Ultrafine Particle Concentrations Research Articles

Indoor Environmental Quality in Portuguese Office Buildings: Influencing Factors and Impact of an Intervention Study

Office workers spend a considerable part of their day at the workplace, making it vital to ensure proper indoor environmental quality (IEQ) conditions in office buildings. This work aimed to identify significant factors influencing IEQ and assess the effectiveness of an environmental intervention program, which included the introduction of indoor plants, carbon dioxide (CO2) sensors, ventilation, and printer relocation (source control), in six modern office buildings in improving IEQ. Thirty office spaces in Porto, Portugal, were randomly divided into intervention and control groups. Indoor air quality, thermal comfort, illuminance, and noise were monitored before and after a 14-day intervention implementation. Occupancy, natural ventilation, floor type, and cleaning time significantly influenced IEQ levels. Biophilic interventions appeared to decrease volatile organic compound concentrations by 30%. Installing CO2 sensors and optimizing ventilation strategies in an office that mainly relies on natural ventilation effectively improved air renewal and resulted in a 28% decrease in CO2 levels. The implementation of a source control intervention led to a decrease in ultrafine particle and ozone concentrations by 14% and 85%, respectively. However, an unexpected increase in airborne particle levels was detected. Overall, for a sample of offices that presented acceptable IEQ levels, the intervention program had only minor or inconsistent impacts. Offices with declared IEQ problems are prime candidates for further research to fully understand the potential of environmental interventions.

Interaction of Cooking-Generated Aerosols on the Human Nervous System and the Impact of Caloric Restriction Post-Exposure

Background: The inhalation of cooking-generated aerosols could lead to translocation to the brain and impact its function; therefore, the effects of cooking-generated aerosols on healthy adults were investigated using an electroencephalograph (EEG) during the 2 h period post-exposure. Methods: To explore any changes from the impact of exposure to cooking-generated aerosols on the human brain due to the absence of food intake during exposure, we divided the study participants into three groups: (A) no food intake for 2 h (2 h-zero calorie intake), (B) non-zero calorie intake, and (C) control group (simulated cooking). Results: The ultrafine particle concentrations increased from 9.0 × 103 particles/cm3 at the background level to approximately 8.74 × 104 particles/cm3 during cooking. EEGs were recorded before cooking (step 1), 60 min after cooking (step 2), 90 min after cooking (step 3), and 120 min after cooking (step 4). Comparing the non-zero calorie group with the control group, it was concluded that exposure to cooking-generated aerosols resulted in a 12.82% increase in the alpha band two hours post-exposure, compared to pre-exposure. The results revealed that zero calorie intake after exposure mitigated the impacts of cooking-generated aerosols for the alpha, beta3, theta, and delta bands, while it exacerbated effects on the whole brain for the beta1 and beta2 bands. Conclusions: While these are short-term studies, long-term exposure to cooking-generated ultrafine particles can be established through successive short-term exposures. These results underscore the need for further research into the health impacts of cooking-generated aerosols and the importance of implementing strategies to mitigate exposure.

Ten questions concerning particle exposure in open electrosurgery and its control strategies

The increasing use of high-frequency electrosurgical pencils in open surgeries has heightened concerns about the adverse implications of electrosurgical smoke (ES) on perioperative personnel. Since 2015, there has been an increasing amount of research on electrosurgical smoke particles annually. Despite data discrepancies, nanoparticles (core particle size <200 nm) generally dominate in number distributions. Particulate matter (PM) concentration is closely related to the type of target tissue. Most studies show that ultrafine particle (UFP) concentrations near the main surgeon’s breathing zone inversely correlate with operating room air changes and positively correlate with the power of the electrosurgical pencil. Local smoke evacuation devices with negative ions, specialized filters and N95 respirators are more effective in protecting perioperative staff health, particularly against UFPs. The objective is to summarize particle exposure knowledge in open electrosurgery and establish a research agenda to protect medical personnel from ES exposure.

Seasonal variation of particle number concentration in a busy urban street with exposure assessment and deposition in human respiratory tract

Ultrafine particles (UFP) associated with air quality and health impacts are a major concern in growing urban regions. Concentrations of UFP (particles of size between 10 and 100 nm) and accumulation mode (Nacc) (particles of size >100 and up to 1000 nm), are analyzed over a highly polluted megacity, Delhi, in conjunction with vehicular flow density, during peak (morning, and evening) and non-peak hours. UFP contributes ≥60% to total particle concentration during autumn and monsoon. UFP concentrations are about 50,000 particles per cm3 in winter which reduces to about 25,000 particles during monsoon. Nacc are about 20,000 (winter) and 10,000 (monsoon) particles per cm3. UFP concentration and Nacc during peak hours are at least twice higher than those obtained in non-peak hours, confirming the dominant influence of emissions from vehicular exhaust in the study region. Seasonal analysis of UFP size distribution reveals that direct emissions dominate the particle concentrations during winter and autumn, whereas new particle formation mechanism contributes the highest in spring and summer. Assessment of inhalable particle number concentration and particle deposition in the human respiratory tract using Multiple Path Particle Dosimetry (MPPD) model, performed for the first time, shows that the order in which these particles deposit in the human respiratory tract is alveoli > bronchiole > bronchus. The deposition ranges between 10 and 18 million nanoparticles during different hours of the day, whereas the estimated inhalable particle concentration (IPN) varies between 0.5 and 1 billion. Results on the IPN during activities classified from light (walking), medium, heavy, very heavy to severe (long-distance running) provide insights into health effects on vulnerable populations. These quantitative results obtained over a megacity on hourly and seasonal variations of nanoparticles along with IPN and deposition rates for different activities are important, and are invaluable inputs for developing mitigation policies aimed to improve air quality and public health, both of which are major concerns in South Asia.

Airborne ultrafine particle concentrations and brain cancer incidence in Canada’s two largest cities

BackgroundMalignant brain tumours are rare, but are important to study because survival rates are low and few modifiable risk factors have been identified. Existing evidence suggests that outdoor ultrafine particles (UFPs) (particulate matter < 100 nm, sometimes referred to as nanoparticles) can deposit in the brain and could encourage initiation and progression of cancerous tumours, but epidemiological data are limited. MethodsHigh-resolution estimates of outdoor UFP concentrations and size were linked to residential locations of approximately 1.5 million people in Montreal and Toronto, Canada from 2001 to 2015. Cox proportional hazards models were used to estimate associations between annual average outdoor UFPs and malignant brain tumour incidence while adjusting for potential confounding factors including other outdoor air pollutants. FindingsIn total, 1400 incident brain tumour cases occurred during follow-up. Consistent positive associations were observed between long-term exposures to outdoor UFPs and brain tumour incidence with increased risk ranging from 10.5% (95% CI: −1.4, 24.0%) to 15.3% (95% CI: 0.4, 32.5%) per 10,000 particle/cm3 increase. Long-term exposures to oxidant gases, black carbon, or fine particulate matter (PM2.5) were not associated with increased brain tumour incidence. InterpretationOur results suggest that long-term exposures to outdoor UFPs are associated with an increased risk of developing malignant brain tumours. On an absolute scale, the magnitude of this risk translates into approximately 24 additional cases per year per 10,000 particle/cm3 increase in annual average outdoor UFPs in a hypothetical city of 3-million people. FundingCanadian Institutes of Health Research (CIHR) Foundation Grant and The United States Health Effects Institute (HEI).

Comparison of aerosol number size distribution and new particle formation in summer at alpine and urban regions in the Guanzhong Plain, Northwest China

Ultrafine particles play a crucial role in understanding climate change, mitigating adverse health effects, and developing strategies for air pollution control. However, the factors influencing the occurrence and development of new particle formation (NPF) events, as well as the underlying chemical mechanisms, remain inadequately explained. This study compared number concentrations and size distributions of atmospheric ultrafine particles at Xi'an (urban area) and the summit of Mt. Hua (alpine region) in summer to investigate the NPF mechanism and particle growth in both clean and polluted areas of the Guanzhong Plain. The average particle number concentration in Xi'an was significantly higher than that at Mt. Hua. The diurnal variation of total particle number concentration differed between Xi'an and Mt. Hua indicating a divergence in influencing factors. The size distributions in Xi'an varied across different timescales and weather conditions, whereas Mt. Hua exhibited little variation. This stability at Mt. Hua is attributed to its cleaner background atmosphere and the steady influx of aging particles with larger diameters transported from the free atmosphere. In both areas, geometric mean diameters (GMDs) were inversely proportional to particle number concentrations suggesting that increase in particle numbers were primarily due to the generation of smaller particles. The potential governing factors for NPF events differed somewhat between the urban and mountainous stations. In the urban area, intense local stationary and mobile emission sources promoted the growth of newly formed nanoparticles, with ozone-oxidized condensable vapors serving as key precursors. In contrast, at the mountainous station, NPF process were significantly influenced by anthropogenic precursors from long-range transport and locally emitted biogenic organics. The rapid increase in ultrafine particle concentrations primarily poses serious health risks and degrades air quality in urban areas, while also contributing to climate-related effects in alpine regions.

Measurement report: Contribution of atmospheric new particle formation to ultrafine particle concentration, cloud condensation nuclei, and radiative forcing – results from 5-year observations in central Europe

Abstract. As an important source of sub-micrometer particles, atmospheric new particle formation (NPF) has been observed in various environments. However, most studies provide little more than snapshots of the NPF process due to their underlying observations being limited in space and time. To obtain statistically relevant evidence on NPF across various environments, we investigated the characteristics of NPF based on a 5-year dataset of the German Ultrafine Aerosol Network (GUAN). The results were also compared with observations in previous studies, with the aim to depict a relatively complete picture of NPF in central Europe. The highest NPF occurrence frequency was observed in regional background sites, with an average of about 19 %, followed by urban background (15 %), low-mountain-range (7 %), and high Alpine (3 %) sites. The annual mean growth rate between 10 and 25 nm varied from 3.7–4.7 nm h−1, while the formation rate with same size range 10–25 nm from 0.4 to 2.9 cm−3 s−1. The contribution of NPF to ultrafine particles (UFPs) was about 13 %, 21 %, and 7 % for the urban background, regional background, and low mountain range, respectively. The influence of NPF on cloud condensation nuclei (CCN) number concentration and the aerosol extinction coefficient for NPF days was the highest in mountainous areas. These findings underscore the importance of local environments when assessing the potential impact of NPF on regional climate in models, and they also emphasize the usefulness of a long-term aerosol measurement network for understanding the variation in NPF features and their influencing factors over a regional scale.

A comprehensive study on the validation and application of multi-lognormal distribution models for atmospheric particles

The particle number size distribution (PNSD) is crucial for evaluating air quality and mitigating environmental pollution, as particles of different sizes have diverse effects on human health and climate. However, obtaining a comprehensive understanding of PNSD is challenging due to its inherent complexities and variability. Multi-lognormal distribution models are employed to fit PNSD, as seen in climate models, but discrepancies between model fits and observed PNSD persist. This study adopts hourly data from 2017 to 2020 across eight monitoring sites in diverse environments—rural, urban, mountainous, and polar, and compares the observed PNDS with those simulated by multi-lognormal distribution models. The results demonstrated that the model generally achieved a high correlation with observed PNSD data (r2 > 0.75), effectively capturing key characteristics of nucleation and Aitken mode particles. However, the model had a tendency to overestimate the total number concentration by approximately 1.09 times, particularly noticeable under conditions of high concentrations of smaller particles. The model successfully represented prevalent bimodal size distribution patterns in urban areas with high ultrafine particle concentrations, though its performance was slightly less accurate in scenarios involving trimodal distributions. Despite these strong correlations and the model's ability to reflect diurnal and seasonal variations, which suggests its broad applicability and utility, there were notable limitations on smaller time scales and in specific particle size ranges. These limitations were particularly evident in capturing detailed phenomena relevant to new particle formation events, indicating areas where model refinement is necessary. The results highlighted the importance of investigating discrepancies between model predictions and actual observations, which is crucial for refining climate models that utilize PNDS. The uniform comparison facilitated a detailed exploration of particle properties from model results, offering deeper insights into aerosol behavior and its environmental impacts.

Investigation into personal exposure to ultrafine particle (UFP) in Phnom Penh, Cambodia: A pilot study

This pilot study aimed to examine personal exposure to ultrafine particles (UFP or particle smaller than 100 nm) in Phnom Penh, Cambodia through the assessment of different transportation modes, travel routes, and the comparison of indoor and outdoor activities. A handheld UFP counter was used to record the UFP size, concentration and as well as Lung Deposited Surface Area (LDSA). GPS data was recorded using a GPS watch and then combined with the UFP data before further analysis with geospatial software (QGIS) along with OpenStreetMap to generate spatial data of personal exposure to UFP. The study revealed significant differences in UFP exposure between motorbike and bus users, with average UFP concentrations of approximately 114,300 and 171,700 particles/cm³ for motorbike users, and 22,600 and 37,200 particles/cm³ for bus users on lines 3 and 4A, respectively. These concentrations exceed WHO guidelines, which consider UFP levels above 20,000 particles/cm³ per hour as high and potentially harmful. The results of our study also revealed varying amounts of exposure on different roadways, with Russian Federation Blvd consistently exhibited the highest concentrations of UFP, especially during periods of peak traffic. Furthermore, indoor environments generally presented lower UFP exposure. Specific activities or events were found to generate temporary increases in particle concentration. It was shown that weekdays had elevated levels of UFP compared to weekends. Regardless of the limitations of the study, especially its small sample size, it provides significant initial observations, highlighting the urgent need for mitigation strategies and further comprehensive studies in the region.

Indoor Emission, Oxidation, and New Particle Formation of Personal Care Product Related Volatile Organic Compounds.

Personal care products (PCPs) contain diverse volatile organic compounds (VOCs) and routine use of PCPs indoors has important implications for indoor air quality and human chemical exposures. This chamber study deployed aerosol instrumentation and two online mass spectrometers to quantify VOC emissions from the indoor use of five fragranced PCPs and examined the formation of gas-phase oxidation products and particles upon ozone-initiated oxidation of reactive VOCs. The tested PCPs include a perfume, a roll-on deodorant, a body spray, a hair spray, and a hand lotion. Indoor use of these PCPs emitted over 200 VOCs and resulted in indoor VOC mixing ratios of several parts per million. The VOC emission factors for the PCPs varied from 2 to 964 mg g-1. We identified strong emissions of terpenes and their derivatives, which are likely used as fragrant additives in the PCPs. When using the PCPs in the presence of indoor ozone, these reactive VOCs underwent oxidation reactions to form a variety of gas-phase oxidized vapors and led to rapid new particle formation (NPF) events with particle growth rates up to ten times higher than outdoor atmospheric NPF events. The resulting ultrafine particle concentrations reach ∼34000 to ∼200000 cm-3 during the NPF events.

Associations between fine particulate matter, gene expression, and promoter methylation in human bronchial epithelial cells exposed within a classroom under air-liquid interface

Associations between indoor air pollution from fine particulate matter (PM with aerodynamic diameter dp < 2.5 μm) and human health are poorly understood. Here, we analyse the concentration-response curves for fine and ultrafine PM, the gene expression, and the methylation patterns in human bronchial epithelial cells (BEAS-2B) exposed at the air-liquid interface (ALI) within a classroom in downtown Rome.Our results document the upregulation of aryl hydrocarbon receptor (AhR) and genes associated with xenobiotic metabolism (CYP1A1 and CYP1B1) in response to single exposure of cells to fresh urban aerosols at low fine PM mass concentrations within the classroom. This is evidenced by concentrations of ultrafine particles (UFPs, dp < 0.1 μm), polycyclic aromatic hydrocarbons (PAH), and ratios of black carbon (BC) to organic aerosol (OA). Additionally, an interleukin 18 (IL-18) down-regulation was found during periods of high human occupancy.Despite the observed gene expression dysregulation, no changes were detected in the methylation levels of the promoter regions of these genes, indicating that the altered gene expression is not linked to changes in DNA methylation and suggesting the involvement of another epigenetic mechanism in the gene regulation.Gene expression changes at low exposure doses have been previously reported. Here, we add the possibility that lung epithelial cells, when singly exposed to real environmental concentrations of fine PM that translate into ultra-low doses of treatment, may undergo epigenetic alteration in the expression of genes related to xenobiotic metabolism.Our findings provide a perspective for future indoor air quality regulations. We underscore the potential role of indoor UFPs as carriers of toxic molecules with low-pressure weather conditions, when rainfall and strong winds may favour low levels of fine PM.

Aircraft Activities and Ultrafine Particle Concentrations near a City Airport: Insights from a Measurement Campaign in Toronto, Canada

Aircraft Activities and Ultrafine Particle Concentrations near a City Airport: Insights from a Measurement Campaign in Toronto, Canada

Review on Sampling Methods and Health Impacts of Fine (PM2.5, ≤2.5 µm) and Ultrafine (UFP, PM0.1, ≤0.1 µm) Particles

Airborne particulate matter (PM) is of great concern in the modern-day atmosphere owing to its association with a variety of health impacts, such as respiratory and cardiovascular diseases. Of the various size fractions of PM, it is the finer fractions that are most harmful to health, in particular ultrafine particles (PM0.1; UFPs), with an aerodynamic diameter ≤ 100 nm. The smaller size fractions, of ≤2.5 µm (PM2.5; fine particles) and ≤0.1 µm (PM0.1; ultrafine particles), have been shown to have numerous linkages to negative health effects; however, their collection/sampling remains challenging. This review paper employed a comprehensive literature review methodology; 200 studies were evaluated based on the rigor of their methodologies, including the validity of experimental designs, data collection methods, and statistical analyses. Studies with robust methodologies were prioritised for inclusion. This review paper critically assesses the health risks associated with fine and ultrafine particles, highlighting vehicular emissions as the most significant source of particulate-related health effects. While coal combustion, diesel exhaust, household wood combustors’ emissions, and Earth’s crust dust also pose health risks, evidence suggests that exposure to particulates from vehicular emissions has the greatest impact on human health due to their widespread distribution and contribution to air pollution-related diseases. This article comprehensively examines current sampling technologies, specifically focusing on the collection and sampling of ultrafine particles (UFP) from ambient air to facilitate toxicological and physiochemical characterisation efforts. This article discusses diverse approaches to collect fine and ultrafine particulates, along with experimental endeavours to assess ultrafine particle concentrations across various microenvironments. Following meticulous evaluation of sampling techniques, high-volume air samplers such as the Chem Vol Model 2400 High Volume Cascade Impactor and low-volume samplers like the Personal Cascade Impactor Sampler (PCIS) emerge as effective methods. These techniques offer advantages in particle size fractionation, collection efficiency, and adaptability to different sampling environments, positioning them as valuable tools for precise characterisation of particulate matter in air quality research and environmental monitoring.

Ultrafine particle measurements in New York State

Measurements of ultrafine particles (UFP) over several years were carried out across seven different locations in New York State. The locations include urban background sites (Queens College and Albany), near road sites (Queens, Buffalo and Rochester) and rural sites (Pinnacle State Park and Whiteface Mountain). UFP at the urban background and near road sites generally show highest concentrations in the morning during the early commute period. Concentrations decrease during the day but increase again in the afternoon or evening period. Weekday concentrations are higher than on weekends. UFP correlates well with traffic related co-pollutants black carbon (BC) and nitrogen oxides (NOx). At the rural locations, UFP concentrations show less variation during the day with highest concentrations in the early afternoon to late evening hours particularly in spring. Seasonally, UFP concentrations across urban background and near road sites, are highest in winter (Dec, Jan, Feb) and lowest in summer (Jun, Jul, Aug). The variation in UFP concentration with temperature, relative humidity and wind speed was investigated. At the Queens College site, particle number concentrations in six different size fractions were measured using a TSI 3031 instrument. Annual average UFP concentrations at Queens College were found to decrease over time consistent with emission control strategies.

Indoor Emissions Contributed the Majority of Ultrafine Particles in Chinese Urban Residences.

Ultrafine particle (UFP) pollution should be controlled to reduce its effects on health. The design of control measures is limited owing to the uncertainty of source contributions in Chinese residences, where indoor UFP pollution is more severe than in Western residences. Herein, a source-specific, time-dependent UFP concentration model was developed by applying an infiltration factor model incorporating coagulation effects. A Monte Carlo framework with the UFP concentration model was employed to estimate the probabilistic distribution of source contributions in Chinese residences. The input parameter distributions were determined based on our survey and previous studies. The annually averaged indoor UFP concentration was estimated at (2.75 ± 1.71) × 104 #/cm3, ranging from 2.35 × 103 to 1.27 × 105 #/cm3 outside the kitchen, and at (5.48 ± 3.08) × 104 #/cm3, ranging from 2.90 × 103 to 1.94 × 105 #/cm3 in the kitchen. Indoor sources contributed more to indoor UFPs, accounting for 61% in the nonkitchen and 80% in the kitchen, surpassing their contribution to indoor PM2.5 in Chinese residences. Meanwhile, the indoor UFP emission contributions were higher than those in the United States, Canada, and Germany, owing to higher emissions from cooking and cigarette smoking. These results will aid in elucidating human exposure to UFPs and in designing more targeted control measures.

Effects of gamma radiation on the optical properties of ultrafine iron particle/polystyrene composites

The present research studied the influence of gamma radiation doses on the optical properties and parameters of the tested composite samples consisting of polystyrene polymer as a matrix filled with different concentrations of ultrafine iron particles (0, 10, 20, and 30 wt.%) with an average thickness of 2 µm. Using a UV-1800 Shimadzu spectrophotometer, the optical absorbance and transmittance values of the tested composite samples were measured at room temperature in the wavelength range of 200–800 nm. Optical parameters such as the excitation energy for electronic transitions, optical energy gap, dispersion energy, static dielectric constant, static refractive index, moments of the optical spectrum, optical oscillator strengths, linear optical susceptibility, third-order nonlinear optical susceptibility, carrier concentration to the effective mass ratio, high-frequency dielectric constant, nonlinear refractive index, plasma frequency and long wavelength refractive index were calculated and discussed at different doses of gamma radiation (1, 2, and 6 kGy). The results demonstrate that the optical properties and parameters of the gamma-irradiated composites vary with increasing gamma doses. This variation in values was observed after increased irradiation due to enhanced metal–polymer bonding and due to an increase in the density of the free charges within the metal polymer composites.

Fine Particle Formation and Dependence of Wet Deposition on Precipitation Intensity in an Urban Area

ABSTRACT In order to understand the characteristics of the change of aerosol concentration in an urban area and the impact of meteorological conditions on aerosol concentration in urban areas, particle concentration and size distribution were measured using an aerosol particle counter and an aerosol spectrometer in Hefei, China in spring 2017. Meteorological data, such as temperature, relative humidity, wind speed, wind direction, and shortwave radiation, were measured on a meteorological tower. The concentration of coarse mode (d > 2.5 μm, d is particle diameter), accumulation mode (0.25 μm<d < 2.5 μm), and ultrafine (Aitken and nucleation mode, d < 0.25 μm) particles under different meteorological conditions were recorded. Results show that, approximately 10–20 min after the solar downward shortwave radiation decreases (rises), the ultrafine particles (UFPs) concentration decreases (rises). Diurnal change in radiation causes daily change in the concentration of UFPs, and when the relative humidity was low, UFP generation easily occurs. On wet deposition, the concentration of coarse mode particles is significantly reduced during precipitation, and the concentration of accumulation mode particles varies during heavy precipitation and slight precipitation. Because of the combined action of wet deposition and hygroscopic growth, the concentration of accumulation mode particles first increases and then decreases. And during the slight precipitation, the concentration only increases with the relative humidity.

Determination of Occupational Exposure to Ultrafine Particles in Different Sectors of Activity

The primary sources of ultrafine particulate matter are linked to human activity. Certain particulate emissions, particularly those of a finer nature, can significantly impact human health, making them one of the most concerning pollutants. Ultrafine particles (UFPs), which have a diameter of less than 100 nm, are of particular concern due to their impact on human health and the difficulty in controlling them. The concentration of ultrafine particles (UFPs) in the workplace is a growing concern and is classified as an emerging risk. Workers may be exposed to UFPs through inhalation, skin absorption, ingestion, or a combination of these routes. This study aims to determine the levels of UFP exposure among workers in environments with varying direct particle emission patterns. Measurements were conducted to compare the results with the levels recommended by the WHO. The study monitored industrial workplaces with direct particulate matter emissions, such as a carpentry workshop and a bakery, as well as social sector sites without or almost without direct particle emissions, such as a school and a health clinic. One conclusion drawn from this study is that all tasks and occupations are susceptible to high levels of UFPs, exceeding WHO recommended values in virtually all monitored environments. Therefore, monitoring and controlling UFPs is crucial. Further in-depth studies on this subject are also necessary.

Health risk assessment of ultrafine particle movement in children's residential spaces based on probabilistic neural networks

The air quality in children's living spaces has a significant impact on their health, and ultrafine particulate matter (PM2.5), as one of the main pollutants in the air, poses a particularly prominent threat to children's respiratory and immune systems. Therefore, it important to conduct health risk assessment on ultrafine particle exercise in children's living spaces. In this article, an intelligent risk assessment model of ultrafine atmospheric particles in children's sports space in residential areas based on probabilistic neural network (PNN) is studied. This model utilizes probabilistic neural networks to monitor and predict ultrafine particles in residential spaces, evaluating their potential risks to children's health. By collecting relevant data such as particulate matter concentration and air quality index in residential spaces, and using probabilistic neural networks for training and prediction, accurate assessment of the health risks of ultrafine particulate matter during exercise can be achieved. This model can be applied to densely populated places such as families and schools, providing parents and relevant institutions with scientific risk warning and prevention measures to ensure the health and safety of children. Probabilistic neural networks can learn and simulate complex nonlinear relationships, making the model more accurate in predicting the concentration of ultrafine particles and health risks. So as to construct a method system of health risk assessment of atmospheric particles, and the model is heavy metal elements in atmospheric fine particles, and corresponding improvement measures are put forward according to the assessment results. For circulatory system diseases, the degree of harm of atmospheric temperature and fine particles to children's health is basically close, and with the continuous decline of temperature, the synergistic effect of the two is more obvious. The concentration of atmospheric ultrafine particles significantly affects the health risk of children's sports activities space. All the experiments in this article are quite good. Among them, the average accuracy of the PNN health risk identification model is 0.840, and the average recall rate is 0.837. The health risk assessment model in this article strengthens the correlation of data information through scientific methods, grasps the basic information of children's sports activity spaces in residential areas, and formulates targeted sports health risk assessments for children's sports activity spaces in residential areas. Compared with the comparison method, the response speed is significantly improved, with an accuracy rate of over 90%.

Spatial and temporal variation of cooking-emitted particles in distinct zones using scanning mobility particle sizer and a network of low-cost sensors

Exposure to ambient and household fine-particulate matter is identified as a substantial contributor to premature mortality in India, according to the Global Burden of Disease Studies. This study examines the impacts of typical Indian cooking practices on indoor air quality characteristics by monitoring the evolution of fine and ultrafine particle (UFP) concentration in the dining facility of a residential educational institute in India. The monitoring area was spread across the kitchen (zone 1) and the dining hall (zone 2). A combination of validated low-cost PM sensors (LCS), DustTrak8433, and Scanning Mobility Particle Sizer (SMPS) was utilized for real-time data acquisition while using Liquefied Petroleum Gas (LPG) as the cooking fuel. PM2.5 and UFP concentrations were monitored at 1.3 m and 1.8 m from the floor to assess the vertical variation of pollutants during cooking activities, including breakfast, lunch, and dinner, and processes such as preheating, reheating, stir-frying, and deep-frying. It was found that the prolonged cooking durations involved in high-heat cooking methods like stir-frying and deep-frying resulted in a rise in coarser UFP (300–550 nm) and PM2.5, causing a higher exposure to PM and UFP concentration. PM2.5 levels are higher at upper heights during typical cooking processes because of temperature-driven convection currents and hygroscopic growth of particles due to high humidity levels. Air exchange rates (AER) considerably varied by using chimneys and were low during the controlled (closed doors) compared to mixed ventilation (opened doors) conditions. The maximum AER was obtained during lunch (4.3–9.9 h−1) compared to breakfast (-7.8–6.8 h−1) and dinner (0.55–7.9 h−1). The decrement rate of PM2.5 inside zone 1 was highest during lunch (126 µgm−3 h−1), coinciding with the highest AER during mixed ventilation. It is recommended that improving ventilation and better design of the kitchen can reduce the exposure of PM and UFP in commercial and rural area kitchens.