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Although traffic exhaust emissions in Europe have been drastically reduced, airborne particle emissions caused by brakes and tires are still increasing with the number of vehicles. The measurement of non-exhaust emissions is an emerging technological challenge. We present a custom measurement setup to investigate the brake- and tire-wear emissions of an in-use battery electric vehicle. A separate brake housing and HEPA ventilation enabled airborne brake wear emissions to be measured under realistic conditions without external influences. The emission tests on a chassis dynamometer included particle number concentrations and particle size distribution for diameters of 4 nm to 10 μm. Emission indices were determined for three driving cycles: WLTC Class 3b, WLTC Brake Part 10, and a real driving cycle. Further investigations focused on emission control through regenerative braking and brake coating. Driving with regenerative braking reduced emissions by up to 89.9%, which related to the concentration of particles in the ultrafine/fine size range. Hard-metal brake coating led to a further significant reduction in emissions of up to 78.9%. The results point the way to future RDE measurement of non-exhaust emissions and show the potential of regenerative braking and brake coating to reduce airborne brake wear emissions. [ABSTRACT FROM AUTHOR]

Background and objective: Bronchoscopy is an airborne particle‐generating procedure. However, few methods for safe bronchoscopy have been developed. To reduce airborne particles during bronchoscopy, we created an 'e‐mask', which is a simple, disposable mask for patients. Our objective was to evaluate the e‐mask's protective ability against airborne particles and to assess respiratory adverse events and complications. Methods: Patients with stage 2–4 chronic obstructive pulmonary disease were excluded. We performed visualization and quantifying experiments on airborne particles with and without the e‐mask. We prospectively evaluated whether wearing the e‐mask during bronchoscopy was associated with the incidence of patients requiring >5 L/min oxygen to maintain >90% oxygen saturation, and patients with >45 mm Hg end‐tidal carbon dioxide (EtCO2) elevation, in addition to complications, compared to historical controls. Results: In the visualization experiment, more than ten thousand times of airborne particles were generated without the e‐mask than with the e‐mask. The volume of airborne particles was significantly reduced with the e‐mask, compared to that without the e‐mask (p = 0.011). Multivariate logistic regression analysis revealed that wearing the e‐mask had no significant effect on the incidence of patients requiring >5 L/min oxygen to maintain >90% oxygen saturation, (p = 0.959); however, wearing the e‐mask was a significant factor in >45 mm Hg EtCO2 elevation (p = 0.026). No significant differences in complications were observed between the e‐mask and control groups (5.8% vs. 2.5%, p = 0.395). Conclusion: Wearing the e‐mask during bronchoscopy significantly reduced the generation of airborne particles during bronchoscopy without increasing complications. [ABSTRACT FROM AUTHOR]

Advanced air treatment systems have the potential to reduce airborne infection risk, improve indoor air quality (IAQ) and reduce energy consumption, but few studies reported practical implementation and performance. PlasmaShield ® , an advanced multi-modal HVAC-integrated system, was directly compared with a standard MERV-13 system in a post-surgical paediatric healthcare setting. The evaluation entailed monitoring of multi-size airborne particles, bioaerosols and key IAQ parameters. Measurements were taken for outside air, supply air and air in the occupied space for 3 days prior to, and after, the installation of the PlasmaShield system. Compared with the existing arrangement, very significant reductions in particle number concentrations were observed in the occupied space, especially with virus-like submicron particles. Significant reductions in airborne culturable bacteria and fungi were observed in the supply air, with more modest reductions in the occupied space. In the case of virus-like particles, there was an eight-fold improvement in equivalent clean air, suggesting a five-fold infection risk reduction for long-range exposure. The data suggest multiple benefits of airborne particle and bioaerosol reduction, with applications beyond healthcare. Long-term studies are recommended to confirm the combined IAQ, health and energy benefits.

Evidence suggests that myocardial interstitial fibrosis, resulting from cardiac remodeling, may possibly be influenced by mechanisms activated through the inhalation of airborne pollutants. However, limited studies have explored the relationship between lifetime exposure to carbon-based particles and cardiac fibrosis, specially using post-mortem samples. This study examined whether long-term exposure to air pollution (estimated by black carbon accumulated in the lungs) is associated with myocardial fibrosis in urban dwellers of megacity of Sao Paulo. Data collection included epidemiological and autopsy-based approaches. Information was obtained by interviewing the next of kin and through the pathologist's report. The individual index of exposure to carbon-based particles, which we designed as the fraction of black carbon (FBC), was estimated through quantification of particles on the macroscopic lung surface. Myocardium samples were collected for histopathological analysis to evaluate the fraction of cardiac fibrosis. The association between cardiac fibrosis and FBC, age, sex, smoking status and hypertension was assessed by means of multiple linear regression models. Our study demonstrated that the association of FBC with cardiac fibrosis is influenced by smoking status and hypertension. Among hypertensive individuals, the cardiac fibrosis fraction tended to increase with the increase of the FBC in both groups of smokers and non-smokers. In non-hypertensive individuals, the association between cardiac fibrosis fraction and FBC was observed primarily in smokers. Long-term exposure to tobacco smoke and environmental particles may contribute to the cardiac remodeling response in individuals with pre-existing hypertension. This highlights the importance of considering hypertension as an additional risk factor for the health effects of air pollution on the cardiovascular system. Moreover, the study endorses the role of autopsy to investigate the effects of urban environment and personal habits in determining human disease. [Display omitted] • Study exploring epidemiological and autopsy-based approaches of Sao Paulo dwellers. • Association of black carbon and cardiac fibrosis depends on smoking and hypertension. • Hypertensive are more sensitive to effects of air pollution on cardiac remodeling. • Effects on cardiorespiratory health standpoint support pollutants control policies. [ABSTRACT FROM AUTHOR]

Although traffic exhaust emissions in Europe have been drastically reduced, airborne particle emissions caused by brakes and tires are still increasing with the number of vehicles. The measurement of non-exhaust emissions is an emerging technological challenge. We present a custom measurement setup to investigate the brake- and tire-wear emissions of an in-use battery electric vehicle. A separate brake housing and HEPA ventilation enabled airborne brake wear emissions to be measured under realistic conditions without external influences. The emission tests on a chassis dynamometer included particle number concentrations and particle size distribution for diameters of 4 nm to 10 μm. Emission indices were determined for three driving cycles: WLTC Class 3b, WLTC Brake Part 10, and a real driving cycle. Further investigations focused on emission control through regenerative braking and brake coating. Driving with regenerative braking reduced emissions by up to 89.9%, which related to the concentration of particles in the ultrafine/fine size range. Hard-metal brake coating led to a further significant reduction in emissions of up to 78.9%. The results point the way to future RDE measurement of non-exhaust emissions and show the potential of regenerative braking and brake coating to reduce airborne brake wear emissions.

Abstract Recently, as the concentration of fine dust in the atmosphere has increased due to an increase in the use of fossil fuel power plants, automobiles, and factories, it has been increasingly important to measure fine dust in the atmosphere. This is because exposure to fine dust is closely related to the incidence of respiratory and cardiovascular diseases and eventually affects mortality. In this paper, we introduce a MEMS particle sensor based on the resonance frequency shift according to added particle mass. The actuation is driven by Aluminum nitride (AlN), and the total thickness is 2.8 μm. A laser doppler vibrometer (LDV), an optical measuring instrument, was used to measure the resonance frequency of the sensor. Airborne particles naturally were deposited on the sensor. To show the frequency shift according to the particle mass, the frequency shift was measured by dividing the case where the deposited particle mass was small and large. In each case, the frequency shift according to the deposited particle mass was predicted and compared with the frequency shift measured by LDV. It was shown that the deposited particle mass and frequency shift are proportional. The deposition of particulate mass was estimated by image analysis. The frequency shift caused by the particle mass deposited on the sensor was defined as the sensitivity of the sensor. The estimated sensitivity of the sensor is 0.219 to 0.354 kHz/pg.

Introduction: The indoor environment of dental clinics may endanger dental patients and personnel and due to a great variety of air pollutants throughout the usual dental operation. The purpose of the present cross-sectional study was the evaluation of Indoor Air Quality (IAQ) and factors affecting it in a dentistry faculty of Arak University of Medical Sciences. Material and methods: The IAQ of five dental active wards and the patient waiting room was evaluated. The concentrations of Total Volatile Organic Compounds (TVOC), CO2, particulate matter, and bioaerosols were measured. Results: The TVOCs concentration in sampling locations ranged between 817 to 3670 μg/m3 during dental work and exceeded the Leadership in Energy and Environmental Design (LEED) guideline in all sampling locations. The highest values of Particulate Matter (PM) for PM10, PM2.5, and PM1 were observed in the periodontics ward, while the lowest values were observed in the endodontics ward. The PM2.5 concentrations exceeded the WHO limit in periodontics and pediatric wards. TVOC levels had a significant positive correlation with temperature (r=0.374, p

Commercial spray products are commonly used in daily life and airborne particles generated by these products may cause adverse health effects. Our study was aimed to characterize the behaviors of airborne particles from spray products and to determine the deposition loss rate. Four categories of spray products with highly frequent use - air fresheners, fabric deodorants, window cleaners, and a bathroom cleaner - were selected for the study. The products were applied in a cleanroom according to the instructions for use. Airborne particles (10–10,000 nm) were measured within the breathing zone of a user with a scanning mobility particle sizer and an optical particle spectrometer. Additionally, filter sampling was performed to examine the morphological characteristics of the particles using a field emission-scanning electron microscope (FE-SEM). The initial concentration and particle size distribution varied among different spray types and products. Two propellant-type air fresheners that we tested showed a high initial concentration of smaller sized particles. However, one of these and all hand-pressure type propellants showed a low initial concentration in all size ranges. We observed that particles in nucleation mode (10–31.6 nm) decreased and aggregated particles shifted to accumulation mode (100–1,000 nm) over time. The FS-SEM analysis confirmed the aggregation of nano-sized particles for all products. The deposition loss rates of various particle sizes depended on the initial concentration and distribution of particle sizes. For two air fresheners with high initial concentrations, the loss rate of small-sized particles was higher than that of the other products whereas the particle loss rate of large-sized particles was higher, regardless of initial concentration. The results of this study can give us useful information in the behaviors of airborne particles in the consumer spray products and resulting exposure assessment especially in the application to the exposure modeling of spray products.

The influenza virus and SARS-CoV-2 cause trivial upper and severe lower respiratory infections (Influenza virus 290,000 to 650,000 deaths/year). These viruses come into contact with the airways either by direct projection, by secondary inhalation of airborne droplets, or by handling (fomites). The objective of this article is to clarify the mechanisms of production and penetration of droplets of secretions emitted during all expiratory phenomena likely to transport these viruses and come into contact with the respiratory mucosa. The droplets > 5 μm follow the laws of ballistics, those < 5 μm follow Brownian motion and remain suspended in the air. The aerosols of droplets are very heterogeneous whether the subject is healthy or sick. During an infectious period, not all droplets contain viral RNA. If these RNAs are detectable around patients, on surfaces, and in the ambient air at variable distances according to the studies (from 0.5 m to beyond the patient's room), this is without prejudice to the infectious nature (viability) of the virus and the minimum infectious dose. There is a time lag between the patient's infectious period and that of RNA detection for both viruses. Subsequently, the inhaled particles must meet the laws of fluid dynamics (filtration) to settle in the respiratory tree. All of this partly explains the contagiousness and the clinical expression of these two viruses from the olfactory cleft to the alveoli. [ABSTRACT FROM AUTHOR]

Abstract Background Surgical-site infections due to intraoperative contamination are chiefly ascribable to airborne particles carrying microorganisms. The purpose of this study is to identify the actions that increase the number of airborne particles in the operating room. Methods Two surgeons and two surgical nurses performed three patterns of physical movements to mimic intraoperative actions, such as preparing the instrument table, gowning and donning/doffing gloves, and preparing for total knee arthroplasty. The generation and behavior of airborne particles were filmed using a fine particle visualization system, and the number of airborne particles in 2.83 m3 of air was counted using a laser particle counter. Each action was repeated five times, and the particle measurements were evaluated through one-way analysis of variance multiple comparison tests followed by Tukey–Kramer and Bonferroni–Dunn multiple comparison tests for post hoc analysis. Statistical significance was defined as a P value ≤ .01. Results A large number of airborne particles were observed while unfolding the surgical gown, removing gloves, and putting the arms through the sleeves of the gown. Although numerous airborne particles were observed while applying the stockinet and putting on large drapes for preparation of total knee arthroplasty, fewer particles (0.3–2.0 μm in size) were detected at the level of the operating table under laminar airflow compared to actions performed in a non-ventilated preoperative room (P

Highlights • A two-part train traffic emission factors model is built. • The model could predict the PM10 level at a railway station platform in a tunnel. • The two terms in this model are brake effect term and accumulative effect term. • The relationship between PM10 and train frequency in both terms is linear. • The two terms equally affect the PM10 level at train station platforms. Abstract In 2017 a new railway tunnel containing two stations opened in Stockholm, Sweden. A series of field measurements were carried out on the platforms in this tunnel before and after it was opened for normal traffic. These measurements were used to investigate the contribution of airborne particle emissions from wear processes to total train emissions. This field data was used to develop a two-part train traffic emission factor model for PM10. The two parts are the accumulative effect term (relating to operating distance such as wheel-rail contact and overhead electric line sliding contact) and a brake effect term (relating to the number of braking operations such as brake disc and brake pad contact). The results show that operating a single trial train at a higher than normal frequency on an otherwise empty platform increases the platform particulate concentration until the concentration reaches a steady value. The model suggests that brake emissions account for about 50% of the total emissions measured in the tunnels. [ABSTRACT FROM AUTHOR]

Abstract Indoor air environment inside operating room (OR) is crucial for the success of surgical operation. The opening and closing process of sliding door is very common in OR. In this case, the designed positive pressure will disappear. Since the air exchange characteristic at the interface of the sliding door will influence the Surgical Site Infection risk, the combined effects of temperature and pressure differences on interface airflow along with the air infiltration volume and intruding particles caused by the airflow are studied by theoretical and numerical methods. Two different cases are compared, where the temperature of OR is lower or higher than that of anteroom, respectively. Results show that the contaminants accumulate in the upper space of the OR due to the airflow pattern between two rooms when the temperature of OR is lower than the anteroom. This will increase the possibility that airflow carrying contaminants intrudes into OR. On the contrary, the contaminants are controlled in the lower space of the OR when the temperature of OR is higher than that of anteroom. On average, the particle intrusion ratio of the second case decreases by 55% compared with that of the first case. So, it is helpful to protect the clean environment of OR when the temperature of OR is higher than that of the anteroom. Moreover, the air infiltration volume of the closing phase is found unequal to that of the opening phase. This study provides the useful information for maintaining a clean indoor environment under operational condition. Highlights • Interface airflow of sliding door with temperature/pressure differences is studied. • Theoretical model was established for interface flow under the coupled effect. • Air infiltration rate of the closing phase is more than that of the opening phase. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to evaluate a potential risk of intraoperative contamination associated with clothing systems and surgeon's motion in total joint replacement. Methods: The airborne particle concentrations at different locations around a single operating surgeon wearing standard surgical gown (SG) or modern 'space suit' (SS) were compared. The particles in the size of ≥0.5 μm (roughly corresponding to a mean diameter of squamous epithelial cells) were counted at the following three locations: (1) ≈10 cm inferior to the wrist; (2) ≈10 cm posterior to the feet; and (3) near the chest (operative field) under condition either with or without the surgeon's motion (stepping in place at ~1 Hz). Results: The difference in the surgical clothing systems did not significantly affect the mean particle counts detected near the wrist and chest ( p = 0.307 and 0.155, respectively). However, the particle count near the feet was 154 times higher in SS than SG (4630 ± 2795 vs. 30 ± 23 N/F, p = 0.023). The simple stepping of the surgeon with SS increased contaminants near the chest 31 times as compared to the condition without motion (1053 ± 709 vs. 34 ± 31 N/F, p = 0.0032). Although the particle count was less affected by the motion in SG than SS, contaminants near the chest increased ten times after the stepping in the use of SG ( p = 0.032). Conclusion: The present results suggest that the intraoperative motion of a surgeon may considerably increase airborne particle/bacterial concentration in the operative field. This can be a much higher likelihood in SS rather than SG because of air blow-off from the incorporated cooling fan. [ABSTRACT FROM AUTHOR]

Environment and disease problems have negative effects on the development of egg industry. Airborne particles, airborne microorganisms and ammonia are the main contaminants emitted from laying hen houses. These air contaminants emitted from animal buildings may harm the environment and public health. PM2.5 can deposit in human lung, causing respiratory responses. It increases the risk of Asthma, vascular inflammation, lung cancer and heart disease. Airborne microorganisms with airborne particles as the carrier can cause cross disease infection of birds, threatening the biosecurity of the farm. Ammonia may harm the health of workers and birds, and reduce the animal production performance. In this research, the emission of airborne particles, airborne microorganisms and ammonia from a breeding hen house were monitored in the winter daytime in Beijing, China. Approximate 14,000 layer breeding hens (32 week-old at the start of the experiment) and 400 adult male chickens were confined in 3 stair-step cages in the tunnel-ventilated house. During the experiment, fresh air was pulled in through 38 air inlets, evenly distributed along the sidewalls, and only one of the six exhaust fans (the experimental fan) was operated intermittently on a thermostat to control indoor air temperature. A new sampling system for airborne particles, airborne microorganisms and ammonia was designed, respectively. The airborne particles sampling system consists of a PVC sampling manifold, a glass fiber membrane, a drying tube, a flow meter and a vacuum pump. The ammonia sampling system consists of a PVC sampling manifold, an air washing bottle with boric acid solution, a drying tube, a flow meter and a vacuum pump. The airborne microorganisms sampling system consists of a PVC sampling manifold, an airborne microorganism sampler and a vacuum pump. The study was carried out in the winter daytime using these sampling systems. Average airborne particle and ammonia concentrations at the outlet sampling location were measured from 8:00—18:00 on each sampling day. Airborne microorganism concentration was sampled at the outlet location on each sampling day. Starting time were 8:00 and 13:00 (twice, 30 min for each time). In the experiment period, the temperature and humidity inside and outside the laying hen house were tested and recorded. Ventilation rate was calculated by the static pressure difference and the fan performance curve supplied by the manufacturer. The results showed that:1) In the winter, the breeding hen house in Beijing conducted intermittent ventilation. The ventilation rate per hen and the ambient temperature showed positive correlation (P<0.05, R2=0.8837). 2) The air temperature in the laying hen house in the winter was controlled between 18.0 and 20.0 ºC. In the experiment period, the emission concentration of airborne particles was between 0.5 and 0.8 mg/m3, averaging 0.7±0.1 mg/m3. The emission rate was between 1.0 and 1.5 mg/h per hen, averaging 1.2±0.2 mg/h. The emission concentration of airborne microorganism was between 4.0 and 4.5 log10 CFU/m3, averaging 4.2±0.1 log10 CFU/m3. The emission rate was between 4.3 and 4.8 log10 CFU/h per hen, averaging 4.5±0.1 log10 CFU/h. The emission concentration of ammonia was between 7.6 and 14.3 mg/m3, averaging 10.8±2.3 mg/m3. The emission rate was between 8.1 and 13.7 mg/h per hen, averaging 11.1±1.9 mg/h. Ammonia emission rate of this house was higher than that of layer hen houses with manure belt, but lower than that of high rise layer hen houses. In the experiment period, the ambient temperature was lower than indoor temperature. The ambient temperature and the ventilation rate showed small fluctuation. No correlativity was found between air contaminants emission concentration, emission rate and ambient temperature, ventilation rate, and indoor relative humidity. The results provided basic data and theoretical basis for the air contaminants emission from layer hen houses in China. [ABSTRACT FROM AUTHOR]

Airborne particulate matter consisting of ionic species, salts, heavy metals and carbonaceous material is one of the most serious environmental pollutants owing to its impacts on the environment and human health. Although elemental and organic carbon compounds are known to be major components of aerosols, information on the elemental composition of particulate matter remains limited because of the broad range of compounds involved and the limits of analytical instruments. In this study, we investigated water-soluble and -insoluble organic compounds in fine (PM 2.5 ) airborne particles collected during winter in Korea to better understand the elemental compositions and distributions of these compounds. To collect ultra-high-resolution mass profiles, we analyzed water-soluble and -insoluble organic compounds, extracted with water and dichloromethane, respectively, using an ultra-high-resolution 15 T Fourier transform ion cyclotron resonance (15T FT-ICR) mass spectrometer in positive ion mode (via both electrospray ionization [ESI] and atmospheric pressure photoionization [APPI] for water-extracts and via APPI for dichloromethane-extracts). In conjunction with the FT-ICR mass spectrometry (MS) data, subsequent two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) data were used to identify potentially hazardous organic components, such as polycyclic aromatic hydrocarbons. This analysis provided information on the sources of ambient particles collected during winter season and partial evidence of contributions to the acidity of organic content in PM 2.5 particles. The compositional and structural features of water-soluble and -insoluble organic compounds from PM 2.5 particles are important for understanding the potential impacts of aerosol-carried organic substances on human health and global ecosystems in future toxicological studies. [ABSTRACT FROM AUTHOR]

Viable bacteria on water-insoluble airborne particles were detected in the urban atmosphere of Kumamoto (134°45′E, 32°28′N), Japan, in autumn 2008. Airborne particles were collected onto film-covered Cu meshes under clear weather conditions. The samples were stained by fluorescent stains, and then viewed and photographed with an epifluorescent microscope. Non-biological and bacterial parts in particles larger than 0.8 μm were distinguished by their morphologies, fluorescent colors and fluorescent intensities. Bacterial viable statuses were discriminated according to cell membrane damage. In total, 2681 particles were investigated and it was found that 78 airborne particles were associated with bacteria. Viable bacteria were identified on 48 particles. A few particles carried multiple viable bacteria. These results provide the evidence that airborne particles act as carriers of viable bacteria in the atmosphere.

A novel method for detecting and sizing airborne particles at single particle level is presented in this paper. When a particle hits a metal electrode which is grounded, electrostatic charges will be transferred between the particle and the electrode. As a result, an electrical current pulse will be generated in the measurement system. The number of the signal pulse represents the number of particles in the sample. To determine the effect of the particle size on the magnitude of the signal, the correlation between the magnitude of the signal and the size of particle was experimentally investigated. The results show that the magnitude of the measured signal is linearly proportional to the square of particle’s diameter. Such a correlation can be used to evaluate particle size from the measured signal. The airborne particle detection method presented in this paper can be used for counting and sizing airborne particles at single particle level. [ABSTRACT FROM AUTHOR]

Airborne particulate matter (PM) pollution has caused many deleterious effects on atmospheric environment and people’s health. Fiber filtration has been regarded as one of the efficient and economical ways for removing particles from gas streams. To reveal the dynamic capture processes of airborne particles by fibrous filters, and their effects on filtration performance, a lattice Boltzmann modeling approach coupled with discrete element method (LB-DEM), is used for simulations of airborne particle deposition on an individual fiber. The mutual influences between the dynamic particle transport/deposition and the fluid flow are considered. The model well predicts the formation of the dendrites and the dynamic progression of the deposit under different capture mechanisms. The adhesion parameter is proved to have a dominant effect on the dynamic deposition processes and filtration performance. Increases in adhesion parameter lead to looser particle dendrites, faster deposition rates and better filtration efficiencies. The smaller particles tend to have larger pressure drops and more compact dendrite structures at the same deposition mass. [ABSTRACT FROM AUTHOR]