Effects of PM10 Airborne Particles from Different Regions of a Megacity on In Vitro Secretion of Cytokines by a Monocyte Line during Different Seasons.

Several epidemiological studies have demonstrated that particulate matter (PM) in air pollution can be involved in the genesis or aggravation of different cardiovascular, respiratory, perinatal, and cancer diseases. This study assessed the in vitro effects of PM10 on the secretion of cytokines by a human monocytic cell line (THP-1). We compared the chemotactic, pro-inflammatory, and anti-inflammatory cytokines induced by PM10 collected for two years during three different seasons in five different Mexico City locations. MIP-1α, IP-10, MCP-1, TNF-α, and VEGF were the main secretion products after stimulation with 80 µg/mL of PM10 for 24 h. The THP-1 cells showed a differential response to PM10 obtained in the different sites of Mexico City. The PM10 from the north and the central city areas induced a higher pro-inflammatory cytokine response than those from the south. Seasonal pro-inflammatory cytokine secretion always exceeded anti-inflammatory secretion. The rainy-season-derived particles caused the lowest pro-inflammatory effects. We concluded that toxicological assessment of airborne particles provides evidence supporting their potential role in the chronic exacerbation of local or systemic inflammatory responses that may worsen the evolution of some chronic diseases.

Autistic Regression and Exposure to Industrial Chemicals: Preliminary Observations.

Exposure to industrial pollutants is a potential risk factor not fully explored in ASD with regression (ASD+R). We studied geographical collocation patterns of industrial air chemical emissions and the location of homes of children with ASD+R at different exposure times, compared with ASD cases without regression (ASD-R). Fifteen of 111 emitted chemicals collocated with ASD+R, and 65 with ASD-R. ASD+R collocated more strongly with different neurotoxicants/immunotoxicants a year before diagnosis, whereas ASD-R were moderately collocated with chemicals across all exposure periods. This preliminary exploratory analysis of differences in exposure patterns raises a question regarding potential pathophysiological differences between the conditions.

Climate change impacts on the health of South Asian children and women subpopulations - A scoping review.

Background and objectives: Climate change impacts are felt unequally worldwide; populations that experience geographical vulnerability, those living in small island states and densely populated coastal areas, and children and women are affected disproportionately. This scoping review aims to synthesize evidence from relevant studies centred on South Asia, identify research gaps specifically focused on children and women's health, and contribute to knowledge about South Asia's existing mitigation and adaptation strategies. Methods: A research librarian executed the search on six databases using controlled vocabulary (e.g., MeSH, Emtree, etc.) and keywords representing the concepts "vulnerable populations" and "climate change" and "health impacts" and "South Asia." Databases were searched from January 2010 to May 2020. Papers were screened independently by two researchers. Results: Forty-two studies were included, of which 23 were based in India, 14 in Bangladesh, and five in other South Asian countries. Nineteen studies focused on meteorological factors as the primary exposure. In contrast, thirteen focused on extreme weather events, nine on air pollution, and one on salinity in coastal areas. Thirty-four studies focused on the health impacts on children related to extreme weather events, meteorological factors, and air pollution, while only eight studies looked at health impacts on women. Undernutrition, ARI (acute respiratory infection), diarrheal diseases, low birth weight, and premature mortality were the major health impacts attributed to extreme weather events, meteorological factors, and air pollution exposure in children and women in the region. Conclusion: Extreme weather events, meteorological factors and air pollution have affected the health of children and women in South Asia. However, the gap in the literature across the South Asian countries concerning relationships between exposure to extreme weather events, meteorological factors, air pollution and health effects, including mental health problems in children and women, are opportunities for future work.

Ambient Air Pollution and Pediatric Inflammatory Bowel Diseases: An Updated Scoping Review.

To review and discuss recent findings on the associations between pediatric/early-life exposures to ambient air pollution and the risk of pediatric-onset inflammatory bowel diseases (IBD). A scoping review was conducted using the Peters Micah et al. framework. We searched, selected, extracted, and reviewed information from published peer-reviewed papers from three bibliographic databases, chosen to cover a broad range of disciplines. Limits on date (last decade), language, and subject were placed on the database search. The search identified 109 papers from 2010 to June 2021. After screening, we identified nine articles with data on air pollution as a risk factor for IBD, but only four epidemiologic studies directly investigated the association between air pollution and IBD development in children and young adults. These four papers show that air pollution components have different associations with pediatric IBD (pIBD) incidence. Consequently, sulfur dioxide (SO2), nitrogen dioxide (NO2), and the oxidant capacity of air pollution (Ox) were positively associated with pIBD incidence, whereas the association effects of particulate matter (PM) and ozone (O3) exposures were not clear. Despite good scientific rationale and some studies, the evidence on the role that air pollution has in IBD development is limited, highlighting the need for further investigation. Future studies should include the epidemiology of air pollutants and its sources, identifying and understanding mechanisms linking air pollution and pIBD, and identifying signatures of biological responses to air pollutants.

Residential proximity to greenness and adverse birth outcomes in urban areas: Findings from a national Canadian population-based study.

BACKGROUND: Over the last decade, several studies have reported that residential proximity to vegetation, or 'greenness', is associated with improved birth outcomes, including for term birth weight (TBW), preterm birth (PTB), and small for gestational age (SGA). However, there remain several uncertainties about these possible benefits including the role of air pollution, and the extent to they are influenced socioeconomic status. METHODS: We addressed these gaps using a national population-based study of 2.2 million singleton live births in Canadian metropolitan areas between 1999 and 2008. Exposures to greenness, fine particulate matter (PM2.5), and nitrogen dioxide (NO2) were assigned to infants using the postal code of their mother's residence at the time of birth. The Normalized Difference Vegetation Index (NDVI) was used to characterize greenness, while estimates of ambient PM2.5 and NO2 were estimated using remote sensing, and a national land-use regression surface, respectively. Multivariable regression analysis was performed to describe associations between residential greenness and the birth outcomes. Stratified analyses explored whether these associations were modified by neighbourhood measures of socioeconomic status. RESULTS: Mothers who lived in greener areas had a lower risk of low TBW, PTB, and SGA babies. These associations persisted after adjustment for ambient NO2 and PM2.5. Specifically, in fully adjusted models, an interquartile range (IQR = 0.16) increase in the NDVI within a residential buffer of 250 m yielded odds ratios of 0.93 (95% confidence interval (CI): 0.92, 0.94), 0.94 (95% CI: 0.92, 0.95), and 0.94 (95% CI: 0.93, 0.95) for the outcomes of PTB, low TBW, and SGA, respectively. Similarly, an IQR increase in greenness was associated with a 16.3 g (95% CI: 15.3, 17.4) increase in TBW. We found inverse associations between greenness and the occurrence of adverse birth outcomes regardless of the socioeconomic status of the neighbourhood. INTERPRETATION: Our findings support the hypothesis that residential greenness contributes to healthier pregnancies, that these associations are independent from exposure to air pollution. , and that proximity to greenness benefits all mothers regardless of socioeconomic status.

Effect of titanium dioxide nanoparticles on DNA methylation of human peripheral blood mononuclear cells.

The aim of the current study was to investigate the effect of well-characterized TiO2 nanoparticles on DNA methylation of peripheral blood mononuclear cells (PBMCs) in vitro. Maximum non-toxic concentration of nanoparticles for PBMCs was determined by MTT assay. The effect of TiO2 nanoparticles at concentrations of 25-100 µg/ml on DNA methylation of PBMCs was investigated by measuring the %5-mC alterations through an ELISA assay. The physicochemical analysis showed that the TiO2 nanoparticles were crystalline, pure and in the anatase phase. Peaks related to Ti-O tensile vibrations were observed in the range of 1510 cm-1. The size of nanoparticles was in the range of 39-74 nm with an average hydrodynamic diameter of 43.82 nm. According to the results of the MTT test, 100 µg/ml was found to be maximum non-toxic concentration. The %5-mC in treated PBMCs revealed that TiO2 nanoparticles could lead to DNA hypomethylation in PBMCs. The %5-mC difference compared with the negative control was found to be 2.07 ± 1.02% (P = 0.03). The difference of %5-mC between the 25 and 100 µg/ml concentration of nanoparticles was statistically significant (P = 0.02). The results of the current study show that the TiO2 nanoparticles cause DNA hypomethylation in PBMCs in a dose-response manner. Therefore, it is recommended to evaluate the effects of cytotoxicity and epigenotoxicity of commonly used nanoparticles before their use.

Childhood Leukemia in Small Geographical Areas and Proximity to Industrial Sources of Air Pollutants in Three Colombian Cities.

Acute leukemia is the most common childhood cancer and has been associated with exposure to environmental carcinogens. This study aimed to identify clusters of acute childhood leukemia (ACL) cases and analyze their relationship with proximity to industrial sources of air pollution in three capital cities in Colombia during 2000-2015. Incident ACL cases were obtained from the population cancer registries for the cities of Bucaramanga, Cali, and Medellín. The inventory of industrial sources of emissions to the air was obtained from the regional environmental authorities and industrial conglomerates were identified. The Kulldorf's circular scan test was used to detect city clusters and to identify clusters around industrial conglomerates. Multivariable spatial modeling assessed the effect of distance and direction from the industrial conglomerates controlling for socioeconomic status. We identified industrials sectors within a buffer of 1 km around industrial conglomerates related to the ACL clusters. Incidence rates showed geographical heterogeneity with low spatial autocorrelation within cities. The spatio-temporal tests identified one cluster in each city. The industries located within 1 km around the ACL clusters identified in the three cities represent different sectors. Exposure to air pollution from industrial sources might be contributing to the incidence of ACL cases in urban settings in Colombia.

Natural environments in the urban context and gut microbiota in infants.

The biodiversity hypothesis that contact with natural environments (e.g. native vegetation) and biodiversity, through the influence of environmental microbes, may be beneficial for human commensal microbiota has been insufficiently tested. We aimed to study the association between living near natural environments in the urban context, and gut microbiota diversity and composition in young infants. Based on data linkage between the unique Urban Primary Land and Vegetation Inventory (uPLVI) for the city of Edmonton and 355 infants in the CHILD Cohort Study, infant exposure to natural environments (any and specific types, yes/no) was determined within 500 m and 1000 m of their home residence. Gut microbiota composition and diversity at age 4 months was assessed in infant fecal samples. Adjusted for covariates, we observed a reduced odds of high microbial alpha-diversity in the gut of infants exposed to any natural environment within 500 m [Shannon index aOR (95%CI) = 0.63 (0.40, 0.98) and Simpson index = 0.63 (0.41, 0.98)]. In stratified analyses, these associations remained only among infants not breastfed or living with household pets. When doubly stratifying by these variables, the reduced likelihood of high alpha-diversity was present only among infants who were not breastfed and lived with household pets [9% of the study population, Shannon index = 0.07 (0.01, 0.49) and Simpson index = 0.11 (0.02, 0.66)]. Differences in beta-diversity was also seen (p = 0.04) with proximity to a nature space in not breastfed and pets-exposed infants. No associations were observed among infants who were fully formula-fed but without pets at home. When families and their pets had close access to a natural environment, Verrucomicrobiales colonization was reduced in the gut microbiota of formula-fed infants, the abundance of Clostridiales was depleted, whereas the abundance of Enterobacteriales was enriched. Our double-stratified results indicate that proximity to a natural environment plus pet ownership has the capacity to alter the gut microbiota of formula-fed infants. Further research is needed to replicate and better interpret these results, as well as to understand their health consequences.

Air pollution and children's respiratory health: a scoping review of socioeconomic status as an effect modifier.

OBJECTIVES: Air pollution is a leading environmental risk, and socioeconomic status (SES) is postulated as an effect modifier, especially in children. There is a growing interest in exploring this modifier. The present manuscript reviews SES as an effect modifier in children's respiratory health. METHODS: A search in the PubMed and SCOPUS databases was conducted in September 2017 to identify studies with the inclusion criteria of being centred on children, respiratory outcomes, air pollutants and SES measurement. RESULTS: A total of 17 studies were included. Twelve used single SES variables, and the remaining studies included composite SES indices. Household income (9) and parental education (8) were frequently evaluated. The significance of the effect modifier was found in nine studies that demonstrated a higher risk for individuals living in a lower SES. Sources of heterogeneity included SES measurement, health outcomes and geographical aggregation. CONCLUSIONS: The results suggest a higher modification in the effect of SES, generally indicating greater risk for children in lower SES. Children's characteristics need to be more carefully theorized and measured in this area, including the use of transdisciplinary approaches.

Space-time hot spots of critically ill small for gestational age newborns and industrial air pollutants in major metropolitan areas of Canada.

We assessed the association of spatiotemporal hot spots of critically ill small for gestational age (ciSGA) newborns and industrial air emissions. Using neonatal admission data from the Canadian Neonatal Network between 2006 and 2010 (n = 32,836 infants), we aggregated maternal residential postal codes from nineteen census metropolitan areas (CMA) into space-time cubes and applied emerging hot spot analyses. Using National Pollutant Release Inventory data (n = 161 chemicals) and Environment Canada weather station data (n = 19 sites), we estimated monthly wind-dispersion of air emissions and calculated hot spots. We associated the patterns using logistic regression, with covariates for low socioeconomic status, NO2 pollution, and number of infants. A total of 5465 infants were identified as ciSGA and the larger CMAs had more and larger hot spots (i.e. accumulation of events in space and time). Seventy-eight industrial chemical hot spots were associated with ciSGA hot spots. The highest number of positive associations were for 28 different pollutants, which differed by CMA. Twenty-one were known or suspected developmental toxicants, such as particulate matter, carbon monoxide, heavy metals, and volatile organic compounds. Associations with hot spots of industrial chemical emissions were geographically specific and may help explain the space-time trends of ciSGA.

Spatiotemporal Patterns of Small for Gestational Age and Low Birth Weight Births and Associations With Land Use and Socioeconomic Status.

In addition to small for gestational age (SGA) and low birth weight at term (LBWT), critically ill cases of SGA/LBWT are significant events from outcomes and economic perspectives that require further understanding of risk factors. We aimed to assess the spatiotemporal distribution of locations where there were consistently higher numbers of critically ill SGA/LBWT (hot spots) in comparison with all SGA/LBWT and all births. We focused on Edmonton (2008-2010) and Calgary (2006-2010), Alberta, and used a geographical information system to apply emerging hot spot analysis, as a new approach for understanding SGA, LBWT, and the critically ill counterparts (ciSGA or ciLBWT). We also compared the resulting aggregated categorical patterns with proportions of land use and socioeconomic status (SES) using Spearman correlation and logistic regression. There was an overall increasing trend in all space-time clusters. Whole period emerging hot spot patterns among births and SGA generally coincided, but SGA with ciSGA and LBWT with ciLBWT did not. Regression coefficients were highest for low SES with SGA and LBWT, but not with ciSGA and ciLBWT. Open areas and industrial land use were most associated with ciLBWT but not with ciSGA, SGA, or LBWT. Differences in the space-time hot spot patterns and the associations with ciSGA and ciLBWT indicate further need to research the interplay of maternal and environmental influences. We demonstrated the novel application of emerging hot spot analysis for small newborns and spatially related them to the surrounding environment.

Chemical composition of PM10 and its effect on in vitro hemolysis of human red blood cells (RBCs): a comparison study during dust storm and inversion.

PURPOSE: This study aimed to investigate chemical composition of PM10 (particulate matter with aerodynamic diameter ≤ 10 µm) during dust storm and inversion in Tehran and hemolysis effects. METHODS: PM10 was sampled in Tehran, Iran, during dust storm and inversion conditions. Water soluble ions (F¯, Cl¯, NO2¯, NO3¯, SO4¯2, Na+, K+, NH4 +, Ca+2, Mg+2) and elements (Al, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Se, Sn, Sr, V, Zn, Pt, Rh, Pd, As and Si) were analyzed by ion chromatograph (IC) and inductively coupled plasma optical emission spectrometer (ICP-OES), respectively. Hemolysis was examined as in vitro at PM10 concentrations of 50-300 µg/ml. RESULTS: Daily average of PM10 concentrations in dusty and inversion days were 348.40 and 220.54 µg/m3, respectively. Most prevalence ionic components were NO3¯, Cl¯, SO4¯2 and Ca+2 during dust storm and SO4¯2, NO3¯, Cl¯ and NH4 + during inversion. Si, Fe and Al had the maximum values in both conditions. Particles associated with both conditions induced hemolytic responses. PM10 from dusty day showed a higher hemolysis percent (10.24 ± 4.67%) than inversion (9.08 ± 5.47%), but this difference was not significant (p = 0.32). Hemolytic effects were significantly intensified by increased PM concentrations (p < 0.001) in a dose-response manner. CONCLUSIONS: As the results, chemical composition of sampled particles from inversion days and dust storm was different from each other. Hemolytic effects of particles during dust storm were more than inversion days. However, this difference was not statistically significant.

Interdisciplinary-driven hypotheses on spatial associations of mixtures of industrial air pollutants with adverse birth outcomes.

BACKGROUND: Adverse birth outcomes (ABO) such as prematurity and small for gestational age confer a high risk of mortality and morbidity. ABO have been linked to air pollution; however, relationships with mixtures of industrial emissions are poorly understood. The exploration of relationships between ABO and mixtures is complex when hundreds of chemicals are analyzed simultaneously, requiring the use of novel approaches. OBJECTIVE: We aimed to generate robust hypotheses spatially linking mixtures and the occurrence of ABO using a spatial data mining algorithm and subsequent geographical and statistical analysis. The spatial data mining approach aimed to reduce data dimensionality and efficiently identify spatial associations between multiple chemicals and ABO. METHODS: We discovered co-location patterns of mixtures and ABO in Alberta, Canada (2006-2012). An ad-hoc spatial data mining algorithm allowed the extraction of primary co-location patterns of 136 chemicals released into the air by 6279 industrial facilities (National Pollutant Release Inventory), wind-patterns from 182 stations, and 333,247 singleton live births at the maternal postal code at delivery (Alberta Perinatal Health Program), from which we identified cases of preterm birth, small for gestational age, and low birth weight at term. We selected secondary patterns using a lift ratio metric from ABO and non-ABO impacted by the same mixture. The relevance of the secondary patterns was estimated using logistic models (adjusted by socioeconomic status and ABO-related maternal factors) and a geographic-based assignment of maternal exposure to the mixtures as calculated by kernel density. RESULTS: From 136 chemicals and three ABO, spatial data mining identified 1700 primary patterns from which five secondary patterns of three-chemical mixtures, including particulate matter, methyl-ethyl-ketone, xylene, carbon monoxide, 2-butoxyethanol, and n-butyl alcohol, were subsequently analyzed. The significance of the associations (odds ratio > 1) between the five mixtures and ABO provided statistical support for a new set of hypotheses. CONCLUSION: This study demonstrated that, in complex research settings, spatial data mining followed by pattern selection and geographic and statistical analyses can catalyze future research on associations between air pollutant mixtures and adverse birth outcomes.

Proinflammatory effects of dust storm and thermal inversion particulate matter (PM10) on human peripheral blood mononuclear cells (PBMCs) in vitro: a comparative approach and analysis.

Particulate matter (PM) as the carcinogenic air pollutants can lead to aggravated health outcomes. Epidemiological studies demonstrated that PM can be engaged in different diseases such as cardiovascular, respiratory and cancer. The in vitro secretion of proinflammatory cytokines by human peripheral blood mononuclear cells (PBMCs) has been used to assess the effects of PM with an aerodynamic diameter < 10 µm (PM10). This study compared the proinflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and interleukin 1-beta (IL1-ß) secretions of PBMCs exposed to PM10 of dust storm and inversion. We collected PM10 samples during the spring and autumn seasons in two locations. Isolated PBMCs were exposed separately to 50, 150, and 300 µg/ml of different type of PM10 for 4 and 24 h. The mean concentrations of TNF-α for the PM of dust storm and inversion were 6305.61 ± 2421 and 6651.74 ± 2820, respectively. Also the mean concentrations of IL1-ß for the PM of dust storm and inversion were 556.86 ± 162 and 656.35 ± 196, respectively. Furthermore, these values for the production of IL-6 were 12,655 ± 5661 and 16,685 ± 8069, respectively. Although no significant difference was observed between the PM of dust storm and that of inversion with regard to PBMCs, the results showed a significant increase in the proinflammatory cytokine secretion of both PMs compared with the controls. Moreover, TNF-α, IL1-ß, and IL-6 secreted in cells exposed to PM10 of dust storm were about 10 times more than the controls, these values for cells exposed to PM10 of inversion were around 10, 12, and 14 times more than the controls, respectively. It can be concluded that the PM10 of both dust storm and inversion can play a significant role in proinflammatory cytokine secretion due to its harmful effect on human health. Graphical abstractThis picture shows the Proinflammatory cytokine producing potential of PM10 with two sources (dust storm and urban air pollution) in exposure with human PBMCs in vitro.

Correction to: Chemical composition of PM10 and its effect on in vitro hemolysis.

[This corrects the article DOI: 10.1007/s40201-018-00327-w.].

Using maps to communicate environmental exposures and health risks: Review and best-practice recommendations.

BACKGROUND: Graphical materials can be effective communication tools, and maps in particular are a potentially powerful means of conveying spatial information. Previous reviews have provided insights on the application of cartographic best practices, pitfalls to avoid, and considerations related to risk perception and communication, but none has reviewed primary studies of the effectiveness or utility of maps to users, nor have they addressed the issue from the perspective of health literacy, environmental health literacy, or public health ethics. OBJECTIVES: To systematically identify and review the literature pertaining to evaluation of maps in general, or specific map features, as environmental exposure and health risk communication tools; to formulate best-practice recommendations; and to identify future research priorities. METHODS: A health science librarian searched the literature for commentaries, reviews, and primary studies. Titles, abstracts, and full-text papers were screened for inclusion, and details of methods and results were extracted from 4 reviews and commentaries and 18 primary studies. This was supplemented by one additional review and 13 additional primary studies pertaining to use of maps for communication about wildfires and floods. One additional paper was identified by reviewing reference lists of all relevant papers. RESULTS: and Discussion: While there are significant gaps in the evidence, we formulated best practice recommendations highlighting the perspectives of health literacy and environmental health literacy. Key recommendations include: understanding the map developer's societal role and mental model underlying map design; defining, understanding and iteratively engaging with map users; informing map design using key theoretical constructs; accounting for factors affecting risk perception; adhering to risk communication principles and cartographic best practices; and considering environmental justice and public health ethics implications. Recommendations for future research are also provided.

Land use regression models to assess air pollution exposure in Mexico City using finer spatial and temporal input parameters.

The Mexico City Metropolitan Area (MCMA) is one of the largest and most populated urban environments in the world and experiences high air pollution levels. To develop models that estimate pollutant concentrations at fine spatiotemporal scales and provide improved air pollution exposure assessments for health studies in Mexico City. We developed finer spatiotemporal land use regression (LUR) models for PM2.5, PM10, O3, NO2, CO and SO2 using mixed effect models with the Least Absolute Shrinkage and Selection Operator (LASSO). Hourly traffic density was included as a temporal variable besides meteorological and holiday variables. Models of hourly, daily, monthly, 6-monthly and annual averages were developed and evaluated using traditional and novel indices. The developed spatiotemporal LUR models yielded predicted concentrations with good spatial and temporal agreements with measured pollutant levels except for the hourly PM2.5, PM10 and SO2. Most of the LUR models met performance goals based on the standardized indices. LUR models with temporal scales greater than one hour were successfully developed using mixed effect models with LASSO and showed superior model performance compared to earlier LUR models, especially for time scales of a day or longer. The newly developed LUR models will be further refined with ongoing Mexico City air pollution sampling campaigns to improve personal exposure assessments.

Mapping outdoor habitat and abnormally small newborns to develop an ambient health hazard index.

BACKGROUND: The geography of where pregnant mothers live is important for understanding outdoor environmental habitat that may result in adverse birth outcomes. We investigated whether more babies were born small for gestational age or low birth weight at term to mothers living in environments with a higher accumulation of outdoor hazards. METHODS: Live singleton births from the Alberta Perinatal Health Program, 2006-2012, were classified according to birth outcome, and used in a double kernel density estimation to determine ratios of each outcome per total births. Individual and overlay indices of spatial models of 136 air emissions and 18 land variables were correlated with the small for gestational age and low birth weight at term, for the entire province and sub-provincially. RESULTS: There were 24 air substances and land sources correlated with both small for gestational age and low birth weight at term density ratios. On the provincial scale, there were 13 air substances and 2 land factors; sub-provincial analysis found 8 additional air substances and 1 land source. CONCLUSION: This study used a combination of multiple outdoor variables over a large geographic area in an objective model, which may be repeated over time or in other study areas. The air substance-weighted index best identified where mothers having abnormally small newborns lived within areas of potential outdoor hazards. However, individual air substances and the weighted index provide complementary information.

Aeroparticles, Composition, and Lung Diseases.

Urban air pollution is a serious worldwide problem due to its impact on human health. In the past 60 years, growing evidence established a correlation between exposure to air pollutants and the developing of severe respiratory diseases. Recently particulate matter (PM) is drawing more public attention to various aspects including historical backgrounds, physicochemical characteristics, and its pathological role. Therefore, this review is focused on these aspects. The most famous air pollution disaster happened in London on December 1952; it has been calculated that more than 4,000 deaths occurred during this event. Air pollution is a complex mix of gases and particles. Gaseous pollutants disseminate deeply into the alveoli, allowing its diffusion through the blood-air barrier to several organs. Meanwhile, PM is a mix of solid or liquid particles suspended in the air. PM is deposited at different levels of the respiratory tract, depending on its size: coarse particles (PM10) in upper airways and fine particles (PM2.5) can be accumulated in the lung parenchyma, inducing several respiratory diseases. Additionally to size, the composition of PM has been associated with different toxicological outcomes on clinical and epidemiological, as well as in vivo and in vitro animal and human studies. PM can be constituted by organic, inorganic, and biological compounds. All these compounds are capable of modifying several biological activities, including alterations in cytokine production, coagulation factors balance, pulmonary function, respiratory symptoms, and cardiac function. It can also generate different modifications during its passage through the airways, like inflammatory cells recruitment, with the release of cytokines and reactive oxygen species (ROS). These inflammatory mediators can activate different pathways, such as MAP kinases, NF-κB, and Stat-1, or induce DNA adducts. All these alterations can mediate obstructive or restrictive respiratory diseases like asthma, COPD, pulmonary fibrosis, and even cancer. In 2013, outdoor air pollution was classified as Group 1 by IARC based on all research studies data about air pollution effects. Therefore, it is important to understand how PM composition can generate several pulmonary pathologies.