Levels Of Fine Particles Research Articles

Air Pollution and the Prevalence of Keratoconus: Is There a Connection?

ABSTRACT Purpose Keratoconus is a progressive, asymmetrical corneal ectasia with multifactorial origin. Three identified risk factors for keratoconus include exposure to ultraviolet (UV) rays, eye rubbing, and atopy. Other factors like pollution would play a role in the physiopathology of keratoconus. In this study we investigate the effects of particles matter (PM) of 2.5 and 10 μm, but also nitrogen dioxide (NO2) and the correlation with the prevalence in the scientific literature. Method A literature review was performed using four databases (PubMed, Research gate, Google scholar and International Journal of Keratoconus and Ectatic Corneal Diseases) according to strict selection criteria. Levels of fine particles and nitrogen dioxide were extracted from available World Health Organization (WHO) databases and correlated with prevalences from epidemiological studies. Results The mean pollution rate in the selected studies was 26.88 ± 25.26 μg/m3 for PM2.5 , 58.23 ± 60.98 μg/m3 for PM10 and 24.79 ± 12.58 μg/m3 for NO2. Pearson correlation tests revealed a significant positive correlation between prevalence of keratoconus with particles rate of PM2.5 (R = 0.58; p < 0.001), PM10 (R = 0.67; p < 0.001) and NO2 (R = 0.64; p = 0.00016). Conclusion Fine particles appear to be a risk factor for keratoconus. These pollutants may act indirectly by exacerbating known risk factors such as atopy and eye rubbing. Atmospheric pollution may also have a direct effect on the cornea, by disturbing the structure of the epithelium and increasing cell apoptosis.

Multiple Environmental Exposures and the Development of Hypertension in a Prospective US-Based Cohort of Female Nurses: A Mixture Analysis.

We investigated the independent and joint associations between multiple environmental exposures and incident hypertension in a US nationwide prospective cohort of women: the Nurses' Health Study II. We followed 107,532 nonhypertensive participants from 1989 to diagnosis of hypertension, loss to follow-up, death, or end of follow-up in June 2019. We applied Cox proportional hazards models to assess associations of incident hypertension with time-varying residential exposure to air pollution, noise, surrounding greenness, temperature, and neighborhood socioeconomic status (nSES), adjusting for potential confounders and coexposures. We evaluated the joint association of simultaneous exposure using quantile g-computation. We observed 38,175 hypertension cases over 2,062,109 person-years. Increased hypertension incidence was consistently associated with lower nSES and higher levels of fine particles (PM2.5) and nighttime noise exposures: hazard ratio (HRs) and 95% confidence intervals (CIs) of 1.06 (1.04, 1.08), 1.04 (1.01, 1.07), and 1.01 (1.00, 1.03), respectively, per interquartile range change. Joint HR for a one-quartile change in simultaneous exposure to the mixture was 1.05 (95% CI: 1.02, 1.09), assuming additivity, or 1.13 (95% CI: 1.06, 1.20), considering potential interactions within the mixture. Hypertension prevention should focus on enhancing nSES and reducing PM2.5 and noise levels, recognizing that reducing the overall exposures may yield additional benefits.

Study on the Performance of Asphalt Modified with Bio-Oil, SBS and the Crumb Rubber Particle Size Ratio.

To enhance the properties of SBS and crumb rubber-modified asphalts, four different amounts (5%, 10%, 15%, and 20%) of castor oil were added to crumb rubber-modified asphalts to mitigate the adverse effects of high levels of fine crumb rubber particles on the aging resistance of SBS and crumb rubber-modified asphalt. Initially, a conventional test was conducted to assess the preliminary effects of bio-oil on the high-temperature and anti-aging properties of SBS and crumb rubber-modified asphalt. Subsequently, dynamic shear rheometer and bending beam rheometer tests were employed to evaluate the impact of bio-oil on the high- and low-temperature and anti-fatigue properties of SBS and crumb rubber-modified asphalt. Finally, fluorescence microscopy and Fourier transform infrared spectroscopy were used to examine the micro-dispersion state of the modifier and functional groups in bio-oil, SBS and crumb rubber composite-modified asphalts. The experimental results indicated that bio-oil increased the penetration of SBS and crumb rubber-modified asphalt, decreased the softening point and viscosity, and significantly improved its aging resistance. The addition of bio-oil enhanced the anti-fatigue properties of SBS and crumb rubber-modified asphalt. The optimal amount of added bio-oil was identified. Bio-oil also positively influenced the low-temperature properties of SBS and crumb rubber-modified asphalt. Although the addition of bio-oil had some adverse effects on the asphalt's high-temperature properties, the asphalt mixture modified with bio-oil, SBS, and crumb rubber still exhibited superior high-temperature properties compared to unmodified asphalt. Furthermore, fluorescence microscopy and Fourier transform infrared spectroscopy results demonstrated that bio-oil can be uniformly dispersed in asphalt, forming a more uniform cross-linked structure and thereby enhancing the aging resistance of SBS and crumb rubber-modified asphalt. The modification process involved the physical blending of bio-oil, SBS, and crumb rubber within the asphalt. Comprehensive research confirmed that the addition of bio-oil has a significant and positive role in enhancing the properties of SBS and crumb rubber-modified asphalt with different composite crumb rubber particle size ratios.

OCCURRENCE OF PM0.1 AND PM2.5 AT HIGH POLLUTING EVENT DAYS IN HANOI AND HEALTH IMPLICATION

High levels of fine (PM2.5) and ultrafine (PM0.1) particles in the atmosphere can cause adverse effects on the environment and human health. This study aims at determining the mass concentrations of PM and health risks on pollution event days (episodes) in Hanoi. Semi-daily samples (daytime and night-time) of PM2.5 and PM0.1 were collected at Hanoi University of Science and Technology, in December 2021. The daily PM2.5 concentrations were in the range of 42 – 204 µg/m3 (average of 123 µg/m3). Those of PM0.1 varied from 9 to 30 µg/m3 (average of 22 µg/m3). There is negligible change on daytime and night-time PM0.1 concentrations, whereas those levels of PM2.5 were remarkably different. PM2.5 daytime concentrations were in the range of 39 – 205 µg/m3 with an average of 107 µg/m3. The level ranges of night-time were slightly wider which varied from 39 to 230 µg/m3 (average of 132 µg/m3). A prolonged episode of PM2.5 (which is defined by the criterion of PM2.5 &gt; 50 µg/m3) was found with an intensity of 26 days in December. During the pollution episode, the Monte Carlo simulation showed that respirable doses were the highest for the adult (above 21 years) for chronic effects, whereas the highest doses for acute were observed in the children (0-3 years), which has implications in the adverse health effects for sensitive groups. The sensitive analysis finds the concentration of PM to be the most influencing factor in inhalation dose estimation.

Quantification and Characterization of Fine Plastic Particles as Considerable Components in Atmospheric Fine Particles.

The negative effects of air pollution, especially fine particulate matter (PM2.5, particles with an aerodynamic diameter of ≤2.5 μm), on human health, climate, and ecosystems are causing significant concern. Nevertheless, little is known about the contributions of emerging pollutants such as plastic particles to PM2.5 due to the lack of continuous measurements and characterization methods for atmospheric plastic particles. Here, we investigated the levels of fine plastic particles (FPPs) in PM2.5 collected in urban Shanghai at a 2 h resolution by using a novel versatile aerosol concentration enrichment system that concentrates ambient aerosols up to 10-fold. The FPPs were analyzed offline using the combination of spectroscopic and microscopic techniques that distinguished FPPs from other carbon-containing particles. The average FPP concentrations of 5.6 μg/m3 were observed, and the ratio of FPPs to PM2.5 was 13.2% in this study. The FPP sources were closely related to anthropogenic activities, which pose a potential threat to ecosystems and human health. Given the dramatic increase in plastic production over the past 70 years, this study calls for better quantification and control of FPP pollution in the atmosphere.

Contributions of Biomass Burning and Other Sources to Fine Particle Level and Oxidative Potential in Suburban Tokyo, Japan

Contributions of Biomass Burning and Other Sources to Fine Particle Level and Oxidative Potential in Suburban Tokyo, Japan

Effects of grain processing (cracked vs. steam-flaked) and forage sources (alfalfa hay and wheat straw) as a free-choice provision on growth performance, rumen fermentation, blood metabolites, and behavior of dairy calves

The aim of this study was to investigate the interaction between physical form of starter (PFS) and forage source (FS) with free access to forage on feed intake, growth performance, rumen fermentation, blood metabolites and behavioral traits of dairy calves. A total of 48 7-day-old Holstein calves were randomly assigned to one of four treatments in a 2 × 2 factorial arrangement, with FS [alfalfa hay (AH) and wheat straw (WS)] as free-choice supply and PFS diets (cracked vs. steam-flaked) as main effects. Feeding treatments included (1) starter diet with steam flaked corn (SFC) and free access to AH (SFC-AH), (2) starter diet with SFC and free access to WS (SFC-WS), (3) starter diet with cracked corn (CRC) and free access to AH (CRC-AH) and (4) starter diet with CRC and free access to WS (CRC-WS). The calves were weaned on day 58 and remained in the experiment until day 70. All calves had free access to water and starter feed. The results showed that there was no interaction between PFS and FS in terms of starter intake, forage intake, dry matter intake (DMI), average daily gain (ADG), body weight (BW) or feed efficiency (FE). Calves fed CRC consumed more dry matter, TMR and forage than calves fed SFC diets. Regardless of the PFS diet, weaning weight, total weight and total ADG were higher in calves fed WS, while forage intake was higher in calves fed AH. Calves fed CRC-AH had the lowest rumen pH at day 68 compared to the other groups (except SFC-WS at day 70). An interaction between PFS diets and FS affected rumen proportion of propionate on day 35, since calves, which were fed CRC-AH had the highest molar percentage of propionate than calves fed other diets (except for SF-WS). At day 65, calves fed SFC starter feed had higher plasma glucose concentrations than calves fed CRC. It was found that PFS feed and FS had an interaction effect on BUN at day 65, with calves fed CRC-AH having the highest BUN. Compared to the other groups, calves fed CRC-WS had the highest BHB at day 33 and throughout the period (days 35 and 65). An interaction between PFS diets and FS affected lying time and forage eating time, with CRC-AH calves exhibiting the longest lying time and lowest forage eating time. The time spent on NNOB tended to be longer in SFC-fed calves than in CRC-fed calves, regardless of the forage source. Compared to calves fed SFC, calves fed CRC with high levels of fine particles consumed more dry matter, TMR, and forage while spending less time on NNOB. Furthermore, feeding calves chopped WS instead of AH increased weaning weight, total weight, and total ADG, although forage intake was higher in calves fed AH. In summary, a combination of cracked corn starter with free access to wheat straw appears to provide the best growth outcomes for dairy calves.

Critical windows of greenness exposure during preconception and gestational periods in association with birthweight outcomes

Few studies have examined the association between greenness exposure and birth outcomes. This study aims to identify critical exposure time windows during preconception and pregnancy for the association between greenness exposure and birth weight. A cohort of 13 890 pregnant women and newborns in Shanghai, China from 2016–2019 were included in the study. We assessed greenness exposure using Normalized Difference Vegetation Index (NDVI) during the preconception and gestational periods, and evaluated the association with term birthweight, birthweight z-score, small-for-gestational age, and large-for-gestational age using linear and logistic regressions adjusting for key maternal and newborn covariates. Ambient temperature, relative humidity, ambient levels of fine particles (PM2.5) and nitrogen dioxide (NO2) assessed during the same period were adjusted for as sensitivity analyses. Furthermore, we explored the potential different effects by urbanicity and park accessibility through stratified analysis. We found that higher greenness exposure at the second trimester of pregnancy and averaged exposure during the entire pregnancy were associated with higher birthweight and birthweight Z-score. Specifically, a 0.1 unit increase in second trimester averaged NDVI value was associated with an increase in birthweight of 10.2 g (95% CI: 1.8–18.5 g) and in birthweight Z-score of 0.024 (0.003–0.045). A 0.1 unit increase in an averaged NDVI during the entire pregnancy was associated with 10.1 g (95% CI: 1.0–19.2 g) increase in birthweight and 0.025 (0.001–0.048) increase in birthweight Z-score. Moreover, the associations were larger in effect size among urban residents than suburban residents and among residents without park accessibility within 500 m compared to those with park accessibility within 500 m. Our findings suggest that increased greenness exposure, particularly during the second trimester, may be beneficial to birth weight in a metropolitan area.

Characterization of Chemical Components and Optical Properties of Toluene Secondary Organic Aerosol in Presence of Ferric Chloride Fine Particles

Iron ion is the common transition metal ion in atmospheric aerosol, which can affect the components and optics of secondary organic aerosol (SOA). In the current study, the atmospheric photooxidation of toluene to produce SOA in the presence of ferric chloride fine particles is simulated in a smog chamber; on-line and off-line mass spectrometry and spectroscopic instruments are used to characterize constituents and optics of SOA. Compare with SOA formed in the absence of fine particles, the laser desorption/ionization mass spectra of toluene SOA generated in the presence of ferric chloride fine particles show ion peaks of m/z = 163 and 178, the UV-Vis spectra of the extracting solution for toluene SOA have peaks near 400 and 700 nm, and the electrospray ionization mass spectra contain peaks at m/z = 248 and 300. Based on this spectral information, it is shown that gaseous methylcatechol formed from photooxidation of toluene may react with iron ion on the surface of fine particles by complexing and oxidation–reduction, resulting in methylbenzoquinone products and metallo-organic complex ions such as [Fe(III)(CH3C6H3OO)]+, [Fe(III)(CH3C6H3 OO)2]− and [Fe(III)(CH3C6H3OO)Cl2]−. These products have strong light absorption ability, resulting in an increase in the averaged mass absorption coefficient (&lt;MAC&gt;) in the 200~1000 nm range and the MAC at 365 nm (MAC365) for toluene SOA, while &lt;MAC&gt; and MAC365 progressively increase with an increasing concentration of ferric chloride fine particles. These results serve as experimental references for the study of the formation mechanism and optical properties of metallo-organic complexes in atmospheric aerosol particles in regions experiencing high levels of fine particles of metal and automobile exhaust pollution.

Concentrations of PM0.1 and PM2.5 at high polluting event days in Ha Noi and the effects of meteorological conditions

. High levels of fine (PM2.5) and ultrafine (PM0.1) particles in the atmosphere can cause adverse effects on the environment and human health. This study aims at determining the mass concentrations of PM and meteorological influencing factors in high pollution event days in Hanoi. Daily samples of PM2.5 and PM0.1 were collected at a mixed site in Hanoi, Vietnam, from the middle of October to December 2020. High pollution events were determined based on PM2.5 concentrations and analyzed for its average concentration and intensity (number of days). The regression analysis and correlation matrix were determined by R software, version 4.04. Seven high pollution events were recorded for 2.5 sampling months. The daily PM2.5 concentrations were in the range of 19 - 147 µg/m3. Those of PM0.1 varied from 2 to 13 µg/m3 with an average of 6 µg/m3. The investigated meteorological factors can explain 70% PM2.5 variation but only 47% of PM0.1 variations.

Distribution and the trend of airborne particles and bio-aerosol concentration in pediatric intensive care units with different ventilation setting at two hospitals in Riyadh, Saudi Arabia

ObjectiveTo examine the distribution and the trend of airborne particles and bio-aerosol concentration in pediatric intensive care units (PICUs) in two tertiary care hospitals with different ventilation setting. MethodsHospitals A but not B is provided with a central HEPA filter. PICUs in both hospitals were categorized into protective environment (PE) with room HEPA filter, semi-protective environment (SPE) with portable air-purifier, and non-protective environment (NPE) with neither system. Fine particles (≤ 2.5 µm) and coarse particles (≤ 10.0 µm) were obtained using optical particle counter (Lighthouse Handheld 3016) and total bacterial (TBC) and fungal (TFC) counts were obtained using Andersen air sampler. ResultsHospital B had significantly higher levels of fine and coarse particles (in all room), TBC (in PE), but not TFC compared with matched rooms in hospital A. In hospital B, the levels of fine particles, coarse particles, and TBC were lowest in SPE (p < 0.001, p = 0.004, and p = 0.006, respectively) while TFC was lowest in NPE (p = 0.014). Airborne particles, TBC, and TFC had variable trends with some of the indoor peaks follow outdoor peaks. Gram-positive bacteria (69 %) were the predominant bacteria in hospital A while bacterial flora (70 %) were the predominant bacteria in hospital B (p < 0.001 for each). ConclusionsThe levels of airborne contaminants and microbial counts in PICUs are significantly affected by the ventilation system and to less extent by outdoor levels. The results indicated that advanced filtration system and central HEPA filters play a significant role in the reduction of indoor fine particulates and TBC.

Environmental Risk Assessment from 2018 To 2022 for Kota, Rajasthan (India)

Particulate matter pollution in the metropolis has become an international concern because of its dangerous short and long-term effects on humans and the environment. This research aims to quantify particulate matter's severe impact on inhabitants and identify the ecological environment risk category of Kota city, Rajasthan (India), throughout the selected study period from 2018 to 2022 for four years. Human health risk assessment has been assessed through AirQ+ software (WHO invented), while ecological hazard risk categories were recognised through risk quotient (RQ). The present scenario of particulate matter concentration is compared with standards given by different regulating agencies (WHO, USEPA, and Indian NAAQS) to verify particulate matter pollution. The current particulate matter concentration levels of Kota city are also compared with different regional cities of Rajasthan (India), namely, Jaipur, Udaipur, Ajmer, Pali, Alwar, and Jodhpur. The dust ratio (PM2.5/PM10) is computed for Kota and regional cities to validate the increasing levels of fine particulates than the larger ones. The four-year average concentration of PM10 and PM2.5 were 121 and 58 µg/m3, respectively, with a dust ratio of 0.48. Particulate matter concentrations (PM10 and PM2.5) are violating the standards set by environmental agencies during the study period. The mean risk quotient (RQ) is 2.02 for PM10 and 1.43 for PM2.5, which implies a high-risk hazard category (RQ &gt; 1) in the ecological environment of Kota city. The mortality cases evaluated from AirQ+ software were 5024 for all natural causes, 885 for lung cancer, 272 for acute lower respiratory infection, 464 for COPD, 2060 for IHD, and 1880 for stroke. The number of hospital admissions was 1485 for respiratory disease, 58 for cardiovascular disease, and 784 for adult mortality (30+ years) to PM2.5. Chronic bronchitis incidence in adults was 14469, postneonatal infant mortality was 355816, and the prevalence of bronchitis in children was 767 due to PM10 exposure for a long time, while asthma symptoms in asthmatic children were 349 due to exposure for a short time. The results of this study are terrifying, and it is an earlier sign to government representatives and stakeholders to implement the new policies and technologies to curb the pollution level originating from particulate matter; otherwise, impacts on the environment become more acute.

P19-13 Levels of fine and ultrafine particles in firefighters’ personal protective equipment storage rooms

P19-13 Levels of fine and ultrafine particles in firefighters’ personal protective equipment storage rooms

Chemical composition, oxidative potential and identifying the sources of outdoor PM2.5 after the improvement of air quality in Beijing.

Air pollution poses a serious threat to human health. The implementation of air pollution prevention and control policies has gradually reduced the level of atmospheric fine particles in Beijing. Exploring the latest characteristics of PM2.5 has become the key to further improving pollution reduction measures. In the current study, outdoor PM2.5 samples were collected in the spring and summer of Beijing, and the chemical species, oxidative potential (OP), and sources of PM2.5 were characterized. The mean PM2.5 concentration during the entire study period was 41.6 ± 30.9μgm-3. Although the PM2.5 level in summer was lower, its OP level was significantly higher than that in spring. SO42-, NH4+, EC, NO3-, and OC correlated well with volume-normalized OP (OPv). Strong positive correlations were found between OPv and the following elements: Cu, Pb, Zn, Ni, As, Cr, Sn, Cd, Al, and Mn. Seven sources of PM2.5 were identified, including traffic, soil dust, secondary sulfate, coal and biomass burning, oil combustion, secondary nitrate, and industry. Multiple regression analysis indicated that coal and biomass combustion, industry, and traffic were the main contributors to the OPv in spring, while secondary sulfate, oil combustion, and industry played a leading role in summer. The source region analysis revealed that different pollution sources were related to specific geographic distributions. In addition to local emission reduction policies, multi-provincial cooperation is necessary to further improve Beijing's air quality and reduce the adverse health effects of PM2.5.

Machine Learning Models to Predict Critical Episodes of Environmental Pollution for PM2.5 and PM10 in Talca, Chile

One of the main environmental problems that affects people’s health and quality of life is air pollution by particulate matter. Chile has nine of the ten most polluted cities in South America according to a report presented in 2019 by Greenpeace and AirVisual that measured the air quality index based on the levels of fine particles. Most Chilean cities are highly contaminated by particulate matter, especially during the months of April to August (the critical episode management period). The objective of this study is to predict particulate matter levels based on meteorological and climatic features, such as temperature, wind speed, wind direction, precipitation and relative air humidity in Talca, Chile, during the critical episode management periods between 2014 and 2018. Predictive models based on machine learning techniques were used, considering training datasets with meteorological and climatic data, and particulate matter levels from the three air quality monitoring stations in Talca, Chile. We carried out the training of 24 models to predict particulate matter levels considering the 24-h average and average between 05:00 to 11:00 p.m. For the model testing, data from the year 2018 during the critical episode management period were used. The obtained results indicate that our models are able to effectively predict levels of particulate matter, enabling correct management of critical episodes, especially for alert, pre-emergency and emergency conditions. We used the cross-platform and open-source programming language Python for the development and implementation of the proposed models and R-project for some visualizations.

Evaluating health outcome metrics and their connections to air pollution and vulnerability in Southern California's Coachella Valley

The ongoing desiccation of California's Salton Sea has led to increasing concerns about air quality and health for its surrounding communities, including the nearby Coachella Valley – a region already experiencing severe air quality and health disparities. Here we explore spatial air pollution and human health disparities in the Coachella Valley with particular attention to disparities arising across population characteristics including both socioeconomic and demographic vulnerabilities. We use two different measures of respiratory and cardiovascular health outcomes at the individual and census tract levels – one measure based on a randomly sampled telephone survey and the other measure based on emergency room visitation data – to investigate the degree to which these health outcomes are connected to air pollution and socioeconomic metrics. We further investigate biases and differences between the health outcome metrics themselves and suggest opportunities to address them in future analyses and survey efforts. We find that more vulnerable communities are associated with higher levels of fine particulates, but lower levels of ozone. While emergency visit rates show a significant positive correlation with both pollutants, no such association is found when using surveyed health outcome data. The ratio of emergency visits versus survey rates shows a positive relationship with socioeconomic and demographic vulnerability, indicating that vulnerable communities are less likely to self-report diagnoses despite higher rates of respiratory or cardiovascular hospitalization. Additionally, survey respondents tend to show less vulnerability relative to their surrounding census-based demographics. These findings suggest the need for greater attention to health issues specifically within disadvantaged communities in the Coachella Valley, building upon and working within existing community networks and local resources, to better address current and projected health needs. Our findings also highlight disparities in air pollution exposure, health outcomes, and population characteristics in the Coachella Valley, providing context for crucial pollution reduction efforts in the face of increasing environmental threats.

Analysis of Lateritic Soil Reinforced with Palm Kernel Shells for Use as a Sub-Base Layer for Low-Traffic Roads

In tropical areas, palm oil production generates significant amounts of waste, including palm kernel shells. The use of this waste in the civil engineering sector, presents a very challenging task. In the present study, the production of lateritic soil (A-2 in GTR classification and A-7-6 (9) in HRB classification) reinforced with palm kernel shells is considered. In order to improve their performances, these materials are mixed using the Fuller’s parabolic law. Moreover, experimental tests are used to characterize the physical and mechanical geotechnical properties of the lateritic soil. After characterizing the matrix (i.e., lateritic soil) and the inclusions (i.e., palm kernel shells) in their natural state, it is found that Avrankou’s lateritic soil has a high level of fine particles (56.6%), high plasticity (PI = 21%) and low lift (ICBR = 17%); which makes it unusable in the pavement layer. Results also prove that the mixture composed of 39% of lateritic soil volume and 61% of PKS with a CBR index equals to 30 and the mixture composed of 45% of lateritic soil, 40% PKS and 15% of lagoon sand with a CBR index equals to 41 can be used as sub-base layer for roads for low and medium traffic, respectively.

Air pollution in the operating room: A case study of characteristics of airborne particles, PAHs and environmentally persistent free radicals

Air quality in the microenvironment of operating rooms (ORs) has attracted much attention as surgical smoke may pose health risks. We investigated air pollution in the operating room with a laminar flow system by examining the number and size distribution of airborne particles, the chemical composition and morphology of single particles, and polycyclic aromatic hydrocarbons (PAHs). In addition, environmentally persistent free radicals (EPFRs) in ORs are reported for the first time. The results showed that there were high levels of fine particles, EPFRs, and PAHs in laminar flow operating rooms during surgical procedures. PM2.5 is the dominant particle in ORs (accounting for >90%), consisting mainly of calcareous and metal-related particles based on the morphology and chemical analysis of single particles. In addition, anesthetic gas-related particles were found in the fine particles, and their toxicology requires more attention. EPFRs in the ORs were mainly carbon-centered radicals that may be reactive to cells. The concentrations of EPFRs and PAHs in ORs were higher than in the outside environment and present a potential health risk to surgeons and anesthetists. Hence, effective filtration and evacuation of surgical smoke are necessary.

The coast is clear: Shipping emission standards, air quality and infant health

This study explores the stricter cap on the sulfur content in marine fuel implemented in seas in north-western Europe in 2015. The analysis is built on a difference-in-differences design that compares outcomes in coastal areas before and after the tightening of the sulfur cap, to the outcomes in control areas over the same period. The results show that the new sulfur cap reduced annual average ambient concentrations of sulfur dioxide ( S O 2 ) in coastal areas by 22 percent and levels of fine particulate matter (PM2.5) by 6 percent, compared to control areas. In the subsample with available air quality readings, the sulfur cap led to a 7 percent reduction in the risk of low birthweight in coastal areas. The estimated improvements provide a benchmark for assessing the benefits of tightening sulfur standards in other settings. • Cap on sulfur content in marine fuel tightened in 2015. • Stricter cap reduced concentrations of sulfur dioxide by 22 percent. • Stricter cap reduced levels of fine particles by 6 percent. • Stricter cap reduced risk of low birthweight by 7 percent in a subsample.

Estimations of ambient fine particle and ozone level at a suburban site of Beijing in winter

Estimates of PM2.5 and O3 in suburban areas are of importance for assessing exposure risk and epidemiological studies of air pollution where large scale and long-term measurements network are absent. To fulfill this goal, our study develops a flexible approach to predict levels of PM2.5 and O3 at a suburban site of Beijing using multilayer perceptron (MLP) neural network analysis with the inputs of gaseous air pollutants (CO, SO2, NO, and NO2) and meteorological parameters (wind direction, wind speed, temperature, pressure and humidity). Daily ambient data of PM2.5, O3, PM10, CO, SO2, NO, and NO2 were estimated using hourly data collected from January 20 to March 10 in the years from 2016–2020 at a suburban site of Beijing, respectively. Ambient measured levels of PM2.5 and O3 were compared with the output estimates of PM2.5 and O3 through MLP neural network analysis with limited input variables. Overall, MLP neural network analysis could explain 97% of measured PM2.5 mass and 82% of measured O3 level with R2 values of 0.983 and 0.905, respectively. This approach could be helpful for reconstruct historical PM2.5 and O3 levels in suburban areas.