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Ambient particles contribute to occupant exposure as they infiltrate indoor environments through building envelope cracks, impacting indoor air quality. This study investigates the impact of indoor air humidity on the infiltration of ambient particles, highlighting humidity's crucial role in influencing particle dynamics in indoor environments. Employing a controlled chamber system, we conducted experiments to quantify the infiltration of size-resolved particles under varying relative humidity (RH) conditions. Both the total number and the mass concentration of particles increased with RH in the experimental chamber. The smallest particles (0.3–0.4 μm) experienced reduced infiltration at higher RH levels due to hygroscopic growth, while intermediate-sized particles showed increased infiltration, resulted from coagulation effects. Large particles (>1.0 μm) demonstrated reduced infiltration factors, caused by lower penetration and higher deposition rates, with minimal impact from RH changes. Our findings reveal that RH influences particle hygroscopic growth, deposition rate, and coagulation process, thereby affecting indoor particle size distribution and concentration. [ABSTRACT FROM AUTHOR]

Ambient particles contribute to occupant exposure as they infiltrate indoor environments through building envelope cracks, impacting indoor air quality. This study investigates the impact of indoor air humidity on the infiltration of ambient particles, highlighting humidity’s crucial role in influencing particle dynamics in indoor environments. Employing a controlled chamber system, we conducted experiments to quantify the infiltration of size-resolved particles under varying relative humidity (RH) conditions. Both the total number and the mass concentration of particles increased with RH in the experimental chamber. The smallest particles (0.3–0.4 μm) experienced reduced infiltration at higher RH levels due to hygroscopic growth, while intermediate-sized particles showed increased infiltration, resulted from coagulation effects. Large particles (>1.0 μm) demonstrated reduced infiltration factors, caused by lower penetration and higher deposition rates, with minimal impact from RH changes. Our findings reveal that RH influences particle hygroscopic growth, deposition rate, and coagulation process, thereby affecting indoor particle size distribution and concentration.

To investigate the causative component for certain health outcomes, the associations between the properties of ambient particles and cause-specific mortality (all-cause, cardiovascular, and respiratory-related mortality) measured in Seoul, Korea, from January 1, 2013, to December 31, 2016, were evaluated with a quasi-Poisson generalized additive model (GAM). The total mass of PM10 and PM2.5 moderately affected respiratory-related mortality but had almost no impact on all-cause and cardiovascular-related mortality. Among PM2.5 mass compositions, ammonium sulfate, which is in generally 300–500 nm as a secondary species, showed the most statistically significant effect on respiratory-related mortality at lag 4 (p < 0.1) but not for other mortalities. However, from the size-selective investigations, cardiovascular-related mortality was impacted by particle number concentrations (PNCs), particle surface concentrations (PSCs), and particle volume concentrations (PVCs) in the size range from 50 to 200 nm with a statistically significant association, particularly at lag 1, suggesting that mass is not the only way to examine mortality, which is likely because mass and chemical composition concentrations are generally controlled by larger-sized particles. Our study suggests that the size-specific mortality and/or impacts of size-resolved properties on mortalities need to be evaluated since smaller particles get into the body more efficiently, and therefore, more diverse size-dependent causes and effects can occur. [ABSTRACT FROM AUTHOR]

Background: Increasing evidence regards the role of ambient particles on morbidity and mortality caused by cardiovascular diseases (CVDs). However, there was no evidence about the association between ambient particles and CVD-associated disability. This study used large national representative data to investigate the relationship between long-term exposure to an aerodynamic diameter less than or equal to 2.5 µm (PM2.5) and CVD-associated disability among Chinese adults aged 45 years old and above and estimated the burden of CVD-associated disability attributed to PM2.5. Methods: Using data from the Second National Sample Survey on Disability, this study used a combination of self-reports or family members’ reports and on-site medical diagnosis by experienced specialists to ascertain CVD-associated disability in 852,742 adults aged 45 years old and above. Logistic regression models and spline regression models were used to examine the association between PM2.5 long-term exposure and CVD-associated disability, and the population attributable risk was calculated to assess the burden of CVD-associated disability contributed to PM2.5. Results: Every increase of 10 μg/m3 in PM2.5 was associated with an 8% (OR = 1.08, 95% CI: 1.05, 1.10) increase the odds of CVD-associated disability. Stratified analyses by demographic factors suggested that this association was robust. There were 1.05 (0.74,1.35) million -3.53 (3.29,3.75) million CVD-associated disabilities attributed to high PM2.5 concentration exposure (≥35 µg/m3) among middle-aged and older adults in 2006. A reduction in PM2.5 concentrations to 35 µg/m3 corresponded to a decrease of 13.59% (9.55%, 17.46%)–23.98% (17.17%, 30.25%) in CVD-associated disability by age group, respectively, and this magnitude increased in areas with a high prevalence of CVD-related disability. Conclusions: This study suggests that reducing PM2.5 concentrations may contribute to preventing CVD-associated disability and decreasing air pollution-related medical expenditures and rehabilitation fees.

Background: Increasing evidence regards the role of ambient particles on morbidity and mortality caused by cardiovascular diseases (CVDs). However, there was no evidence about the association between ambient particles and CVD-associated disability. This study used large national representative data to investigate the relationship between long-term exposure to an aerodynamic diameter less than or equal to 2.5 µm (PM2.5) and CVD-associated disability among Chinese adults aged 45 years old and above and estimated the burden of CVD-associated disability attributed to PM2.5. Methods: Using data from the Second National Sample Survey on Disability, this study used a combination of self-reports or family members' reports and on-site medical diagnosis by experienced specialists to ascertain CVD-associated disability in 852,742 adults aged 45 years old and above. Logistic regression models and spline regression models were used to examine the association between PM2.5 long-term exposure and CVD-associated disability, and the population attributable risk was calculated to assess the burden of CVD-associated disability contributed to PM2.5. Results: Every increase of 10 µg/m³ in PM2.5 was associated with an 8% (OR = 1.08, 95% CI: 1.05, 1.10) increase the odds of CVD-associated disability. Stratified analyses by demographic factors suggested that this association was robust. There were 1.05 (0.74,1.35) million -3.53 (3.29,3.75) million CVD-associated disabilities attributed to high PM2.5 concentration exposure (≥35 µg/m³) among middle-aged and older adults in 2006. A reduction in PM2.5 concentrations to 35 µg/m³ corresponded to a decrease of 13.59% (9.55%, 17.46%)-23.98% (17.17%, 30.25%) in CVD-associated disability by age group, respectively, and this magnitude increased in areas with a high prevalence of CVD-related disability. Conclusions: This study suggests that reducing PM2.5 concentrations may contribute to preventing CVD-associated disability and decreasing air pollution-related medical expenditures and rehabilitation fees. [ABSTRACT FROM AUTHOR]

Ambient particles and droplets have a significant effect on climate, visibility, and human health. Once formed, they undergo continuous transformations through condensation and evaporation of water, uptake of low-volatility organic molecules, and photochemical reactions involving various gaseous and condensed-phase species in the atmosphere. These transformations determine the physical and chemical properties of airborne particles, such as their ability to absorb and scatter solar radiation and nucleate cloud droplets. The complexity, heterogeneity, and size of ambient particles make it challenging to understand the kinetics and mechanisms of their formation and chemical transformations. Mass spectrometry (MS) is a powerful analytical technique that enables detailed chemical characterization of both small and large molecules in complex matrices. This capability makes MS a promising tool for studying chemical transformations of particles and droplets in the atmosphere. This review is focused on new and emerging experimental MS-based approaches for understanding the kinetics and mechanisms of such transformations. Some of the techniques discussed herein are best suited for ambient samples, while the others work best in laboratory applications. However, in combination, they provide a comprehensive arsenal of methods for characterization of particles and droplets. In addition, we emphasize the role of fundamental physical chemistry studies in the development of new methods for chemical analysis of ambient particles and droplets.

Many countries have implemented exposure limits for the concentration of ambient particular matter and do therefore have to monitor their concentration. This could be performed with TEOM monitors (Tapered Element Oscillating Microbalance-monitors) that contain a filter on which particles are collected. These filters are regularly exchanged for new ones. The aim of this study was to test the feasibility of collecting used filters from monitors at different locations and establishing a method to extract particles and then study them with respect to their ability to generate oxidants, their endotoxin content, and ability to activate inflammatory cells. Filters from nine geographically spread locations in Sweden were collected during a 21-month period by local technicians who then sent them to the laboratory where they were extracted and analyzed. The procedure to let local technicians perform the filter exchange and send used TEOM filters to the laboratory worked well. A method was established in which pyrogen-free water was used to extract particles that then were aliquoted and stored for later analysis. Particulate matter (PM10) from different locations showed both a considerable seasonal and spatial-dependent difference with respect to oxidative potential (oxidize glutathione), endotoxin content, and ability to activate blood monocytes to release interleukin-1β. This study shows that, instead of discarding TEOM filters, they can be collected and extracted so that particles that have been sampled in a standardized way could be analyzed with respect to variables that reflect their toxicity. This could be done at a low cost. In combination with information about the ambient particle concentration, such information could be helpful in the evaluation of differences in the risk of breathing air at various locations. [ABSTRACT FROM AUTHOR]

Abstract Epidemiological studies have linked outdoor PM 2.5 concentrations to a range of health effects, although people spend most of the time indoors. To better understand how individuals' exposure vary as they move between different indoor and outdoor microenvironments, our study investigated personal PM 2.5 exposure and exposure intensity of 14 adult volunteers over one week (five weekdays and one weekend), using low-cost personal monitors, recording PM 2.5 concentrations in 5 min intervals. Further, the study evaluated community perception of air pollution exposure during the recruitment and engagement with the volunteers. We found that people with tertiary education across all ages had greater interest in participating, with younger people being interested regardless of the level of education. The derived exposures and exposure intensities differed between weekdays and the weekend due to larger variations in individuals' daily routines. In general, time spent at home and engaged in indoor activities was associated with the highest personal PM 2.5 exposure and exposure intensity on both, week and weekend days, implying the significance of both duration of the exposure and the indoor PM 2.5 concentrations. The results showed no relationship between personal exposures and indoor characteristics of home (ventilation, building age and cooktop), which are expected to be due to the study's small sample size. The observed PM 2.5 > 10 μg m−3 were significantly higher for distances <50 m to the roads for both major and minor roads, and were observed in areas with <16% open space, which were also close to a major road. Highlights • Epidemiological studies do not account for indoor PM 2.5 exposures. • Low-cost sensors provide a good indication of microscale PM 2.5 variations. • The highest personal PM 2.5 exposure was at home both on week and weekend days. • PM 2.5 > 10 μg m−3 were significantly higher at distances < 50 m to the roads. • People with tertiary education had more interest in participating across all ages. [ABSTRACT FROM AUTHOR]

A large number of studies have shown much higher health effects of particulate matter (PM) during the warm compared to the cold season. In this paper we present the results of an experimental study carried out in an unoccupied test apartment with the aim of understanding the reasons behind the seasonal variations of the health effects due to ambient PM 2.5 exposure. Measurements included indoor and outdoor PM 2.5 mass and chemical composition as well as particle size distribution of ultrafine particles. Monitoring campaigns were carried out during summer and winter following a ventilation protocol developed to replicate typical occupant behaviour according to a questionnaire-based survey. Our findings showed that seasonal variation of the relationship between ambient and indoor mass concentrations cannot entirely explain the apparent difference in PM toxicity between seasons and size distribution and chemical composition of particles were identified as other possible causes of changes in the apparent PM toxicity. A marked decrease of ultrafine particles (<100 nm) passing from outdoors to indoors was observed during winter; this resulted in higher indoor exposure to nanoparticles (<50 nm) during summer. With regards to the chemical composition, a pooled analysis showed infiltration factors of chemical species similar to that obtained for PM 2.5 mass with values increasing from 0.73 during winter to 0.90 during summer and few deviations from the pooled estimates. In particular, significantly lower infiltration factors and sink effect were found for nitrates and ammonium during winter. In addition, a marked increase in the contribution of indoor and outdoor sulfates to the total mass was observed during summer. [ABSTRACT FROM AUTHOR]

Ambient air pollutant exposure can change the composition of gut microbiota at 6-months of age, but there is no epidemiological evidence on the impacts of exposure to particulate matter with an aerodynamic diameter ≤1 μm (PM 1) during pregnancy on gut microbiota in mothers and neonates. We aimed to determine if gestational PM 1 exposure is associated with the gut microbiota of mothers and neonates. Leveraging a mother-infant cohort from the central region of China, we estimated the exposure concentrations of PM 1 during pregnancy based on residential address records. The gut microbiota of mothers and neonates was analyzed using 16 S rRNA V3–V4 gene sequences. Functional pathway analyses of 16 S rRNA V3–V4 bacterial communities were conducted using Tax4fun. The impact of PM 1 exposure on α-diversity, composition, and function of gut microbiota in mothers and neonates was evaluated using multiple linear regression, controlling for nitrogen dioxide (NO 2) and ozone (O 3). Permutation multivariate analysis of variance (PERMANOVA) was used to analyze the interpretation degree of PM 1 on the sample differences at the OTU level using the Bray-Curtis distance algorithm. Gestational PM 1 exposure was positively associated with the α-diversity of gut microbiota in neonates and explained 14.8% (adj. P = 0.026) of the differences in community composition among neonatal samples. In contrast, gestational PM 1 exposure had no impact on the α- and β-diversity of gut microbiota in mothers. Gestational PM 1 exposure was positively associated with phylum Actinobacteria of gut microbiota in mothers, and genera Clostridium_sensu_stricto_1 , Streptococcus , Faecalibacterium of gut microbiota in neonates. At Kyoto Encyclopedia of Genes and Genomes pathway level 3, the functional analysis results showed that gestational PM 1 exposure significantly down-regulated Nitrogen metabolism in mothers, as well as Two-component system and Pyruvate metabolism in neonates. While Purine metabolism, Aminoacyl-tRNA biosynthesis, Pyrimidine metabolism, and Ribosome in neonates were significantly up-regulated. Our study provides the first evidence that exposure to PM 1 has a significant impact on the gut microbiota of mothers and neonates, especially on the diversity, composition, and function of neonatal meconium microbiota, which may have important significance for maternal health management in the future. • Exposure to PM 1 has significant impacts on the gut microbiota of mothers and neonates. • Gestational PM 1 exposure especially impacts the gut microbiota of neonates. • Interventions from environment perspective may benefit the offspring's gut microbiota. [ABSTRACT FROM AUTHOR]

Exposure to air pollution, especially from particulate matter, is generally accepted to be one of the most important public health problems in Europe and worldwide. The effects caused in the general population are associated with relatively small relative risks, but if the ubiquity of exposure is considered, the attributable number of events is large. Furthermore, there is evidence that the effects in sensitive population subgroups (such as the elderly, those with chronic diseases and children) are stronger. Within large European Union funded collaborative projects (such as the Air Pollution and Health: a European Approach-APHEA), effect modification by geographical characteristics has been investigated and it was found that in warmer countries, in locations where particles come from traffic and where the proportion of the elderly is greater, particle toxicity is increased. These characteristics are particularly relevant to Southern European locations. From other projects we know that meteorological, climatic, environmental and socioeconomic factors are effect modifiers of the effects of specific air pollutants. In this presentation we will show the evidence on the short-term health effects of particulate and gaseous air pollutants and emphasize particularly results concerning southern Europe and potential effect modifiers. The gaps in knowledge and the need to study air pollution in Southern European countries more extensively will be demonstrated. To conduct useful research, good quality air pollution and health data are needed.

Ambient ultrafine particle number concentrations (PNC) have inhomogeneous spatio-temporal distributions and depend on a number of different urban factors, including background conditions and distant sources. This paper quantitatively compares exposure to ambient ultrafine particles at urban schools in two cities in developed countries, with high insolation climatic conditions, namely Brisbane (Australia) and Barcelona (Spain). The analysis used comprehensive indoor and outdoor air quality measurements at 25 schools in Brisbane and 39 schools in Barcelona. PNC modes were analysed with respect to ambient temperature, land use and urban characteristics, combined with the measured elemental carbon concentrations, NO x (Brisbane) and NO 2 (Barcelona). The trends and modes of the quantified weekday average daily cycles of ambient PNC exhibited significant differences between the two cities. PNC increases were observed during traffic rush hours in both cases. However, the mid-day peak was dominant in Brisbane schools and had the highest contribution to total PNC for both indoors and outdoors. In Barcelona, the contribution from traffic was highest for ambient PNC, while the mid-day peak had a slightly higher contribution for indoor concentrations. Analysis of the relationships between PNC and land use characteristics in Barcelona schools showed a moderate correlation with the percentage of road network area and an anti-correlation with the percentage of green area. No statistically significant correlations were found for Brisbane. Overall, despite many similarities between the two cities, school-based exposure patterns were different. The main source of ambient PNC at schools was shown to be traffic in Barcelona and mid-day new particle formation in Brisbane. The mid-day PNC peak in Brisbane could have been driven by the combined effect of background and meteorological conditions, as well as other local/distant sources. The results have implications for urban development, especially in terms of air quality mitigation and management at schools. [ABSTRACT FROM AUTHOR]

Background: Recent epidemiological studies indicate negative associations between a diverse group of air pollutants and cognitive functioning in children and adults, and aspects of attention deficit in children. Neuroinflammation and oxidative stress are two putative biological mechanisms by which air pollutants may adversely affect the brain. Objectives: We sought to determine whether exposure to concentrated ambient particulate matter (CAPS) during the first 2 weeks of life, alone or again in adulthood, could alter responding for delayed reward, a critical component of human decision making. Greater preference for immediate reward has been implicated as a component of several psychiatric disorders, addiction, obesity, and attention deficit. Methods: C57BL/6J mice were exposed to ultrafine particles (< 100 nm in aerodynamic diameter; CAPS) using the Harvard University Concentrated Ambient Particle System (HUCAPS) or filtered air in the postnatal period (days 4-7 and 10-13) with and without adult exposure over days 56-60. In adulthood, delay behavior was assessed using a fixed-ratio waiting-for-reward (FR wait) paradigm in which 25 responses (FR25) were required to initiate the waiting-for-reward component during which mice obtained "free" sucrose pellets with the stipulation that these "free" pellets were delivered at increasing delay intervals. Results: Coupled with increased FR response rates, mice exposed to postnatal CAPS displayed increased FR resets that reinstated short delays, indicating a preference for shorter delays, despite the added response cost of the FR25. No associated changes in locomotor activity were observed. Conclusions: Postnatal CAPS exposure produces an enhanced bias towards immediate rewards, a risk factor for several central nervous system (CNS) disorders. This enhancement does not appear to be the result of hyperactivity. The findings underscore the need for further evaluation of air pollution effects on the CNS and its potential contribution to CNS diseases and disorders.. [ABSTRACT FROM AUTHOR]

Background: Increasing evidence regards the role of ambient particles on morbidity and mortality caused by cardiovascular diseases (CVDs). However, there was no evidence about the association between ambient particles and CVD-associated disability. This study used large national representative data to investigate the relationship between long-term exposure to an aerodynamic diameter less than or equal to 2.5 µm (PM 2.5 ) and CVD-associated disability among Chinese adults aged 45 years old and above and estimated the burden of CVD-associated disability attributed to PM 2.5 ., Methods: Using data from the Second National Sample Survey on Disability, this study used a combination of self-reports or family members' reports and on-site medical diagnosis by experienced specialists to ascertain CVD-associated disability in 852,742 adults aged 45 years old and above. Logistic regression models and spline regression models were used to examine the association between PM 2.5 long-term exposure and CVD-associated disability, and the population attributable risk was calculated to assess the burden of CVD-associated disability contributed to PM 2.5 ., Results: Every increase of 10 μg/m 3 in PM 2.5 was associated with an 8% (OR = 1.08, 95% CI: 1.05, 1.10) increase the odds of CVD-associated disability. Stratified analyses by demographic factors suggested that this association was robust. There were 1.05 (0.74,1.35) million -3.53 (3.29,3.75) million CVD-associated disabilities attributed to high PM 2.5 concentration exposure (≥35 µg/m 3 ) among middle-aged and older adults in 2006. A reduction in PM 2.5 concentrations to 35 µg/m 3 corresponded to a decrease of 13.59% (9.55%, 17.46%)-23.98% (17.17%, 30.25%) in CVD-associated disability by age group, respectively, and this magnitude increased in areas with a high prevalence of CVD-related disability., Conclusions: This study suggests that reducing PM 2.5 concentrations may contribute to preventing CVD-associated disability and decreasing air pollution-related medical expenditures and rehabilitation fees., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright: © 2022 The Author(s).)

Abstract: Molecular weight (mw) 247 nitrofluoranthenes and nitropyrenes and mw 273 nitrotriphenylenes (NTPs), nitrobenz[a]anthracenes, and nitrochrysenes were quantified in ambient particles collected in Riverside, CA, Tokyo, Japan, and Mexico City, Mexico. 2-Nitrofluoranthene (2-NFL) was the most abundant nitro-polycyclic aromatic hydrocarbon (nitro-PAH) in Riverside and Mexico City, and the mw 273 nitro-PAHs were observed in lower concentrations. However, in Tokyo concentrations of 1-+2-NTP were more similar to that of 2-NFL. NIST SRM 1975 diesel extract standard reference material was also analyzed to examine nitro-PAH isomer distributions, and 12-nitrobenz[a]anthracene was identified for the first time. The atmospheric formation pathways of nitro-PAHs were studied from chamber reactions of fluoranthene, pyrene, triphenylene, benz[a]anthracene, and chrysene with OH and NO3 radicals at room temperature and atmospheric pressure, with the PAH concentrations being controlled by their vapor pressures. Sampling media were spiked with deuterated PAH to examine heterogeneous nitration. Comparing specific nitro-PAH ratios in ambient and diesel particles with those from our chamber experiments suggests that the low 2-NFL/NTPs ratios in Tokyo particulate matter are not a result of gas-phase radical-initiated chemistry since both gas-phase OH and NO3 radical-initiated reactions result in high 2-NFL/NTPs ratios. Comparisons of the relative formation of deuterated nitro-PAHs on the sampling media suggest that heterogeneous reactions with N2O5 on ambient particle surfaces also do not explain the nitro-PAH profiles of Tokyo particles. Thus, the source of NTPs in Tokyo remains unidentified. [Copyright &y& Elsevier]

The present work presents a measurement uncertainty evaluation according to Guide to the Expression of Uncertainty in Measurement (GUM) of the concentration of the cations K and Li and anions NO and SO in fine airborne particulate matter, refers to particles less than 2.5 μm in diameter (PM), as measured by ion chromatography (US-EPA 300 method). The GUM method is not typically used to report uncertainty. In general, the analytical results only report the measurement's standard deviation under repetition as an uncertainty; thus, not all sources of uncertainty are considered. In this work, the major sources of uncertainty regarding the measurements were identified as contributions to linear least square regression lines, repeatability, precision, and trueness. The expanded uncertainty was approximately 20% for anions and cations. The largest contribution to uncertainty was found to be repeatability. [ABSTRACT FROM AUTHOR]

Epidemiological studies have reported associations of ambient particulate air pollution, especially particulate matter (PM) less than 10 μm with exacerbations of asthma and chronic obstructive pulmonary disease. In an in vivo model, we have tested the toxicity of urban airborne particles collected during spring, summer, and winter seasons in four cities (Amsterdam, Lodz, Oslo, and Rome) spread across Europe. The seasonal differences in inflammatory responses were striking, and almost all the study parameters were affected by PM. Coarse fractions of the urban particle samples were less potent per unit mass than the fine fractions in increasing cytokine [macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)-α] levels and in reducing Clara-cell secretory protein (CC16) levels. This study shows that PM collected at 4 contrasting sites across Europe and during different seasons have differences in toxic potency. These differences were even more prominent between the fine and coarse fractions of the PM. [ABSTRACT FROM PUBLISHER]

Our approach to study multi-pollutant aerosols isolates a single emissions source, evaluates the toxicity of primary and secondary particles derived from this source, and simulates chemical reactions that occur in the atmosphere after emission. Three U.S. coal-fired power plants utilizing different coals and with different emission controls were evaluated. Secondary organic aerosol (SOA) derived from α-pinene and/or ammonia was added in some experiments. Male Sprague-Dawley rats were exposed for 6 h to filtered air or different atmospheric mixtures. Scenarios studied at each plant included the following: primary particles (P); secondary (oxidized) particles (PO); oxidized particles ++ SOA (POS); and oxidized and neutralized particles ++ SOA (PONS); additional control scenarios were also studied. Continuous respiratory data were obtained during exposures using whole body plethysmography chambers. Of the 12 respiratory outcomes assessed, each had statistically significant changes at some plant and with some of the 4 scenarios. The most robust outcomes were found with exposure to the PO scenario (increased respiratory frequency with decreases in inspiratory and expiratory time); and the PONS scenario (decreased peak expiratory flow and expiratory flow at 50%). PONS findings were most strongly associated with ammonium, neutralized sulfate, and elemental carbon (EC) in univariate analyses, but only with EC in multivariate analyses. Control scenario O (oxidized without primary particles) had similar changes to PO. Adjusted R2 analyses showed that scenario was a better predictor of respiratory responses than individual components, suggesting that the complex atmospheric mixture was responsible for respiratory effects. [ABSTRACT FROM AUTHOR]

The toxicological evaluation of realistic emissions of source aerosols (TERESA) study seeks to delineate health effects of aerosols formed from emissions of particulate matter sources. This series of papers reports the findings of experiments using coal-fired power plants as the source of emissions and this paper summarizes the findings and knowledge acquired from these studies. Emissions were drawn directly from the stacks of three coal-fired power plants in the US, and photochemically aged in a mobile laboratory to simulate downwind power plant plume processing. The power plants used different sources of coal and had different emission controls. Exposure scenarios included primary particles, secondary particles and mixtures of these with common atmospheric constituents (α-pinene and ammonia). Extensive exposure characterization was carried out, and toxicological outcomes were evaluated in Sprague-Dawley rats exposed to different emission scenarios. Breathing pattern, pulmonary inflammatory responses, in vivo pulmonary and cardiac chemiluminescence and cardiac response in a model of acute myocardial infarction were assessed. The results showed no response or relatively mild responses to the inhaled aerosols studied; complex scenarios which included oxidized emissions and α-pinene to simulate biogenic secondary organic aerosol tended to induce more statistically significant responses than scenarios of oxidized and non-oxidized emissions alone. Relating adverse effects to specific components did not consistently identify a toxic constituent. These findings are consistent with most of the previously published studies using pure compounds to model secondary power plant emissions, but importantly add substantial complexity and thus have considerable merit in defining toxicological responses. [ABSTRACT FROM AUTHOR]

In vivo chemiluminescence (CL) is a measure of reactive oxygen species in tissues. CL was used to assess pulmonary and cardiac responses to inhaled aerosols derived from aged emissions of three coal-fired power plants in the USA. Sprague-Dawley rats were exposed to either filtered air or: (1) primary emissions (P); (2) ozone oxidized emissions (PO); (3) oxidized emissions ++ secondary organic aerosol (SOA) (POS); (4) neutralized oxidized emissions ++ SOA (PONS); and (5) control scenarios: oxidized emissions ++ SOA in the absence of primary particles (OS), oxidized emissions alone (O), and SOA alone (S). Immediately after 6 hours of exposure, CL in the lung and heart was measured. Tissues were also assayed for thiobarbituric acid reactive substances (TBARS). Exposure to P or PO aerosols led to no changes compared to filtered air in lung or heart CL at any individual plant or when all data were combined. POS caused significant increases in lung CL and TBARS at only one plant, and not in combined data from all plants; PONS resulted in increased lung CL only when data from all plants were combined. Heart CL was also significantly increased with exposure to POS only when data from all plants were combined. PONS increased heart CL significantly in one plant with TBARS accumulation, but not in combined data. Exposure to O, OS, and S had no CL effects. Univariate analyses of individual measured components of the exposure atmospheres did not identify any component associated with increased CL. These data suggest that coal-fired power plant emissions combined with other atmospheric constituents produce limited pulmonary and cardiac oxidative stress. [ABSTRACT FROM AUTHOR]

Five-stage size-segregated ambient aerosol particles were collected during January 2003 until October 2004 at one urban and one suburban site of Beijing to investigate the seasonal size distributions of aliphatic and polycyclic aromatic hydrocarbons. The concentrations of total n-alkanes ranging from C11 to C35 varied between 2.1 and 2446 ngm3, with higher values at the urban site than suburban site. A seasonal fluctuation was clearly evident, with higher concentrations occurring during the colder period. The carbon preference index (CPI) of the n-alkanes displayed the highest values in the spring and apparently decreased in winter. Furthermore, smaller size airborne particle-bound n-alkanes tend to have lower CPI values. In addition, the presence of pristane, phytane, n-alkylcyclohexanes, hopanes, and steranes, together with the major unresolved complex mixture (UCM) of branched and cyclic compounds, confirmed the contribution from fossil fuel use in ambient aerosol particles of Beijing. The concentrations of 18 unsubstituted PAHs (18-PAH) varied from 0.84883 ngm3, with the content at the urban site 1.16.6 times higher than those for the suburban site. The seasonal variation of 18-PAH concentrations was as follows winter > autumn > spring > summer. About 6788 of the PAHs were associated with particles having an aerodynamic diameter 2.0 m. PAHs concentration diagnostic ratios reflect that the major source of fine particles is from fossil fuel utilization. [ABSTRACT FROM AUTHOR]

Abstract: Although ambient air was first shown to be carcinogenic in 1947 and mutagenic in 1975, no overarching review of the subsequent literature has been produced. Recently, Claxton et al. [L.D. Claxton, P.P. Matthews, S.H. Warren, The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicity, Mutat. Res./Rev. Mutat. Res. 567 (2004) 347–399] reviewed the literature on the mutagenicity of urban air in the Salmonella mutagenicity assay. Here, we review the literature on the mutagenicity of urban air in other test systems and review the carcinogenicity of urban air in experimental systems. Urban air was carcinogenic in most of the reports involving rodents. Studies ascribed carcinogenic activity primarily to PAHs, nitroarenes, and other aromatic compounds. Atmospheric conditions, along with the levels and types of pollutants, contributed to the variations in carcinogenic and mutagenic activity of air from different metropolitan areas. The majority of the mutagenesis literature was in the Salmonella assay (50%), with plant systems accounting for most of the rest (31%). The present data give little support to the use of plant systems to compare air mutagenicity among multiple sites or studies. Studies in mice have shown that particulate air pollution causes germ-cell mutations. Air sheds contain similar types and classes of mutagens; however, the levels of these compounds vary considerably among air sheds. Combustion emissions were associated with much of the mutagenicity and carcinogenicity of urban air. Most studies focused on the particulate fraction; thus, additional work is needed on the volatile and semi-volatile fractions, metals, and atmospheric transformation. Smaller particles have greater percentages of extractable organic material and are more mutagenic than larger particles. Although hundreds of genotoxic compounds have been identified in ambient air, only a few (<25) are routinely monitored, emphasizing the value of coupling bioassay with chemistry in the monitoring of air for carcinogenic and mutagenic activities and compounds. [Copyright &y& Elsevier]

BACKGROUND: Particulate matter (PM) has been reported to be associated with alterations in heart rate variability (HRV); however, the results are inconsistent. We propose that different components of PM cause the discrepancy. OBJECTIVE: In this study, our goal was to determine whether different types of exposure would cause different HRV effects, and to verify the interactions between co-exposing components. METHODS: Ultrafine carbon black (ufCB; 14 nm; 415 µg and 830 µg), ferric sulfate [Fe2(SO4)3; 105 µg and 210 µg], nickel sulfate (NiSO4; 263 µg and 526 µg), and a combination of high-dose ufCB and low-dose Fe2(SO4)3 or NiSO4 were intratracheally instilled into spontaneously hypertensive rats. Radiotelemetry data were collected in rats for 72 hr at baseline and for 72 hr the following week to determine the response to exposure. Effects of exposure on 5-min average of normal-to-normal intervals (ANN), natural logarithm-transformed standard deviation of the normal-to- normal intervals (LnSDNN), and root mean square of successive differences of adjacent normal-to- normal intervals (LnRMSSD) were analyzed using self-control experimental designs. RESULTS: Both high- and low-dose ufCB decreased ANN marginally around hour 30, with concurrent increases of LnSDNN. LnRMSSD returned to baseline levels after small initial increases. We observed minor effects after low-dose Fe and Ni instillation, whereas biphasic changes were noted after high-dose instillations. Combined exposures of ufCB and either Fe or Ni resulted in HRV trends different from values estimated from individual-component effects. CONCLUSIONS: Components in PM may induce different cardioregulatory responses, and a single component may induce different responses during different phases. Concurrent exposure to ufCB and Fe or Ni might introduce interactions on cardioregulatory effects. Also, the effect of PM may be mediated through complex interaction between different components of PM. [ABSTRACT FROM AUTHOR]

Abstract: In 2003, a bus strike paralyzed the fleet of buses in São Paulo, Brazil during 3 days, from 6 to 8 of April, the complete interruption of services being achieved on the 7th. We evaluated the effect of the absence of this source of pollution on the composition, mutagenicity, and toxicity of the fine particulate material collected during this period. Particles were sampled in glass fiber filters on days 7 and 15 of April of 2003 (strike and nonstrike days, respectively), using a high-volume sampler. Trace element determinations (As, Br, Co, Cl, Fe, La, Mn, Sb, Sc, and Th) of particulate material samples were carried out by neutron activation analysis. Sulfur determination was done by X-ray fluorescence analysis. The ratio between nonstrike/strike concentrations of hydrocarbons associated with automotive emissions (benzene, toluene, ethyl-benzene, and xylenes; BTEX) was determined by gas chromatography/mass spectrometry. Mutagenesis of testing solutions was determined by means of the Tradescantia micronucleus assay in early tetrads of Tradescantia pallida. The inhibition of mitosis of the cells of the primary meristema of the root tips of Allium cepa was used as an index of the toxicity. Fine particle trace element contents were lower during the strike. The concentrations of sulfur and BTEX were 50% and 39.3% lower, respectively, on the strike day. A significant () reduction of micronuclei induced by fine particles sampled during the strike was observed. No effect of the strike on toxicity was detected. These results indicate that a program aiming to reduce emissions of the bus fleet in our town may impact positively the air quality by reducing the mutagenic potential of ambient particles. [Copyright &y& Elsevier]

PM10 and PM2.5 fractions were collected by high-volume cascade impactors during 4-week periods in spring, summer and winter seasons in Amsterdam, Lodz, Oslo and Rome and at a Dutch seaside site. The samples were screened for respiratory allergy potential with the mouse popliteal lymph node (PLN) and the ELISA-based IgE antibody assays. For inflammatory screening, release of the cytokine macrophage inflammatory protein-2 (MIP-2) from primary rat type 2 cells was determined. Most fractions gave an increase in the lymph node response with the model allergen ovalbumin indicating adjuvant activity. Some of the coarse fractions gave a lymph node response even in the absence of ovalbumin, caused probably by non-specific inflammation. With the exception of a few of the coarse fractions, all ambient fractions increased the production of specific IgE. Fine particles had stronger adjuvant effect than coarse particles. A significant increase in the allergen specific IgG2a response was observed for the fine and some of the coarse fractions, indicating a non-allergic Th1 response. No consistent differences in adjuvant effects between the locations were observed. Particle samples collected in the different European cities differed in their potency to induce MIP-2 in type 2 cells. Coarse fractions of the urban particles samples, as well as the coarse fraction collected at the seaside, were more potent than the fine fractions to induce MIP-2. With respect to seasonal variations, the coarse fractions collected in summer seemed to be the most potent. [Copyright &y& Elsevier]

The health impact of dust events from China has become a concern within China and in its neighboring countries. Previous epidemiological studies have demonstrated an association between particulate matter exposure and cardiopulmonary mortality. Here, we use pulmonary hypertensive rat models to examine inflammation markers in the lung and in peripheral blood after exposure to Asian dust storm particles. Using a nose-only inhalation system, eight pulmonary hypertensive rats were exposed to concentrated ambient particles (CAPs) from an actual Asian dust storm that took place between March 18 and 19, 2002; four control rats were also exposed to room air. Four rats exposed to CAPs of 315.6 μg/m3 for 6 h were classified as the low-exposure group, and another four rats exposed to CAPs of 684.5 μg/m3 for 4.5 h were classified as the high-exposure group. The animals were sacrificed 36 h after exposure. Inflammation markers in the peripheral blood and in the bronchoalveolar lavage (BAL) were analyzed, and IL-6 in BAL was also determined using ELISA. White blood cell counts in peripheral blood increased with increased CAP exposure levels (P<0.001, test for trend). In BAL analysis, total cell numbers and the proportion of neutrophil also increased with increased CAP levels (P<0.001, test for trend for both markers). Positive dose–response relationships between CAP exposure and total protein (P<0.05) and between CAPs and LDH activity (P<0.05) were also observed. Moreover, IL-6 protein in BAL increasing with CAP levels (P<0.05, test for trend) was demonstrated. Our results revealed that exposure to particulate matters during an Asian dust storm could increase lung inflammation and injury in pulmonary hypertensive rats. Further studies are needed to determine the components of dust storm particles that may contribute to the particle toxicity. [Copyright &y& Elsevier]

The toxic effects of air pollution are widely documented. In recent years, however, there has been an increasing interest in the study of the health effects of particulate matter (PM), a previously unexplored constituent of urban air pollution. Exposure to increased levels of PM of respirable size is strongly and consistently associated with increased cardiopulmonary morbidity and mortality. Conversely, improved air quality appears to correlate with decreased mortality. Particulate matter is a mixture of inorganic and organic components that vary in size, origin, and composition. The mechanisms of PM health effects are still poorly understood. However, studies in cellular and animal models suggest a variety of possible mechanisms including direct effects of particle components on the intracellular sources of reactive oxygen species (ROS), indirect effects due to pro-inflammatory mediators released from PM-stimulated macrophages, and neural stimulation after particle deposition in the lungs. The involvement of ROS in each one of these possible pathways is discussed. [Copyright &y& Elsevier]

Acellular assays of oxidative potential (OP) induced by ambient particulate matters (PMs) are of great significance in screening for toxicity in PMs. In this review, several typical OP measurement techniques, including the respiratory tract lining fluid assay (RTLF), ascorbate depletion assay (AA), dithiothreitol assay (DTT), chemiluminescent reductive acridinium triggering (CRAT), dichlorofluorescin assay (DCFH) and electron paramagnetic/spin resonance assay (EPR/ESR) are discussed and their sensitivity to different PMs species composition, PMs size distribution and seasonality is compared. By comparison, the DTT assay tends to be the preferred method providing a more comprehensive measurement with transition metals and quinones accumulated in the fine PMs fraction. Specific transition metals (i.e., Mn, Cu, Fe) and quinones are found to contribute OPDTT directly whereas the redox properties of PMs species may be changed by the interactions between themselves. The selection of the appropriate OP measurement methods and the accurate analysis of the relationship between the methods and PM components is conducive to epidemiological researches which are related with oxidative stress induced by PMs exposure. [ABSTRACT FROM AUTHOR]

Experimental studies have indicated that alterations in the gut microbiota might play a role in the pathway of diabetes induction resulting from particulate matter pollution with aerodynamic diameters < 2.5 μm (PM 2.5). However, few human studies have examined such experimental findings. Here, we examine the mediating effects of gut microbial dysbiosis on the associations between PM 2.5 and particulate matter pollution with aerodynamic diameters < 1 μm (PM 1) on diabetes using the Guangdong Gut Microbiome Project (GGMP) dataset. A multistage cluster sampling method was employed to recruit adult participants from communities in Guangdong. Each participant was interviewed using a questionnaire, fasting blood and stool samples were collected, and the exposure to air pollutants was assessed using a spatiotemporal land-use regression model. The mediation analysis was conducted to estimate the associations among air pollutants, gut microbiota diversity and diabetes. Both PM 2.5 and PM 1 were positively associated with the risks of impaired fasting glucose (IFG) or type 2 diabetes and negatively associated with alpha diversity indices of the gut microbiota. The mediation analyses indicated that the associations of PM 2.5 and PM 1 with the risk of type 2 diabetes were partially mediated by the decrease in gut microbiota diversity. Moreover, we found that 79 (PM 2.5 on IFG), 84 (PM 2.5 on type 2 diabetes), 83 (PM 1 on IFG) and 89 (PM 1 on type 2 diabetes) bacterial taxa could partially mediate the associations of PM 2.5 and PM 1 with IFG and type 2 diabetes, respectively. The relative abundance of most Firmicutes , Proteobacteria and Verrucomicrobia bacteria were negatively associated with particulate matter (PM) concentrations and the risks of diabetes. Long-term exposure to PM may increase the risk of diabetes, and alterations in the gut microbiota partially explained these associations. Unlabelled Image • Long-term exposure to PM may increase the risks of IFG and T2DM, and decrease the diversity of gut microbiota. • The alternations of gut microbiota diversity could partially mediate the associations of PM with diabetes risk. • Bacterial taxa could partially mediate the effects of PM 2·5 and PM 1 on IFG and T2DM. [ABSTRACT FROM AUTHOR]