Coarse Particle Concentrations Research Articles

A Development of a Coarse Particle Concentration Measurement System Using a Crystal-Based Sensor and a Dust Sensor for Air Quality Measurement

QCM or quartz crystal microbalance is a non static crystal that can be used as a mass sensor. As a piezoelectric crystal, a QCM generates an electrical signal with a specific frequency. The frequency change can be utilized as a frequency counter in a mass measurement system. This study aims to develop a coarse particle sensor system using a QCM and an oscillator circuit. In line with this, this study uses an oscillator circuit and a QCM for a sensor development. Thus, the frequency measurement of the QCM contains an oscillator and a signal conditioner connected to a microcontroller. For this purpose, an Arduino Nano was used as the signal processing, while a QCM was used as a coarse particle sensor and compared to a digital dust sensor (Winsen ZH03). The sensor system was evaluated using a fixed-type crystal connected to an oscillator: 2.5 MHz - 7.2 MHz. Arduino Nano processed the frequency signal generated by the developed oscillator. The results show that the sensor system has a stable output signal compared to the comparator. There is a linear correlation between the frequency measured by the system and the oscilloscope (99.73%). It can be concluded that the sensor system can measure coarse particle concentrations from 32-620 ug/cm3 (frequencies from 2 MHz to 7.2 MHz) with a response time of 1 second. The system has an accuracy of 99% and a resolution of 1 Hz.

The influence of cold seepage on the grain size and geochemistry of sediments from the Laptev Sea shelf

The East Siberian Arctic shelf is renowned for its active methane-rich fluid seeps, confirmed by numerous gas flares in the water column and direct observations of methane release from the seafloor. These cold-seep sites serve as natural laboratories for studying the impact of methane seepage on early diagenesis, authigenic mineral formation, and the geochemical cycles of carbon, sulfur, and other elements. This study examines the grain size and chemical composition of two sediment types from the Laptev Sea shelf: cold-seep sediments influenced by sulfate-driven anaerobic methane oxidation, and unaffected “seep-free” sediments (i.e., control site). High methane concentrations (up to 649 μM/L) in the surface layer of sediments indicate that the sulfate–methane transition zone is found close to the sediment–water interface approximately 5–6 cm below the seabed. At the cold-seep site, thin layers containing up to 40% sand fraction were discovered among the fine-grained sediments. We infer that upward-migrating fluids may contribute to the remobilization of the fine fraction, resulting in concentration of coarse particles. Cold-seep sediments are characterized by molybdenum (Mo) enrichment compared to the lithological background, although one “seep-free” core exhibits evidence of authigenic Mo deposition. The Mo concentration (up to 16.8 ppm) indicates that enrichment occurs under sulfidic conditions restricted to pore water, which are caused by anaerobic methane oxidation. The high Mo concentration in one “seep-free” core likely implies past cold-seep activity. A general Mo–U covariation indicates that the molybdenum enrichment in cold-seep sediments from the Laptev Sea outer shelf is controlled by a weak particulate shuttle process.

Air quality and characterization of synoptic circulation weather patterns in a South American city from Argentina

The potential cause-effect relationship between synoptic meteorological conditions and levels of criteria air pollutants, including CO, NO2, O3, PM10, PM2.5 and SO2, in Bahia Blanca, Argentina, was assessed for the period of 2018–2019. Daily back-trajectories and global meteorological data fields were employed to characterize the primary transport paths of air masses reaching the study site, and to identify the synoptic meteorological patterns responsible for these atmospheric circulations. Time series of surface-level meteorological parameters and midday mixing layer height were collected to examine the impact of the synoptic meteorological patterns on local meteorology. Furthermore, the NAAPS global aerosol model was utilized to identify days when contributions from long-range transport processes, such as dust and/or biomass burning smoke, impacted air quality. By applying this methodology, it was determined that the air masses coming from the N, NW and W regions significantly contributed to increased mean concentrations of coarse particles in this area through long-range transport events involving dust and smoke. Indeed, the high average levels of PM10 recorded in 2018–2019 (annual mean values of 47 and 52 μg/m3, respectively) represent the main air quality concern in Bahía Blanca. Moreover, PM10, PM2.5 and NO2 emissions should be reduced in order to meet recommended air quality guidelines. On the other hand, the results from this study suggest that the sources and meteorological processes leading to the increase in the concentrations of CO and SO2 have a local-regional origin, although these air pollutants did not reach high values probably as a consequence of the strong wind speed registered in this region during any synoptic meteorological pattern.

Criteria air pollutants and diabetes mortality classified by different subtypes and complications: A nationwide, case-crossover study

The associations between air pollution and diabetes mortality of different subtypes and complications were largely unclear. We performed an individual-level, time-stratified case-crossover study among over 0.9 million diabetes deaths from all administrative regions of Chinese mainland during 2013–2019. Daily concentrations of fine particles (PM2.5), coarse particles (PM2.5–10), nitrogen dioxide (NO2) and ozone (O3) were obtained for each decedent using high-resolution prediction models. Conditional logistic regression models were utilized to analyze the data. Each interquartile range increment in PM2.5, PM2.5–10, NO2 and O3 concentrations on lag 0–2 d increased the risks of overall diabetes mortality by 2.81 %, 1.92 %, 3.96 % and 2.15 %, respectively. Type 2 diabetes had stronger associations with air pollution than type 1 diabetes. Air pollutants were associated with diabetic ketoacidosis and diabetic nephropathy, but not other complications. The exposure-response curves were approximately linear with a plateau at higher concentrations of PM2.5, PM2.5–10, and NO2, while the associations for O3 appear to be statistically significant beyond 60 μg/m3. This nationwide study reinforces the evidence of higher risks of acute diabetic events following short-term air pollution exposure. We identified differential effects of air pollutants on various subtypes and complications of diabetes, which require further mechanistic investigations.

Background concentrations of airborne, culturable fungi and dust particles in urban, rural and mountain regions

Geographic location and meteorological factors can affect the content of bioaerosol concentrations. This study was conducted to determine the natural background concentrations of culturable fungal spores and dust particles in three different geographical areas. Focus was given to the dominant airborne genera Cladosporium, Penicillium, Aspergillus and the species Aspergillus fumigatus. The influence of weather conditions on the microorganism concentrations in urban, rural and mountain regions were examined. Possible correlations between particle counts and culturable fungal spore concentrations were investigated.125 measurements of the air were conducted using the air sampler MAS–100NT® and the particle counter Alphasense OPC–N3. The analyses of the collected samples were based on culture methods using different media.The highest median of fungal spore concentrations was detected in the urban region and was of 2.0 × 103 CFU/m3 for xerophilic fungi and 1.7 × 103 CFU/m3 for the genus Cladosporium. The concentrations of fine and coarse particles in rural and urban regions were the highest of 1.9 × 107 pa/m3 and 1.3 × 107 pa/m3, respectively. Little cloud cover and slight wind had a positive influence on the concentration of fungal spores. Furthermore, correlations were observed between air temperature and the concentrations of xerophilic fungi as well as the genera Cladosporium. In contrast, relative humidity correlated negatively with total fungi and Cladosporium and no correlation was found with the other fungi. For the region of Styria in summer and early autumn, the natural background concentration for xerophilic fungi ranged between 3.5 × 102 and 4.7 × 103 CFU/m3 air. No significant differences were detected between the fungal spore concentrations in urban, rural and mountainous regions.The data of this study could be used as a reference to compare the natural background concentrations of airborne culturable fungi in further studies concerning air quality assessment.

ПОЛИЦИКЛИЧЕСКИЕ АРОМАТИЧЕСКИЕ УГЛЕВОДОРОДЫ И ЧАСТИЦЫ PM10, PM2,5, PM1,0 В АТМОСФЕРЕ ЮЖНОГО ПРИБАЙКАЛЬЯ

The study presents the data on concentrations of polycyclic aromatic hydrocarbons (PAHs), coarse (PM10, PM2.5) and submicron (PM1.0) particles in the atmosphere over the southern Baikal region at two monitoring stations (urban (Irkutsk) and rural (Listvyanka village)) in 2019-2022. Seasonal dynamics and high correlations between their concentrations are revealed. It was found out that PAHs are mainly sorbed on coarse particles in the atmosphere over Irkutsk and on submicron particles in Listvyanka. The total concentration of 21 PAHs varied at the stations from 1-3 ng/m3 in summer to 35-50 ng/m3 in winter, with an average annual value approximately 20 ng/m3. High concentrations in all seasons were determined for fluoranthene, pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, and phenanthrene. The calculated equivalent of aerosol toxicity in the atmosphere over Irkutsk increased from summer to winter with a growing contribution of benzo[a]pyrene exceeding maximum permissible concentration (MPC) by 8 times. The mass concentration during the year varied from 13 to 180 µg/m3 for PM10, from 4 to 121 µg/m3 for PM2.5, from 4 to 118 µg/m3 for PM1.0. Exceeding the MPC for PM2.5 by 1.1-3.4 times was recorded in Irkutsk from November to May. Diagnostic ratios of PAHs and the factor analysis identified the main sources of air pollution by this class of compounds over the southern Baikal region, which are combustion of coal, liquid fuel, and firewood, and also motor transport emissions.

Indoor Particle's Pollution in Bucharest, Romania.

Air pollution risk factor on human health was surpassed only by high blood pressure, tobacco use and poor diet. Total number of deaths due to air pollution worldwide was estimated to 6.67 million people in 2019. In the European Union, 97% of the urban population is exposed to levels of fine particulate matter above the latest guideline levels set by the World Health Organization. Air pollution accounts for 20% of newborn deaths worldwide, most related to complications of low birth weight and preterm birth. Low birth weight and preterm birth are responsible for 1.8 million deaths worldwide. Bucharest is the capital city of Romania and one of the most polluted cities in Europe, ranking in the 9th position out of 96 of the top cities from Europe and in the 4th position out of 32 of the top cities in Eastern Europe, data from June 2022. The aim of this study was to measure the real time level of indoor particulate pollution levels in different indoor environments from Bucharest, during the pandemic period. The PM2.5/PM10 ratio and its rate of change were also determined for the measured data. The PM2.5/PM10 ratio and its rate of change were also calculated based on the measurement data. The PM2.5/PM10 ratio showed an upward trend on weekends compared to weekdays, suggesting a relationship with outdoor PM where leisure activities and traffic infiltrated the indoors. The fluctuation range of the PM2.5/PM10 ratio was 0.44~0.95, and low measured values were detected on weekdays. Of the seasons, the proportion of particulate in autumn and its rate of change tended to be higher than in summer. It was suggested that outdoor air may have permeated the room. In addition, the relationship was considered, such as it is a holiday period, there are few rainy days, the concentration of coarse particles is high, and the number of residents in the city decreases. When it comes to indoor air quality, the higher this ratio, the more serious the air pollution. PM10 concentrations decreased by 29.1% in the absence of human activity and increased by 35.1% in the presence of humans. PM2.5 concentration decreased by 30.3% without human activity and increased by 3.1% with the presence of humans. Certain trends were suggested for the resumption of human activity and an increase in PM2.5 concentrations. The average relative difference between October 2021, a pandemic period, and October 2022, a post pandemic period, was 64% for PM10 and 47% for PM2.5. The pandemic period brought a significantly better indoor air quality from the particulate pollution point of view.

Time Variations in Submicron and Coarse Particle Concentrations in the Surface Air Layer at the Aerosol Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (2000–2020)

Time Variations in Submicron and Coarse Particle Concentrations in the Surface Air Layer at the Aerosol Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (2000–2020)

Factors affecting particle number size distributions at a suburban and a rural site at the Anatolian Plateau

In this work, number size distributions of particles between 0.2 and 34 μm were measured with a laser spectrometer. Temporal and spatial variability in size distributions were investigated. Measurements were carried out at two stations; the Mediterranean coast of Turkey (Marmaris) and central Anatolia (Ankara). PM1, PM2.5, and PM10 mass concentrations were measured. Flow climatology indicated that air masses spent more time in the south of Mediterranean basin in winter and in the North of the basin during summer months. Median PM10 concentrations measured in Marmaris and Ankara stations were 17 and 38 μg m−3, respectively. North African dust transport was not the main PM10 source in the suburban station, but it was significant in the rural station. The median PM2.5 concentration was higher at Ankara due to anthropogenic emissions which was not observed in Marmaris. Median PM1 concentrations were comparable in both stations. 90–95% of the particles were between 0.26 and 0.42 μm size ranges. Coarse particle concentrations were higher at the suburban station, whereas fine particles were higher at the rural station. Concentrations depicted a well-defined seasonal pattern in the rural station, with higher concentrations in summer season. Although concentrations of PM size fractions were also higher in the summer season in Ankara station, seasonal differences were not as well-defined as in the rural station. PM1 and PM2.5 concentrations did not show any difference between weekends and weekdays, but PM10 concentrations, particularly the 2.5 μm < D < 10 μm, were higher on weekdays due to contribution of resuspended road dust.

Correlation analyses between downward longwave radiation particulate matters, aerosol optical depth, and metrological variables under non-dusty and cloudless conditions

This study used downward longwave (LW) radiation measurements, air temperature (T), particulate matter (PM) concentrations of fine (PM 2.5) and coarse (PM10) particles, aerosol optical depth (AOD), wind speed (WS), and precipitable water vapor (PWV) data from Riyadh, an arid site in central Saudi Arabia, between 2014 and 2019 to characterize their variations and investigate the influence of these variables on the measured downward LW radiation under non-dusty, clear sky conditions. The LW radiation and air temperature, it was found, attain their maximum in summer and minimum in winter. Conversely, the PM mean concentrations and AOD showed their maximum in spring and minimum in winter. PWV features an increasing trend during spring, summer, and fall, whereas it features a decreasing trend during the winter. The monthly variation of WS shows low monthly values during fall and winter and considerably higher monthly mean variation during spring and summer. Apart from wind speed, which does not affect the LW radiation, correlation analyses demonstrated that the LW correlates positively with the remainder of the considered variables. The strength and degree of association between the LW radiation and these variables differ from one variable to another, with air temperature having the strongest correlation (correlation coefficient = 0.98) with the LW radiation, followed by the AOD (correlation coefficient = 0.69), with a correlation coefficient of 0.36 with the PWV. Similarly, the relationships between the LW radiation and both PM10 and PM2.5 had the same correlation coefficient of 0.32. The effect of the meteorological variables (mainly air temperature, relative humidity, and wind speed) on the PM concentrations was investigated using the regression analyses. The results showed a significant positive relationship with air temperature and wind speed and a negative relationship with RH.

Size Distributions of Inhalable Particulate Matter and Particle-bound Heavy Metals and Their Potential Occupational Health Risk Related to Informal E-waste Recycling in Thailand

Concentrations and size distributions of atmospheric particulates and particulate-bound heavy metals in different inhalable fractions were studied in working areas during manual dismantling, thermal cutting and cable sheath burning activities. The particulate samples were collected on quartz fiber filters using an eight-stage cascade impactor with flow rate of 28.3 l min-1. Mass concentrations of the particles were measured in each size fraction. Heavy metals bound on the particles were extracted with acid digestion and then analyzed using Atomic Absorption Spectrophotometer. Risk assessment of worker exposure to the particles was determined. The results indicated that the concentrations of ultrafine (dae &lt; 0.43 μm), fine (0.43 &lt; dae &lt; 2.1 μm) and coarse (2.1 &lt; dae &lt; 10 μm) particles were in the ranges of 14.49-62.04, 57.51-120.26 and 153.26–646.99 μg m−3 during manual dismantling, 363.41-1,011.95, 2,105.40-4,899.11 and 1,698.54-7,075.61 μg m−3 during thermal cutting and 364.73-1,694.72, 1,953.33-4,431.41 and 1,385.97-6,126.13 μg m−3 during cable sheath burning, respectively. The concentrations of PM2.1 and PM10 released from these activities did not exceed the OSHA PEL threshold limits. Heavy metals adsorbed on the particles (Fe, Cr, Zn, Cu, Pb, Mn) detected during manual dismantling did not exceed the TWA standard. Concentrations of Cr and Pb during cable sheath burning highly exceeded the standards whereas Pb concentrations during thermal cutting slightly exceeded the standard. The heavy metals released from these recycling activities were more enriched on coarse mode than fine mode. Inhalation exposure to Cr, Pb and Mn posed a potential health risk to the workers.

Air pollution exposure assessment simulation of babies in a bike trailer and implication for mitigation measures

Young children are a vulnerable population cohort. They receive higher exposure to particulate matter than adults in outdoor roadside environments, necessitating research on an unexplored area of exposure to young children in electric bike trailers. We simulated the exposure profiles of an adult cyclist and young children sitting in a bike-trailer attached to it for multiple air pollutants – particulate matter ≤10µm in aerodynamic diameter (PM10), ≤2.5µm (PM2.5; fine particles), ≤1µm (PM1), BC, and CO2 – during the school run in the morning and afternoon hours. We assessed the differences in their exposure concentrations and analysed the impact of trailer covers and COVID-19 lockdown restrictions via simultaneous measurements under six settings forming three scenarios: (i) bike-trailer versus adult cyclist height; (ii) bike-trailer with and without the cover; and (iii) exposure during the lockdown and eased-lockdown periods. We carried out a total of 82 single runs covering a length of 176 km. These runs were repeated on a 2.1 km long predefined route between an origin (University campus) and destination (a local school) to simulate morning drop-off (08:00-10:00h; local time) and afternoon pick-up (15:00-17:00h) times of school children. Substantial variability was observed in concentrations of measured pollutants within each run (e.g., up to 97% for BC) and between different runs (e.g., ∼93% for PM2.5 during morning versus afternoon) in bike-trailer. Compared with cyclist height, the average bike-trailer concentration of coarse (fine) particles was higher by up to 14% (2.5%) and 18% (14%) during morning and afternoon runs, respectively. The lockdown restrictions when schools were closed led to a reduction in bike-trailer PM2.5 concentrations by up to 91% compared with eased lockdown period when schools re-opened in March 2021. Trailer covers led up to 50% (fine particles) and 24% (BC; a component of PM2.5) reductions in concentrations during the morning runs compared with trailers without cover. Young children carried in bike trailers are exposed to higher air pollution concentrations compared with the cyclist, particularly during peak morning periods at urban pollution hotspots such as traffic lights.

Size Distributions of Water-Soluble Inorganic Ions in Atmospheric Aerosols During the Meiyu Period in the Yangtze River Delta, China

In order to investigate the chemical composition distributions and pollution characteristics of Total water-soluble inorganic ions (TWSII) in the rain period (Meiyu) in the East Asian summer monsoon season, including the impact of Meiyu on air pollution in the Yangtze River Delta, East China, the gaseous pollutant concentrations, the 9 sizes segregated particles, and water-soluble inorganic ions of aerosols were measured on the north shore of Taihu Lake from June 4 to July 5, 2016. Results show that the mass concentrations of atmospheric particulate matters (PM2.5 and PM10) and main gaseous pollutants (SO2, NO2, CO, and O3) decrease during the Meiyu period, with the largest decline in PM10 and the smallest in CO. TWSII in atmospheric particles are mainly concentrated in fine particles during the Meiyu period. The values of ρ (TWSII) for PM1.1, PM1.1–2.1, and PM2.1–10 before the Meiyu onset are generally greater than those during the Meiyu period. During the first pollution process, the ρ(TWSII) for PM1.1 and PM1.1–2.1 first increase to the peak values, and then decrease during the moderate rainfall period, when the ρ(TWSII) in PM2.1–10 increase to its maximum before the Meiyu onset. The mass concentrations for anions, cations, and total ions at different particle-size sections all exhibit bimodal distributions before and after the Meiyu onset. The mass concentration peaks at a particle size of 1.1–2.1 μm for fine particles, while at 5.8–9.0 μm (before the Meiyu onset) and 9.0–10.0 μm (during the Meiyu period) for coarse particles, respectively. The peak particle size for mass concentration of coarse particles moves toward larger sizes during the Meiyu period. The mass concentrations of SO42− at different particle-size sections show a bimodal distribution before the Meiyu onset and a multi-modal distribution during the Meiyu period. The mass concentrations of NO3− at different particle-size sections show a bimodal distribution before the Meiyu onset and a unimodal distribution during the Meiyu period. The mass concentrations of NH4+ at different particle-size sections present a bimodal distribution before and after the Meiyu onset, with the particle-size for peak concentrations distributing in 1.1–2.1 and 5.8–9.0 μm before the Meiyu onset, and 9.0–10.0 μm during the Meiyu period. The mean value of nitrogen oxidation ratio (NOR) is higher before the Meiyu onset than after, indicating that the secondary conversion of NO2 before the Meiyu onset is enhanced. The sulfur oxidation ratio (SOR) values are greater than NOR values, but the concentrations of NO2 in the same period during the Meiyu period are higher than those of SO2, which indicates that the secondary conversion of SO2 during the Meiyu period on the north bank of Taihu Lake is stronger than that of NO2. During the whole observation, the contribution of stationary sources mainly contributed to the atmospheric particulate matters during the Meiyu period. The contributions of vehicle exhaust and coal combustion to fine particles are more obviously affected by the changes in meteorological conditions during the Meiyu period, and the vehicle emissions contribute more to PM1.1–2.1 than to PM1.1.

Elemental composition of fine and coarse particles across the greater Los Angeles area: Spatial variation and contributing sources

The inorganic components of particulate matter (PM), especially transition metals, have been shown to contribute to PM toxicity. In this study, the spatial distribution of PM elements and their potential sources in the Greater Los Angeles area were studied. The mass concentration and detailed elemental composition of fine (PM2.5) and coarse (PM2.5-10) particles were assessed at 46 locations, including urban traffic, urban community, urban background, and desert locations. Crustal enrichment factors (EFs), roadside enrichments (REs), and bivariate correlation analysis revealed that Ba, Cr, Cu, Mo, Pd, Sb, Zn, and Zr were associated with traffic emissions in both PM2.5 and PM2.5-10, while Fe, Li, Mn, and Ti were affected by traffic emissions mostly in PM2.5. The concentrations of Ba, Cu, Mo, Sb, Zr (brake wear tracers), Pd (tailpipe tracer), and Zn (associated with tire wear) were higher at urban traffic sites than urban background locations by factors of 2.6–4.6. Both PM2.5 and PM2.5-10 elements showed large spatial variations, indicating the presence of diverse emission sources across sampling locations. Principal component analysis extracted four source factors that explained 88% of the variance in the PM2.5 elemental concentrations, and three sources that explained 86% of the variance in the PM2.5-10 elemental concentrations. Based on multiple linear regression analysis, the contribution of traffic emissions (27%) to PM2.5 was found to be higher than mineral dust (23%), marine aerosol (18%), and industrial emissions (8%). On the other hand, mineral dust was the dominant source of PM2.5-10 with 45% contribution, followed by marine aerosol (22%), and traffic emissions (19%). This study provides novel insight into the spatial variation of traffic-related elements in a large metropolitan area.

Daily levels of coarse inhalable particles and sick leaves

BACKGROUND AND AIM: Road traffic is typically the main source of coarse inhalable particles (2.5 µmdiameter10 µm) in urban areas. Consequently, exposure is high e.g. during commuting to work, in northern conditions especially during the spring time. Our aim was to evaluate whether daily outdoor levels of coarse inhalable particles are associated with the daily number of new sick leaves in Helsinki, Finland. METHODS: Data on work absenteeism among the employees of the city of Helsinki (approx. 50 000) was obtained for the years 2001-2017. Concentration of coarse inhalable particles was calculated by subtracting daily fine particle concentration from the concentration of inhalable particles, both measured at an urban background monitoring site. Statistical analyses were conducted using generalized additive quasi-Poisson regression, separately for the whole year and the spring dust period (15.3.-15.5). RESULTS:There were almost 2 million sick leaves in the data. The same day coarse particle concentration was associated with an increased risk of sick leave: relative risk for a 10 µg/m increase in exposure was 1.018 (95% confidence intervals 1.005-1.030). Fine particles had similar effect but with one day lag. During the spring dust period, coarse particles were not associated with the outcome. CONCLUSIONS:Exposure to road dust seems to increase the risk of work absenteeism. However, during the spring dust period particle toxicity may be reduced e.g. because of aging of the material during winter. KEYWORDS: air pollution, coarse particles, work absenteeism, short-term

Characterization of Ambient Particulate Matters in an Industry-Intensive Area in Central Taiwan

Atmospheric particulate matters (PMs) were measured in an industry-intensive region in central Taiwan in order to investigate the characteristics and possible sources of PMs. The samplings were simultaneously conducted using a 10- and 3-stage Micro Orifice Uniform Deposit Impactor (MOUDI) from 2017 to 2018. In this study, the characteristics of PMs in this region were evaluated by measuring the mass concentration of PMs and analyzing water-soluble ions and metallic elements, as well as dioxins. Additionally, principal component analysis (PCA) was used to identify the potential sources of PMs. The results showed that the mean concentration of coarse (&gt;1.8 μm), fine (0.1–1.8 μm), and ultrafine (&lt;0.1 μm) particles were 13.60, 14.38, and 3.44 μg/m3, respectively. In the industry-intensive region, the size distribution of ambient particles showed a bi-modal distribution with a high concentration of coarse particles in the spring and summer, while fine particles were dominant in the autumn and winter. The most abundant water-soluble ions of PMs were NO3−, Cl−, and SO42−, while the majority of metallic elements were Na, Fe, Ca, Al, and Mg in different particle sizes. The results of Pearson’s correlation analysis for metals indicated that the particles in the collected air samples were related to the iron and steelmaking industries, coal burning, vehicle exhausts, and high-tech industries. The dioxin concentration ranged from 0.0006 to 0.0017 pg I-TEQ/Nm3. Principal component analysis (PCA) revealed that the contribution to PMs was associated with sea salt, secondary pollutants, and industrial process.

Spatiotemporal analysis of pedestrian exposure to submicron and coarse particulate matter on crosswalk at urban intersection

At the crosswalk of urban traffic intersections, vehicles frequently stop with their engines idling adjacent to it during the red-light period and accelerate with intensified emissions during the green-light period. As a result, pedestrians are inevitably at a higher risk of exposure to near-source traffic-related air pollution while walking on the crosswalk or waiting on the roadside. Therefore, this study focuses on pedestrian exposure to particulate matter on the crosswalk at urban intersections. Firstly, mobile measurements at varied locations of the crosswalk were carried out to reveal the spatial difference of particles on the whole crosswalk. The results show that the concentrations of submicron and coarse particles are higher on the parking crosswalk than that on the non-parking crosswalk. Secondly, mobile measurements at varied heights of crosswalk were carried out to discover the vertical difference of particles on the crosswalk. Particulate concentration is higher at the height of 1.5 m than that at 0.5 m. Thirdly, fixed-site measurements were conducted on the roadside to make a comparison with the crosswalk. Particulate concentration is found to be nearly 6% higher on the crosswalk than that on the roadside. Finally, pedestrian exposure to particulate matter in varied trips on the crosswalk is investigated and the exposure in trips with a 10s–20s delay after the onset of a walk signal is lower than that in other situations. The results can help fully recognize the particulate pollution at intersections and better understand the particulate exposure of pedestrians on crosswalk at urban intersections.

Measurements of ambient air fine (PM≤2.5) and coarse (PM>2.5) particulates concentrations by using of a dust monitoring system

A Fidas Frog sampler is used to collect ambient air pollutants with various particle sizes at the Taichung Science Park in Taichung, Taiwan. The relationship between particle size and total number of ambient air particles is determined. Fine (PM≤2.5) and coarse (PM>2.5) particulate concentrations are obtained as percentages of the total particulate concentration. The mean concentrations of particles of various sizes (PM1, PM2.5, PM4, PM10, and PMtot) and the total number of particles were all highest on February 24, and declined from then until June 30. The particle concentration was strongly correlated with particle size (PM1, PM2.5, PM4, PM10, PMtotal suspended particles (PMtot.)). The relationship was stronger for smaller particles. The fine particulate concentrations (PM≤2.5) that were obtained using the Fidas Frog sampler were around 67.7% of those obtained in a previous study at the same sampling site. The coarse particulate concentrations (PM>2.5) that were obtained using the Fidas Frog sampler were about 89.4% of those obtained in (a previous study at the same sampling site OR JUST that study) (Fang et al., 2019). Finally, the average coarse particle concentrations that were obtained using the Fidas Frog sampler at this Taichung Science Park site were about 3.1 times the thus obtained fine particles concentrations. The main sources of particulate pollutants at the Taichung Science Park site were abrasion processes, crustal materials and products of vehicle wear.

Transport of Aerosols in Underground Mine Workings in Terms of SARS-CoV-2 Virus Threat.

This paper presents a method of implementation and the results of aerosol dispersion tests in underground mine workings. Numerous tests were carried out to determine the potential risk of SARS-CoV-2 coronavirus infection in the underground environment of the mines. The influence of selected parameters of mine air on the possibility and method of aerosol transmission through ventilation routes was experimentally determined in real conditions. The concentration of additional aerosols in the class of ultrafine and fine aerosols increased with the distance from the generator, while the concentration of coarse particles decreased. Assuming the consumption of the solution with which aerosols were generated, even at a small level of 1 cm3/min., the number of additional aerosols was several hundred particles in one cubic centimeter of air at a distance of 50–70 m from the generator. The concentration of ultrafine particles in the range of 40–20,000 nm increased from 122 particles/cm3 to 209 particles/cm3 at air temperature of 12 °C and relative humidity of 95–96%, and from 90 particles/cm3 to 243 particles/cm3 at air temperature of 17 °C and relative humidity of 76–82%, with the increasing distance from the generator (10 m to 50 m).

The impact of biomass burning emissions on protected natural areas in central and southern Mexico.

Biomass burning from grassland, forests, and agricultural waste results in large amounts of gases and particles emitted to the atmosphere, which affect air quality, population health, crop development, and natural vegetation. Regional atmospheric circulations can transport those plumes of pollutants over hundreds of kilometers, affecting vulnerable environments such as those considered protected natural areas (PNAs). This study evaluates the spatiotemporal distribution of active fires detected, and associated emissions, in central and southern Mexico from satellite data between March and June 2017, to assess the impact of the smoke plumes on protected ecosystems. The arrival of smoke plumes to selected PNAs (both near large urban centers and in remote areas) is assessed using airmass forward trajectories from selected emission sources. The spatial distribution of the remotely derived aerosol optical depth confirms the regional impact of particle emissions from the observed fires on PNAs, particularly in central Mexico. The identified areas of high fire density are also associated with large coarse particle concentrations at the surface. Moreover, there is a significant contribution of organic carbon to the total coarse particle mass, 60% on average. Finally, while most of the impact in ambient pollution is observed in PNAs located close to the regions with active fires in southern Mexico and Central America, the long-range transport of smoke plumes reaching the USA was also confirmed.