and leave-one-out cross-validation (LOOCV). The results show that the adjusted R2 of the LUR models for PNC and BC are 0.51 and 0.53, respectively. The R2 of HV and LOOCV are 0.43 and 0.44, respectively, for the PNC model and 0.42 and 0.50, respectively, for the BC model. The performances of the LUR models are of a moderate level. The spatial distribution of the predicted PNC is related to the distance from water bodies. The high PNC is related to industrial pollution. The BC concentration decreases from south to north. High BC concentrations are associated with freight distribution centres and coal-fired power plants. The range of PNC particle sizes in this study is larger than in most studies. As one of few studies in Lanzhou to develop LUR models of air pollutants, it is important to accurately estimate pollutant concentrations to improve air quality and provide health benefits for residents. [ABSTRACT FROM AUTHOR]

Based on laser-diffraction technique, the maximum entropy technique is applied to measure particle number concentration and size distribution in pneumatic transport. The information of particle number concentration and size distribution can be obtained simultaneously without distort the fluid and the particle trajectories. Detailed information about the distribution of the particle size and concentration in gas-solid two-phase flows near sand-bed surface are obtained in a large-scale wind tunnel test system. The experimental result shows that particle number concentration increases linearly with the increase of the wind speed. The mean particle size decreases exponentially with height (H > 3 cm), but almost unchanged for H

The present work aimed to assess the ambient levels of air pollution with particulate matter for both mass concentrations and number of particles for various fractions in Ploiesti city during the lockdown period determined by the COVID-19 pandemic (March–June 2020). The PM10 continuously monitored data was retrieved from four air quality automatic stations that are connected to the Romanian National Network for Monitoring Air Quality and located in the city. Because no other information was available for other more dangerous fractions, we used monitoring campaigns employing the Lighthouse 3016 IAQ particle counter near the locations of monitoring stations assessing size-segregated mass fraction concentrations (PM0.5, PM1, PM2.5, PM5, PM10, and TPM) and particle number concentration (differential Δ) range between 0.3 and 10 microns during the specified timeline between 8.00 and 11.00 a.m., which were considered the morning rush hours interval. Interpolation maps estimating the spatial distribution of the mass concentrations of various PM fractions and particle number concentration were drawn using the IDW algorithm in ArcGIS 10.8.2. Regarding the particle count of 0.5 microns during the lockdown, the smallest number was recorded when the restriction of citizens' movement was declared (24 March 2020), which was 5.8-times lower (17,301.3 particles/cm3) compared to a common day outside the lockdown period (100,047.3 particles/cm3). Similar results were observed for other particle sizes. Regarding the spatial distribution of the mass concentrations, the smaller fractions were higher in the middle of the city and west (PM0.5, PM1, and PM2.5) while the PM10 was more concentrated in the west. These are strongly related to traffic patterns. The analysis is useful to establish the impact of PM and the assessment of urban exposure and better air quality planning. Long-term exposure to PM in conjunction with other dangerous air pollutants in urban aerosols of Ploiesti can lead to potential adverse effects on the population, especially for residents located in the most impacted areas. [ABSTRACT FROM AUTHOR]

Brake wear particles are generated through frictional contact between the brake disc or brake drum and the brake pads. Some of these particles may be released into the atmosphere, contributing to airborne fine particulate matter (PM2.5). In this study, an onboard system was developed and tested to measure brake wear particles emitted under real-world driving conditions. Brake wear particles were extracted from a fixed volume enclosure surrounding the pad and disc installed on the front wheel of a light-duty vehicle. Real-time data on size distribution, number concentration, PM2.5 mass, and the contribution of semi-volatiles were obtained via a suite of instruments sub-sampling from the constant volume sampler (CVS) dilution tunnel. Repeat measurements of brake particles were obtained from a 42 min bespoke drive cycle on a chassis dynamometer, from on-road tests in an urban area, and from braking events on a test track. The results showed that particle emissions coincided with braking events, with mass emissions around 1 mg/km/brake during on-road driving. Particle number emissions of low volatility particles were between 2 and 5 × 109 particles/km/brake. The highest emissions were observed under more aggressive braking. The project successfully developed a proof-of-principle measurement system for brake wear emissions from transient vehicle operation. The system shows good repeatability for stable particle metrics, such as non-volatile particle number (PN) from the solid particle counting system (SPCS), and allows for progression to a second phase of work where emissions differences between commercially available brake system components will be assessed.

Pollution from road vehicles enters the air environment from many sources. One such source could be if the vehicle is equipped with an auxiliary heater. They can be classified according to whether they work with diesel or gasoline and whether they heat water or air. The subject of our research series is an additional heating system that heats the air, the original fuel is gasoline. This device has been built up in a modern engine test bench, where the environmental parameters can be controlled. The length of the test cycle was chosen to be 30 min. The tested fuels were E10, E30, E100 and B7. A 30-min operating period has been chosen in the NORMAL operating mode of the device as a test cycle. The focus of the tests was particle number concentration and soot composition. The results of the particle number concentration showed that renewable fuel content significantly reduces the number concentration of the emitted particles (9.56 × 108 #/cycle for E10 vs. 1.65 × 108 #/cycle for E100), while B7 causes a significantly higher number of emissions than E10 (3.92 × 1010 #/cycle for B7). Based on the elemental analysis, most deposits are elemental carbon, but non-organic compounds are also present. Carbon (92.18 m/m% for E10), oxygen (6.34 m/m% for E10), fluorine (0.64 m/m% for E10), and zinc (0.56 m/m% for E10) have been found in the largest quantity of deposits taken form the combustion chamber.

Cooking food in water or soup, such as hot pot, is a widely used cooking method in China. This type of cooking requires no oil and cooks at a lower temperature, but that does not mean it produces fewer pollutants or is less harmful. There are few research studies on the emission characteristics and mechanisms of particulate matter emissions when eating hot pot (the boiling process), which leads to the unreasonable design of ventilation systems for this kind of catering. In this paper, the effects of boiling different ingredients (including noodles, potatoes, fish, tofu, meatballs, and pork) on particle number concentration emissions were studied. The particle number concentration and particle size distribution of PM with diameters of 0.3 μm and less, 0.3–0.5 μm and 0.5–1.0 μm (PM0.3, PM0.3–0.5 and PM0.5–1.0, respectively) were measured in an experimental chamber. The food type and shape showed very little change in the PM emission characteristics of boiling. When the boiling state was reached, the number concentration, particle size distribution, and arithmetic mean diameter of particles all fluctuated within 60 s. The emission characteristics of particles produced by boiling water and heating oil were compared. Heating oil produced more small particles, and boiling water released more large particles. Transient and steady methods were used to calculate the emission rate of particles, and the steady-state calculation has a high estimation of the emission rate. [ABSTRACT FROM AUTHOR]

The concentrations and behavior of nano particles (10–1000 nm) in Delhi, a densely populated megacity, in different seasons (winter, spring, summer, monsoon, and autumn) are examined, for the first time. The concentration of particles is classified into four different sizes as N nuc (10–30 nm, nucleation), N satk (30–50 nm, small Aitken), N latk (50–100 nm, large Aitken), and N acc (100–1000 nm, accumulation mode), and the total (10–1000 nm) particle number concentration (PNC) as N total. PNC ranges between 104 cm−3 and 106 cm−3 over Delhi during the year, and the highest concentration occurs in winter. Winter concentration is 2, 1.6 and 1.3 times higher than monsoon, summer, autumn and spring concentrations, respectively. N nuc , N satk , N latk and N acc and their respective contributions to total PNC exhibit significant seasonal variations. During winter N latk and N acc contribute more to total due to coagulation, with N acc alone contributing >40% to total PNC. N nuc , N satk, and N latk are higher in spring and summer during mid-day due to nucleation and/or ultrafine particle burst events. The direct primary emissions from engine exhaust produce a prominent double hump structure during morning and evening peak hours in winter and autumn. PNC and their contributions exhibit day-night variations as they are influenced by variations in emission sources and meteorological parameters (wind speed, relative humidity, temperature, solar radiation and boundary layer height) between day and night. Carbon monoxide correlates positively with N acc in all seasons (R2 ≥ 0.5) as fossil fuel emission is a predominant source for gases and particles in the study environment. These quantitative results on seasonal variations of nano particles and air pollutants together with the knowledge on seasonal variations in meteorological parameters and atmospheric dynamics provide a foundation which can positively contribute better to the urban planning and devising mitigation measures aimed at improving air quality and public health. • Seasonal nanoparticle number concentration (PNC) in Delhi varies from 104 to 106 cm−3. • Particles in nucleation mode contribute >30% to PNC in summer, spring and monsoon. • Accumulation mode particles contribute >35% to PNC in winter and autumn. • Higher relative humidity favors coagulation resulting in higher concentration of N acc. • Correlation between N acc and Carbon Monoxide is higher due to transport emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Long-term variability of PNC at multiple schools near two airports is investigated. • With a decreasing proximity to an airfield, the PNC concentrations increases. • The road-traffic emissions are important source of PNC measured at schools. • Regional NPF had an observable influence on UFP-nf and number concentration. • After airport closure, the PNC in surrounding areas decreased by 30 %. Studies revealed airports as a prominent source of ultrafine particles (UFP), which can disperse downwind to residential areas, raising health concerns. To expand our understanding of how air traffic-related emissions influence total particle number concentration (PNC) in the airport's surrounding areas, we conduct long-term assessment of airborne particulate exposure before and after relocation of air traffic from "Otto Lilienthal" Airport (TXL) to Berlin Brandenburg Airport "Willy Brandt" (BER) in Berlin, Germany. Here, we provide insights into the spatial–temporal variability of PNC measured in 16 schools recruited for Berlin-Brandenburg Air Study (BEAR). The results show that the average PNC in Berlin was 7900 ± 7000 cm−3, consistent with other European cities. The highest median PNC was recorded in spring (6700 cm−3) and the lowest in winter (5100 cm−3). PNC showed a bi-modal increase during morning and evening hours at most measurement sites due to road-traffic emissions. A comparison between measurements at the schools and fixed monitoring sites revealed good agreement at distances up to 5 km. A noticeable decline in this agreement occurred as the distance between measurement sites increased. After TXL was closed, PNC in surrounding areas decreased by 30 %. The opposite trend was not seen after BER was re-opened after the COVID-lock-down, as the air traffic has not reached the full capacity yet. The analysis of particle number size distribution data showed that UFP number fraction exhibit seasonal variations, with higher values in spring and autumn. This can be explained by nucleation events, which notably affected PNC. The presented findings will play a pivotal role in forthcoming source attribution and epidemiological investigations, offering a holistic understanding of airports' impact on airborne pollutant levels and their health implications. The study calls for further investigations of air-traffic-related physical–chemical pollutant properties in areas found further away (> 10 km) from airports. [ABSTRACT FROM AUTHOR]

Despite the potentially harmful effects on health and environmental impacts correlated with non-exhaust emissions (e.g., brake, tire and road wear and resuspension), but very limited environmental research studies have measured the contribution of vehicle non-exhaust emissions in real-world measurements and at different road segment types. Therefore, to fill this gap in academic literature, the main purpose of this study is to collect the knowledge base required to orient towards more sustainable mobility. During July 2019, continuous real-world measurements of non-exhaust particles (NEPs) were recorded over three different road segment types (urban, rural and motorway) in the city of Bron, near Lyon (France). Data were obtained using a native algorithm based on the GRIMM analyzer, series 1.108 Portable Aerosol Spectrometer. Results have confirmed abundant fine/coarse non-exhaust particle emissions which increase with the average vehicle speed and during sharp acceleration/deceleration manoeuvers. Motorway area has recorded the highest particle number concentrations as compared to urban and rural areas, which reaches 1.85 × 107 cm−3 due to increased vehicle speed, pavement materials and abrupt vehicle acceleration and deceleration maneuvers. In addition, the highest PM ratio was registered on motorway area and the lowest PM ratio appeared on urban road due to vehicle speed. It has been concluded that NEPs depended on the changes in driving conditions and road pavement type. [ABSTRACT FROM AUTHOR]

The smaller particles that dominate the particle number concentration (PNC) in the ambient air only contribute to a small percentage of particulate matter (PM) mass concentration although present in high particle number concentration. These small particles may be neglected upon assessing the health impacts of the PM. Hence, the knowledge on the particle number concentration size distribution deserves greater attention than the particulate mass concentration. This study investigates the measurement of the particle mass concentrations (PM2.5) and PNC of 0.27 μm < Dp < 4.50 μm during the southwest (SW), inter-monsoon (IM) and northeast (NE) monsoons in the industrial-residential airshed of Skudai, Johor Bahru, Malaysia. The PM2.5 mass concentrations and PNC were measured using a multi-channel GRIMM Environmental Dust Monitor (GRIMM EDM-SVC 365) equipped with a global positioning system. Diurnal variations, statistical analysis and regression plots were utilised from a six-month hourly data set to examine the patterns of the PNC size distributions and its relationships with the PM2.5 mass concentration. The overall mean PM2.5 mass concentration was 21.85 μg m−3, with the 24 h mean values of 26.80 μg m−3, 26.08 μg m−3 and 13.76 μg m−3 for the SW, IM and NE monsoons, respectively. It was found that the hourly mean of PNC was recorded at the highest concentration during the SW monsoon (373.20 # cm−3). The particles in the accumulation mode (Dp < 1.0 μm) were the prevalent form of the particle number concentration (94–98%). The scatter plots between the PM2.5 mass concentration and particle number size distribution showed that the PNC mode of 0.27 < Dp < 1.0 μm has the highest correlation value of r2 = 0.87 due to the emission from the anthropogenic activities. The results of this study highlight the importance of the PNC measurement in the seasonal variations of the PM2.5 pollution, indicating the significance of the regional-scale emission control actions in the local air quality management. [ABSTRACT FROM AUTHOR]

Background Exposure to fine and ultrafine particles from transport processes is a main consequence of emissions from engines, especially those with self-ignition. The particles released in these processes are a source of occupational and environmental particles exposure. The aim of this study was to assess the fine and nano-sized particles emission degree during work connected with transport and vehicle servicing. Material and Methods The tests were carried out at 3 workplaces of vehicles service and maintenance (a car repair workshop, a truck service hall, and a bus depot) during 1 work day in each of them. Measurements were performed using the following devices: DISCmini meters, GRIMM 1.109 optical counter and the DustTrak monitor. The number, surface area and mass concentration, and the number size distribution were analyzed. Results The mean number concentration (DISCmini) increased during the analyzed processes, ranging from 4×104 p/cm 3 to 8×104 p/cm 3 , and the highest concentration was found in the car repair workshop. The particles mean diameters during the processes ranged 31–47 nm, depending on the process. An increase in the surface area concentration value was observed in correlation with the particles number, and its highest concentration (198 m 2 /cm 3 ) was found during work in the car repair workshop. The number size distribution analysis (GRIMM 1.109) showed the maximum value of the number concentration for particles sized 60 nm. The mean mass concentrations increased during the tested processes by approx. 40–70%, as compared to the background. Conclusions According to the measurement results, all the workplaces under study constituted a source of an increase in all analyzed parameters characterizing emissions of nano-sized particles. Such working environment conditions can be harmful to the exposed workers; therefore, at such workplaces solutions for minimizing workers’ exposure, such as fume hoods or respiratory protection, should be used. Med Pr. 2021;72(5):489–500

Cyclopentanone from lignocelluloses is a promising renewable biofuel and can be used as diesel alternative fuel. Cyclopentanone has excellent fuel properties and high intramolecular oxygen content, which has the potential in promoting combustion and reducing emissions. In this study, the effects of blending cyclopentanone with diesel on the combustion and emission of common rail diesel engine were investigated. The novelty of this study is to figure out which blending ratio is the most promising for diesel engine. Cyclopentanone is blended with diesel with 10% and 20% ratio by vol., noted as C10 and C20, respectively. Double injection strategy (pre-injection and main-injection) was adopted in this study. Compared with pure diesel, blending cyclopentanone can prolong the ignition delay, increase the peak heat release rate and increase the peak in-cylinder temperature. The emission tests indicate that blending cyclopentanone can effectively reduce the particle number concentrations (PNC) and particle volume concentrations (PVC) compared to diesel. Further, the number geometric mean diameters (NGMD) of cyclopentanone diesel blend fuels are lower than those of diesel and the reduction increases with cyclopentanone blending ratio. However, a little increase in NOx emission is observed. With the increase of EGR ratio, the NOx emissions of all test fuels decrease obviously, the PNCs and PVCs of diesel and C10 increase. PNCs and PVCs of C20 almost remain unchanged when the EGR ratio is no higher than 8%. Consequently, with 8% EGR ratio, C20 has the best effect in reducing both particle and NOx emissions and it has great potential for application on diesel vehicles.

Airports contribute substantially to ultrafine particle (UFP;

Low-cost Particulate Matter (PM) sensors offer an excellent opportunity to improve our knowledge about this type of pollution. Their size and cost, which support multi-node network deployment, along with their temporal resolution, enable them to report fine spatio-temporal resolution for a given area. These sensors have known issues across performance metrics. Generally, the literature focuses on the PM mass concentration reported by these sensors, but some models of sensors also report Particle Number Concentrations (PNCs) segregated into different PM size ranges. In this study, eight units each of Alphasense OPC-R1, Plantower PMS5003 and Sensirion SPS30 have been exposed, under controlled conditions, to short-lived peaks of PM generated using two different combustion sources of PM, exposing the sensors’ to different particle size distributions to quantify and better understand the low-cost sensors performance across a range of relevant environmental ranges. The PNCs reported by the sensors were analysed to characterise sensor-reported particle size distribution, to determine whether sensor-reported PNCs can follow the transient variations of PM observed by the reference instruments and to determine the relative impact of different variables on the performances of the sensors. This study shows that the Alphasense OPC-R1 reported at least five size ranges independently from each other, that the Sensirion SPS30 reported two size ranges independently from each other and that all the size ranges reported by the Plantower PMS5003 were not independent of each other. It demonstrates that all sensors tested here could track the fine temporal variation of PNCs, that the Alphasense OPC-R1 could closely follow the variations of size distribution between the two sources of PM, and it shows that particle size distribution and composition are more impactful on sensor measurements than relative humidity.

Ultrafine particles (UFP), commonly expressed as particle number concentrations (PNC), have been associated with harm to human health yet are currently not regulated or routinely monitored in many places. This has limited the potential for studies of health effects of long-term exposure to UFP. The present study aims to understand the spatial and temporal variation in façade-level UFP exposures in Copenhagen, Denmark. We measured PNC at the façades of 27 residences across the city for approximately 72 h each in two campaigns and continuously at an urban background reference site for twelve consecutive months, using portable monitors (miniature diffusion size classifiers [DiSCminis]). We estimated annual means at the residential sites based on temporal adjustment using reference site data. Furthermore, we co-located the DiSCminis at a regulatory monitoring station on three occasions and compared daily means from our reference site to those from seven fixed-site monitoring stations throughout the city. Annual mean PNC at the reference site was 4715 (SD of hourly mean: 3001) pt/cm3, while annual means at 27 residences were slightly higher with a mean of 5201 pt/cm3 (SD: 807), ranging between 3735 and 6588 pt/cm3. The two individual adjusted campaign-specific means at 27 residential sites were weakly correlated (Spearman's correlation 0.11) and had an intra-class correlation coefficient of 0.06 (95%-confidence interval: −0.18, 0.28). Daily PNC at the reference site was highly correlated (R = 0.64–0.84) with PNC monitored at seven fixed-site stations throughout the city. We observed a seasonal trend at the reference site with the highest PNC in spring. Our measurement campaign revealed that façade-level PNC at residences in Copenhagen in 2021–2022 was relatively low with small spatial variability. The large variability in time suggests possibly longer and more frequent measurement campaigns to obtain more stable annual averages. Our study illustrates the challenges of UFP long-term exposure assessment. [Display omitted] • Annual mean façade-level particle number concentration (PNC) at residential sites was low and variable in time. • Little spatial variability of PNC was observed at residential sites throughout the city. • High temporal correlation was found across citywide locations (0.73–0.74). [ABSTRACT FROM AUTHOR]

Trees act as natural filters that mitigate roadside air pollution. However, the filtration impact of different tree arrangements on traffic pollutants with different particle diameters has rarely been analysed in real street canyon environments. To quantify how roadside tree arrangements impact pedestrian exposure to particle number concentrations (PNCs) of different diameters (0.25–32 μm), in situ field measurements were carried out in a boulevard-type street canyon in the city of Xi'an, China. This study analysed the experimental data of PNCs collected along segments of a pedestrian lane under four typical tree arrangements: open space without trees, a sparse-spaced tree arrangement, a medium-spaced tree arrangement, and a dense-spaced tree arrangement in a street canyon. Our results reveal that the effect of tree arrangement on PNCs depended on the particle diameter. In general, trees can significantly reduce coarse PNC (particles with diameters >2.5 μm) but not the fine PNC. Quantitative analysis showed that a medium-spaced tree arrangement, in which tree crowns are adjacent to each other but do not overlap, is the most capable of reducing PNC, followed by a sparse-spaced tree arrangement, while a the dense-spaced tree arrangement has the least impact. The attenuation effect of trees on the PNCs increased with increasing particle diameter. Moreover, the presence of trees altered the local microclimate, which also affected how exposure to PNCs changed. Our empirical findings further highlight the complexity of how trees affect particulate pollutants in street canyons and provide timely insights for enhancing tree-planning management in cities from the perspective of air quality improvement. [Display omitted] • The impact of tree arrangement on particle pollution depends on particle diameter. • Medium-spaced tree arrangement is the most effective at reducing coarse particles. • The particle number attenuation tends to increase with larger particle diameter. • Relative humidity is more correlated with fine particles than with coarse particles. [ABSTRACT FROM AUTHOR]

The present work aimed to assess the ambient levels of air pollution with particulate matter for both mass concentrations and number of particles for various fractions in Ploiesti city during the lockdown period determined by the COVID-19 pandemic (March–June 2020). The PM10 continuously monitored data was retrieved from four air quality automatic stations that are connected to the Romanian National Network for Monitoring Air Quality and located in the city. Because no other information was available for other more dangerous fractions, we used monitoring campaigns employing the Lighthouse 3016 IAQ particle counter near the locations of monitoring stations assessing size-segregated mass fraction concentrations (PM0.5, PM1, PM2.5, PM5, PM10, and TPM) and particle number concentration (differential Δ) range between 0.3 and 10 microns during the specified timeline between 8.00 and 11.00 a.m., which were considered the morning rush hours interval. Interpolation maps estimating the spatial distribution of the mass concentrations of various PM fractions and particle number concentration were drawn using the IDW algorithm in ArcGIS 10.8.2. Regarding the particle count of 0.5 microns during the lockdown, the smallest number was recorded when the restriction of citizens’ movement was declared (24 March 2020), which was 5.8-times lower (17,301.3 particles/cm3) compared to a common day outside the lockdown period (100,047.3 particles/cm3). Similar results were observed for other particle sizes. Regarding the spatial distribution of the mass concentrations, the smaller fractions were higher in the middle of the city and west (PM0.5, PM1, and PM2.5) while the PM10 was more concentrated in the west. These are strongly related to traffic patterns. The analysis is useful to establish the impact of PM and the assessment of urban exposure and better air quality planning. Long-term exposure to PM in conjunction with other dangerous air pollutants in urban aerosols of Ploiesti can lead to potential adverse effects on the population, especially for residents located in the most impacted areas.

The school environment is crucial for the child's health and well-being. On the other hand, the data about the role of school's aerosol pollution on the etiology of chronic non-communicable diseases remain scarce. This study aims to evaluate the level of indoor aerosol pollution in primary schools and its relation to the incidence of doctor's diagnosed asthma among younger school-age children. The cross-sectional study was carried out in 11 primary schools of Vilnius during 1 year of education from autumn 2017 to spring 2018. Particle number (PNC) and mass (PMC) concentrations in the size range of 0.3–10 µm were measured using an Optical Particle Sizer (OPS, TSI model 3330). The annual incidence of doctor's diagnosed asthma in each school was calculated retrospectively from the data of medical records. The total number of 6–11 years old children who participated in the study was 3638. The incidence of asthma per school ranged from 1.8 to 6.0%. Mean indoor air pollution based on measurements in classrooms during the lessons was calculated for each school. Levels of PNC and PMC in schools ranged between 33.0 and 168.0 particles/cm3 and 1.7–6.8 µg/m3, respectively. There was a statistically significant correlation between the incidence of asthma and PNC as well as asthma and PMC in the particle size range of 0.3–1 µm (r = 0.66, p = 0.028) and (r = 0.71, p = 0.017) respectively. No significant correlation was found between asthma incidence and indoor air pollution in the particle size range of 0.3–2.5 and 0.3–10 µm. Conclusion: We concluded that the number and mass concentrations of indoor air aerosol pollution in primary schools in the particle size range of 0.3–1 µm are primarily associated with the incidence of doctor's diagnosed asthma among younger school-age children. What is Known: • Both indoor and outdoor aerosol pollution is associated with bronchial asthma in children. What is New: • The incidence of bronchial asthma among younger school age children is related to indoor air quality in primary schools. • Aerosol pollutants in the size range of 0.3–1 µm in contrast to larger size range particles can play major role in the etiology of bronchial asthma in children. [ABSTRACT FROM AUTHOR]

A method based on single particle inductively coupled plasma mass spectrometry (spICP-MS) was established to accurately quantify the particle number concentration of polydisperse gold nanoparticles (AuNPs) sample with two sizes of 30 nm and 60 nm. The effect of carrier gas flow rate and sampling depth on the size resolution, as well as the effect of acquisition time and dwell time on the measured particle number concentration were investigated. The results showed that the optimized carrier gas flow rate could significantly improve the size resolution, while the impact of the sampling depth was relatively negligible. The highest size resolution was obtained when the carrier gas flow rate was 0.8 L/min and the sampling depth was 9 mm, and the extended acquisition time could effectively reduce the relative standard deviation (RSD) of the result. When the acquisition time was increased to 180 s, the particle number concentration of 30 nm and 60 nm AuNPs in the polydisperse sample was lower than 5% (n=3). When the dwell time was selected as 0.1 ms, the result was consistent with the prepared value, and the particulate and ionic Au could be entirely separated. Under the optimized conditions, the detection limits of particle size and particle number concentration were 10 nm and 49 NPs/g, respectively. The established method was employed successfully to quantify the polydisperse sample with different mixing ratios, and the results were consistent with the standard values, proving the reliability of the method. Finally, this method was successfully applied to tap water, spring water and lake water, and the recovery rates of the three water samples were satisfied in the range of 80%-120%. The method has the advantages of high size resolution, better precision and low ion interference, which is an accurate method for the quantification of polydisperse nanoparticles in the environmental matrix. [ABSTRACT FROM AUTHOR]

20 kinds of electrically heated cigarettes from 5 brands in the market were collected to characterize and compare the physical properties (number concentration, count median diameter and volume concentration) of total and puff-by-puff released aerosol. The results showed that the particle number concentration of the total aerosol released from the electrically heated cigarette was mainly in the order of 109/cm³, and the particle volume concentration was in the order of 105 μm³/cm³. The particle size distribution profiles of aerosol were unimodal or bimodal, and the count median diameter was mainly in the range of 30~60 nm. There were obvious differences in physical properties of total and puff-by-puff release of the aerosol from different brands of electrically heated cigarettes. The particle number concentration, count median diameter and volume concentration of the aerosol puff-by-puff released from the electrically heated cigarettes showed a certain degree of instability. [ABSTRACT FROM AUTHOR]

Particle matter is one of the criteria air pollutants which have the most considerable effect on human health in cities. Its legislation and regulation are mostly based on mass. We showed here that the total number of particles and the particle number concentrations in different size fractions seem to be efficient quantities for air quality monitoring in urbanized areas. Particle number concentration (N) measurements were realized in Budapest, Hungary, for nine full measurements years between 2008 and 2021. The datasets were complemented by meteorological data and concentrations of criteria air pollutants. The annual medians of N were approximately 9 × 103 cm−3. Their time trends and diurnal variations were similar to other large continental European cities. The main sources of N are vehicle road traffic and atmospheric new aerosol particle formation (NPF) and consecutive growth events. The latter process is usually regional, so it appears to be better assessible for contribution quantification than mass concentration. It is demonstrated that the relative occurrence frequency of NPF was considerable, and its annual mean was around 20%. NPF events increased the contribution of ultrafine (UF < 100 nm) particles with respect to the regional particle numbers by 12% and 37% in the city center and in the near-city background, respectively. The pre-existing UF concentrations were doubled on the NPF event days. [ABSTRACT FROM AUTHOR]

Vehicle occupants spend prolonged durations inside the cabin due to longer commute or congested road networks. The poor in-cabin air quality and prolonged travel duration contribute a significant fraction to occupant's daily exposure levels. The intrusion of outside air pollutants inside vehicle through ventilation system and cabin leakages are recognized as dominant factors that influence the in-transit air quality. In the present study, mobile campaign was conducted from regular passenger cars to investigate the impact of vehicle characteristics, ventilation settings, fan strength, and driving speed over in-cabin particle number concentration (PNC) and air exchange rates (AERs) under realistic driving conditions. Under outside air (OA) mode, outdoor ambient air is drawn inside the vehicle cabin whereas, under recirculation (RC) mode, in-cabin air is recirculated by ventilation fan. The average in-cabin total PNC measured under OA and RC modes are 6.61E + 07 # m−3 and 2.02E + 07 # m−3 respectively. The AERs estimated under realistic driving conditions with OA and RC modes had mean (median) values of 17.44 (12.65) h−1 and 8.24 (6.99) h−1 respectively. The AERs potential influencing parameters (vehicle age, mileage, speed, cabin volume, and fan operating strength) were measured for each trip. A Generalized Estimating Equation (GEE) model was developed and outcomes revealed that vehicle age and cabin volume are statistically significant factors in determining the AERs under OA and RC modes respectively. However, vehicle speed and fan strength variables were positively associated with AERs but not statistically significant under OA mode. Highlights: Two ventilation modes were studied to assess their impact on passenger car in-cabin PNC. In-cabin total PNC reduced by 69% while commuting under RC ventilation mode. AERs vary significantly with ventilation modes and fan strength under realistic driving conditions. Shifting to highest fan strength increased the AERs by 2.73 times under OA mode. [ABSTRACT FROM AUTHOR]

In this study, isopropanol and n-pentanol are blended in diesel with 20% ratio by volume, named D80IP20 and D80NP20. Their combustion and emission performances were compared with diesel on a four cylinder common rail diesel engine under pilot plus main injection strategy. The pilot injection duration decreases and the main injection duration increases with engine loads. For test fuels, the starts of pilot and main injection and the durations of pilot injection are remained unchanged in each engine operation. D80IP20 has the longest ignition delay due to the lowest cetane number and the shortest combustion duration due to the highest fuel oxygen. However, the peak combustion temperature of D80IP20 is lower than that of D80NP20 under double injection strategy. Compared to diesel, both D80IP20 and D80NP20 obviously reduce the particle number concentrations (PNCs) and the particle volume concentrations (PVCs), while increase the NOx emissions. D80IP20 has the lowest PNCs and PVCs and its number geometric mean diameter (NGMD) and volume geometric mean diameter (VGMD) are the lowest among the three fuels. D80IP20 has higher NOx emission than diesel, but lower than D80NP20 due to lower PCT. Further, D80IP20 with 10% EGR can achieve the simultaneous reduction for NOx emission and PNCs at low and high loads compared to diesel without EGR. Results indicate that blending isopropanol in diesel has better effects in combustion improvement and emission control and is more suitable than n-pentanol under pilot plus main injection strategy.

The prediction of the particle number concentration and liquid/ice water content of cloud is significant for many aspects of atmospheric science. However, given the uncertainties in the initial and boundary conditions and imperfections of microphysical schemes, the accurate prediction of these microphysical properties of cloud is still a big challenge. The ensemble approach may be a viable way to reduce forecast uncertainties. In this paper, a large-scale stratiform cloud precipitation process is studied by comparing results of a 10-member ensemble forecast model with aircraft observation data. By means of the ensemble average, the prediction of bulk parameters such as liquid water content and ice water content can be improved in comparison with the control member, but the particle number concentrations are still one to two orders of magnitude less than those from observations. Intercomparison of raindrop size spectra reveals a big distinction between observations and predictions for particles with a diameter less than 1000 μm.

Cooking food in water or soup, such as hot pot, is a widely used cooking method in China. This type of cooking requires no oil and cooks at a lower temperature, but that does not mean it produces fewer pollutants or is less harmful. There are few research studies on the emission characteristics and mechanisms of particulate matter emissions when eating hot pot (the boiling process), which leads to the unreasonable design of ventilation systems for this kind of catering. In this paper, the effects of boiling different ingredients (including noodles, potatoes, fish, tofu, meatballs, and pork) on particle number concentration emissions were studied. The particle number concentration and particle size distribution of PM with diameters of 0.3 μm and less, 0.3–0.5 μm and 0.5–1.0 μm (PM0.3, PM0.3–0.5 and PM0.5–1.0, respectively) were measured in an experimental chamber. The food type and shape showed very little change in the PM emission characteristics of boiling. When the boiling state was reached, the number concentration, particle size distribution, and arithmetic mean diameter of particles all fluctuated within 60 s. The emission characteristics of particles produced by boiling water and heating oil were compared. Heating oil produced more small particles, and boiling water released more large particles. Transient and steady methods were used to calculate the emission rate of particles, and the steady-state calculation has a high estimation of the emission rate.

Highway toll booth workers have been reported to be at an increased risk of occupational lung cancer. Moreover, insufficient studies have been performed on exposure assessment of workers at highway toll booths. Elemental carbon (EC), black carbon (BC), and respirable crystalline silica (RCS) concentrations were measured at highway toll booths in Gyeongsangbuk-do (Republic of Korea). The particle number (PN) concentration and size distribution of ultrafine particle were measured using three SMPS devices. The average concentration of the EC inside the booth was 3.3 µg/m3, with the maximum being 5.8 µg/m3. The concentrations of EC were highest for booths that operated exclusively for trucks. The average PN concentration inside the booth was 3.54 × 104 cm-3, approximately 5-fold higher than the reference indoor background. The average BC concentration in the booths were approximately 8 µg/m3, and the instantaneous peak concentration was 271 µg/m3. The RCS was below the detection limit in all samples. This study revealed that toll workers were most frequently exposed to diesel engine particle less than 100 nm, with an extremely high respiratory deposition rate. Therefore, a respiratory protection program is necessary to safeguard these workers against vehicle-related pollutants. [ABSTRACT FROM AUTHOR]

Background: Air pollution in subway environments is a growing concern as it often exceeds WHO recommendations for indoor air quality. Ultrafine particles (UFP), for which there is still no regulation nor a standardized exposure monitoring method, are the strongest contributor to this pollution when the number concentration is used as exposure metric. Objectives: We aimed to assess the real-time UFP number concentration in the personal breathing zone (PBZ) of three types of underground Parisian subway professionals and analyze it using a novel Bayesian spline approach. Consecutively, we investigated the effect of job, week day, subway station, worker location, and some further events on UFP number concentrations. Methods: The data collection procedure originated from a longitudinal study and lasted for a total duration of 6 weeks (from October 7 to November 15, 2019, i.e. two weeks per type of subway professionals). Time-series were built from the real-time particle number concentration (PNC) measured in the PBZ of professionals during their work-shifts. Complementarily, contextual information expressed as Station, Environment, and Event variables were extracted from activity logbooks completed for every work-shift. A Bayesian spline approach was applied to model the PNC within a Bayesian framework as a function of the mentioned contextual information. Results: Overall, the Bayesian spline method suited a real-time personal PNC data modeling approach. The model enabled estimating the differences in UFP exposure between subway professionals, stations, and various locations. Our results suggest a higher PNC closer to the subway tracks, with the highest PNC on subway station platforms. Studied event and week day variables had a lesser influence. Conclusion: It was shown that the Bayesian spline method is suitable to investigate individual exposure to UFP in underground subway settings. This method is informative for better documenting the magnitude and variability of UFP exposure, and for understanding the determinants in view of further regulation and control of this exposure.

To better understand the responses of particle number concentrations (PNCs) and new particle formation (NPF) to the largely reduced air pollutant emissions in urban atmospheres, we investigated the particle number size distributions in Qingdao, a coastal megacity in northern China, during two separate periods, 2010–2012 and 2016–2018. The results show only an average of 5% decrease in the total PNCs in 2016–2018 relative to 2010–2012, although the PM2.5 mass concentration decreased by over 40%. Nucleation‐mode PNCs decreased by 20%, which is attributable to reductions in primary emissions from on‐road vehicles and secondary sources. Unexpectedly, the accumulation‐mode PNCs increased by 11% in 2016–2018 relative to 2010–2012. The SO2 concentrations strongly decreased by ∼60%, and the NPF frequencies slightly decreased from 34% in 2010–2012 to 25% in 2016–2018. However, there were no significant changes in the apparent new particle formation rate (FR) or net maximum increase in nucleation‐mode PNCs (NMINP). The increased concentrations of other precursors may substantially negate the effect of SO2 reduction, leading to the invariant FR and NMINP. The maximum sizes of grown new particles decreased by 50%; combined with the decreased NPF frequency, the contribution of grown new particles to accumulation‐mode PNCs expectedly decreased in 2016–2018 relative to 2010–2012. Alternatively, the increased accumulation‐mode PNCs in 2016–2018 mainly attribute to the enhanced primary combustion emissions excluding on‐road vehicle emissions. The increase in accumulation‐mode PNCs in 2016–2018 provides insights on the inter‐annual variation in satellite‐based cloud properties, which appeared insensitive to the large decrease in satellite‐based aerosol optical depth. Key Points: Total particle number concentrations (PNCs) decreased by 5% in 2016–2018 relative to 2010–2012, despite the PM2.5 decreased by over 40%In 2016–2018, nucleation‐mode PNCs decreased by 20% relative to 2010–2012, whereas accumulation‐mode PNCs increased by 11%Maximum sizes of grown new particles were reduced by 50%, leading to a decreased contribution of new particles to accumulation mode PNCs [ABSTRACT FROM AUTHOR]

Background The aim of the presented work was the assessment of occupational exposure to nanoparticles and ultrafine particles during selected processes of using construction materials. Material and Methods The tests were carried out at the following workplaces: abrasion and pouring of 2 products – nanomortar and nanocrete. Measurements were carried out using the following devices: DiSCmini measurer, GRIMM 1.109 optical counter and DustTrak monitor. The number, surface area, mass concentration and size distribution were analyzed. Results DiSCmini measurements showed that the mean number concentration of particles during the analyzed processes ranged of 1.4×104–1.0×105 particles/cm 3 , and the highest one was during nanomortar abrasion. The mean particles diameters during the processes ranged 28.9−47.1 nm depending on the process. An increase in the average value of the particles surface area concentration was observed, the largest value was found during nanomortar abrasion – 255.9 μm 2 /cm 3 . The size distributions analysis (GRIMM 1.109) showed that the dimensions of particles released in the processes had a wide range, however the majority of particles were in the range of 60–145 nm. The analysis of the mass concentration (DustTrak) showed that the fraction of particles < 1 μm was minimum 50% of the total analyzed particles during the process. Conclusions During the processes under study, a large increase in all analyzed parameters describing the emission of ultrafine particles was observed. This allows to conclude that the smallest particles emitted during the using of nanostructures containing construction materials may be a potential health risk factor for people exposed to these materials. Med Pr. 2019;70(1):67–88