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Background: There is a long tradition in environmental health of using frameworks for evidence synthesis, such as those of the U.S. Environmental Protection Agency for its Integrated Science Assessments and the International Agency for Research on Cancer Monographs. The framework, Grading of Recommendations Assessment, Development, and Evaluation (GRADE), was developed for evidence synthesis in clinical medicine. The U.S. Office of Health Assessment and Translation (OHAT) elaborated an approach for evidence synthesis in environmental health building on GRADE. Methods: We applied a modified OHAT approach and a broader 'narrative' assessment to assess the level of confidence in a large systematic review on traffic-related air pollution and health outcomes. Discussion: We discuss several challenges with the OHAT approach and its implementation and suggest improvements for synthesizing evidence from observational studies in environmental health. We consider the determination of confidence using a formal rating scheme of up- and downgrading of certain factors, the treatment of every factor as equally important, and the lower initial confidence rating of observational studies to be fundamental issues in the OHAT approach. We argue that some observational studies can offer high-confidence evidence in environmental health. We note that heterogeneity in magnitude of effect estimates should generally not weaken the confidence in the evidence, and consistency of associations across study designs, populations, and exposure assessment methods may strengthen confidence in the evidence. We mention that publication bias should be explored beyond statistical methods and is likely limited when large and collaborative studies comprise most of the evidence and when accrued over several decades. We propose to identify possible key biases, their most likely direction, and their potential impacts on the results. We think that the OHAT approach and other GRADE-type frameworks require substantial modification to align better with features of environmental health questions and the studies that address them. We emphasize that a broader, 'narrative' evidence assessment based on the systematic review may complement a formal GRADE-type evaluation. https://doi.org/10.1289/EHP11532, Introduction Evidence synthesis is widely used to summarize findings of health effects studies of environmental exposures. Such syntheses are typically part of systematic reviews of observational epidemiologic study findings and [...]

OBJECTIVES: We aimed to assess the relationships between deprivation at Quebec public schools, their proximity to polluting industries, and their exposure to industrial air emission sources including ambient fine particulate matter ([PM.sub.2.5]), sulphur dioxide (S[O.sub.2]) and nitrogen dioxide (N[O.sub.2]). METHODS: We obtained four indicators of school deprivation using data from the 2006 Canadian census called the low-income threshold indicator, the neighbourhood SES indicator, and the social and material deprivation indicators of Pampalon. Using proximity spatial tools, we constructed three buffers of 2.5, 5 and 7.5 km around each school and summed up total emissions of [PM.sub.2.5], S[O.sub.2] and N[O.sub.2] for each school. Industrial air emissions were estimated using data from the 2006 Canadian National Pollutant Release Inventory. The Pearson correlations and LOESS regressions and natural log-transformed industrial air emissions were evaluated for Quebec public schools within the three buffers. RESULTS: Of the 2189 public schools in Quebec, 608 (27.8%), 1108 (50.6%) and 1384 (63.2%) schools were located near at least one industry emitting one or more pollutants of interest in buffers of 2.5 km, 5 km and 7.5 km of schools respectively. Weak positive Pearson correlations (r) were found between logtransformed tons of industrial emissions of [PM.sub.2.5], S[O.sub.2] and N[O.sub.2] and both the social deprivation (r = {0.23; 0.33}) and low-income threshold (r = {0.17; 0.29}) indicators in a buffer of 2.5 km. However, we found negative associations between emissions and the neighbourhood SES (r = {0.06; 0.16}) and material deprivation (r = {-0.04; 0.08}) indicators. CONCLUSION: Our study suggests that schools in Quebec with higher rates of socio-economic deprivation among their students may be more likely to be exposed to higher emissions of industrial air pollutants. KEY WORDS: Air pollution; child; industry; school; social class OBJECTIFS : L'objectif de cette etude etait d'explorer la relation entre le niveau de defavorisation des ecoles publiques quebecoises, leur proximite aux sources industrielles et leur exposition aux emissions industrielles de particules fines ([PM.sub.2.5]), de dioxyde de soufre (S[O.sub.2]) et d'oxydes d'azote (NOx). METHODES : L'indice de faible revenu (SFR), l'indice de milieu socioeconomique (IMSE) et les indices de defavorisation sociale et materielle de Pampalon, bases sur le recensement de 2006, ont ete utilises. Des cercles de rayons de 2,5 km, 5 km et 7,5 km ont ete construits autour des ecoles. En utilisant l'Inventaire national de rejets de polluants, les emissions industrielles de [PM.sub.2.5], S[O.sub.2] et N[O.sub.2] de l'annee 2006 ont ete sommees dans chaque rayon. Les relations entre les emissions industrielles log-transformees et la defavorisation ont ete evaluees pour les ecoles en utilisant des correlations de Pearson et des regressions LOESS. RESULTATS : Des 2189 ecoles incluses dans cette etude, 608 (27,8%), 1108 (50,6%) et 1384 (63,2%) etaient localisees a proximite d'au moins une industrie emettrice d'un ou plusieurs polluants d'interet dans un rayon de 2,5 km, 5 km et 7,5 km autour des ecoles, respectivement. Des correlations de Pearson (r) positives ont ete notees entre les tonnes d'emissions industrielles log-transformees de [PM.sub.2.5], S[O.sub.2] et N[O.sub.2] et l'indice de defavorisation sociale de Pampalon (r = {0,23; 0,33}) et le SFR (r = {0,17; 0,29}) dans un rayon de 2.5 km. Cependant des correlations contre-intuitives ont ete observees avec l'IMSE (r = {0,06; 0,16}) et l'indice de defavorisation materielle de Pampalon (r = {-0,04; 0,08}). CONCLUSION : Cette etude suggere que les ecoles quebecoises plus defavorisees pourraient etre davantage exposees aux emissions industrielles de polluants de l'air que les autres. MOTS-CLES : ecole; enfant; industrie; statut socio-economique; pollution de l'air, Primary ambient air pollutants, namely particulate matter ([PM.sub.2.5]), sulphur dioxide (S[O.sub.2]) and nitrogen dioxide (N[O.sub.2]), are largely emitted by anthropogenic sources such as vehicular traffic and industry. (1-3) Exposure to [...]

Background: Environmental factors may contribute to the development of Kawasaki disease in children, but prenatal environmental exposures are understudied. Objective: We used a population-based cohort to investigate whether prenatal exposure to outdoor air pollution is associated with the incidence of Kawasaki disease in childhood. Methods: We performed a longitudinal cohort study of all children born in Quebec, Canada, between 2006 and 2012. Children were followed for Kawasaki disease from birth until 31 March 2018. We assigned prenatal air pollutant exposure according to the residential postal code at birth. The main exposure was annual average concentration of ambient fine particulate matter [PM [less than or equal to]2.5 [micro]m in aerodynamic diameter (P[M.sub.2.5]) and nitrogen dioxide (N[O.sub.2]) from satellite-based estimates and land-use regression models. As secondary exposures, we considered industrial P[M.sub.2.5], N[O.sub.2], and sulfur dioxide (S[O.sub.2]) emissions estimated from dispersion models. We estimated hazard ratios (HRs) using Cox proportional hazards models, adjusted for maternal age, parity, sex, multiple birth, maternal smoking during pregnancy, socioeconomic status, birth year, and rural residence. We considered single and multipollutant models. We performed several sensitivity analyses, including assessing modifying effects of maternal comorbidities (e.g., diabetes, preeclampsia). Results: The cohort comprised 505,336 children, including 539 with Kawasaki disease. HRs for each interquartile range increase in ambient air pollution were 1.16 (95% CI: 0.96, 1.39) for P[M.sub.2.5] and 1.12 (95% CI: 0.96, 1.31) for N[O.sub.2]. For industrial air pollution, HRs were 1.07 (95% CI: 1.01, 1.13) for S[O.sub.2], 1.09 (95% CI: 0.99, 1.20) for N[O.sub.2], and 1.01 (95% CI: 0.97, 1.05) for P[M.sub.2.5]. In multipollutant models, associations for ambient P[M.sub.2.5] and N[O.sub.2] (i.e., from all sources) were robust to adjustment for industrial pollution, and vice versa. Discussion: In this population-based cohort study, both prenatal exposure to ambient and industrial air pollution were associated with the incidence of Kawasaki disease in childhood. Further studies are needed to consolidate the observed associations. https://doi.org/10.1289/EHP6920, Introduction Kawasaki disease is the leading cause of acquired heart disease in children in North America (Kawasaki Disease Canada 2020; McCrindle et al. 2017). Kawasaki is an autoimmune vasculitis, mostly [...]

Objective: Estimate the number of awakenings additional to spontaneous awakenings, induced by the nighttime aircraft movements at an international airport in Montreal, in the population residing nearby in 2009. Methods: Maximum sound levels ([L.sub.AS,max]) were derived from aircraft movements using the Integrated Noise Model 7.0b, on a 28 x 28 km grid centred on the airport and with a 0.1 x 0.1 km resolution. Outdoor [L.sub.AS,max] were converted to indoor [L.sub.AS,max] by reducing noise levels by 15 dB(A) or 21 dB(A). For all grid points, [L.sub.AS,max] were transformed into probabilities of additional awakening using a function developed by Basner et al. (2006). The probabilities of additional awakening were linked to estimated numbers of exposed residents for each grid location to assess the number of aircraft-noise-induced awakenings in Montreal. Results: Using a 15 dB(A) sound attenuation, 590 persons would, on average, have one or more additional awakenings per night for the year 2009. In the scenario using a 21 dB(A) sound attenuation, on average, no one would be subjected to one or more additional awakenings per night due to aircraft noise. Conclusion: Using the 2009 flight patterns, our data suggest that a small number of Montreal residents are exposed to noise levels that could induce one or more awakenings additional to spontaneous awakenings per night. Key words: Noise; sleep; aircraft, risk assessment Objectif : Estimer le nombre de reveils additionnels aux reveils spontanes, generes par les mouvements aeriens nocturnes, de la population residant a proximite d'un aeroport international sur l'ile de Montreal en 2009. Methode : Les niveaux sonores maximaux ([L.sub.AS,max]) ont ete determines a partir des mouvements aeriens suite a l'aide de l'Integrated Noise Model 7,0b pour une grille de points de 28 x 28 km centree sur l'aeroport a une resolution de 0,1 x 0,1 km. Les [L.sub.AS,max] exterieurs ont ete convertis en [L.sub.AS,max] interieurs en les reduisant de 15 dB(A) ou 21 dB(A). Ensuite les [L.sub.AS,max] de chaque point de grille ont ete transformes en probabilite de reveils additionnels a l'aide d'une fonction developpee par Basner et coll. (2006). Les probabilites de reveils additionnels calculees ont ete associees au nombre de residents se trouvant a chaque point de grille afin d'estimer les reveils additionnels lies aux mouvements aeriens a Montreal. Resultats : En utilisant l'attenuation sonore de 15 dB(A), 590 individus auraient, en moyenne, un reveil additionnel ou plus par nuit en 2009. Cependant, en utilisant l'attenuation sonore de 21 dB(A), en moyenne, aucun individu n'eprouverait un reveil additionnel ou plus par nuit. Conclusion : Selon nos resultats, issus des mouvements aeriens de 2009, un nombre restreint de Montrealais seraient exposes a des niveaux sonores pouvant induire un reveil additionnel aux reveils spontanes ou plus par nuit. Mots cles : bruit; sommeil; avion; analyse de risque, In recent years, many studies on the adverse effects of environmental noise levels have been published. Increased environmental noise levels are associated with cardiovascular diseases, (1-3) annoyance, (4) cognitive performance [...]

Objectives: Exposure to traffic-related air pollutants plays a role in several health outcomes. A large body of evidence tends to link asthma in children with traffic exposure. Increasing asthma prevalence and incidence in children in Canadian cities has been of concern for public health authorities. The following study focuses on estimating the risk of asthma prevalence attributable to residing in proximity to major roads on the Island of Montreal, Canada. Methods: Risk functions pertaining to asthma in children and residential proximity to major roads were selected from the literature and applied to Montreal. Asthma prevalence was taken from population-based studies. Population data were retrieved from Canadian census. Exposure was estimated using the proximity to major road and highway category of the Desktop Mapping Technologies Inc. database (DMTI Spatial Inc.). Results: Based on different studies, the percentage of prevalent asthma cases attributable to residing within 50 metres of a major road or highway for children aged 2, 4 and 6 years varied between 2.4% (0-4.3), 5.6% (0.1-8.6) and 5.9% (0.1-9.0). For the 5-7 year age group residing within 75 m of a major road or highway, the percent of cases was 6.4% (2.6-9.3). For children aged 8 to 10 residing within 75 m of a highway only, the percent of cases was 0.7% (0.2-0.9). Conclusion: These numbers represent the best crude estimates and are an indication of a possible range of cases linked to residential proximity to major roads. As there are uncertainties linked to the application of exposure-response functions, these estimates will be reassessed as new evidence is gathered through further research. Key words: Asthma; attributable risks; children; traffic; air pollutants La traduction du resume se trouve a la fin de l'article. Objectif : L'exposition aux polluants atmospheriques lies au trafic routier contribue a plusieurs resultats sanitaires. De nombreuses preuves tendent a lier l'asthme chez les enfants a l'exposition au trafic routier. La prevalence et l'incidence croissantes de l'asthme chez les enfants dans les villes du Canada preoccupent les autorites de sante publique. Nous avons estime le risque de prevalence de l'asthme imputable au fait de resider a proximite de grandes arteres sur l'ile de Montreal, au Canada. Methode : Nous avons selectionne dans la litterature scientifique et applique a Montreal les fonctions de risque afferentes a l'asthme chez les enfants et au fait d'habiter a proximite de grandes arteres. La prevalence de l'asthme vient d'une etude populationnelle. Les donnees demographiques sont extraites du Recensement du Canada. Nous avons estime l'exposition a l'aide d'une categorie de la base de donnees de Desktop Mapping Technologies Inc. (DMTI Spatial Inc.): << proximite de grandes routes et arteres >>. Resultats : D'apres differentes etudes, le pourcentage de prevalence des cas d'asthme imputable au fait de vivre a moins de 50 metres d'une grande route ou artere, pour les enfants de 2, 4 et 6 ans, variait entre 2,4% (0-4,3), 5,6% (0,1-8,6) et 5,9% (0,1-9,0). Dans le groupe des 5 a 7 ans vivant a moins de 75 m d'une grande route ou artere, le pourcentage de cas etait de 6,4% (2,6-9,3). Chez les enfants de 8 a 10 ans vivant a moins de 75 m d'une route seulement, le pourcentage de cas etait de 0,7% (0,2-0,9). Conclusion : Ces chiffres representent les meilleures estimations brutes et pourraient indiquer un eventail de cas lies au fait de resider a proximite d'une grande route. Il y a cependant des incertitudes liees a l'application des fonctions exposition-reaction; ces estimations seront donc reevaluees a mesure que les chercheurs reuniront de nouvelles preuves. Mots cles : asthme; risques attribuables; enfant; trafic routier; polluants atmospheriques, Vehicle traffic emissions result in a complex mixture of carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (mainly ultra-fine particles) and air toxics (1,3-butadiene, benzene, formaldehyde, polycyclic aromatic hydrocarbons-PAHs). For [...]

BACKGROUND: Systemic lupus erythematosus (SLE) is a chronic disease of unclear etiology, characterized by an overactive immune system and the production of antibodies that may target normal tissues of many [...]

BACKGROUND: Associations between air pollution and a multitude of health effects are now well established. Given ubiquitous exposure to some level of air pollution, the attributable health burden can be [...]

Background: Epidemiological studies have provided strong evidence that fine particulate matter ([PM.sub.2.5]; aerodynamic diameter < 2.5 µm) can exacerbate asthmatic symptoms in children. Pro-oxidant components of [PM.sub.2.5] are capable of directly generating reactive oxygen species. Oxidative burden is used to describe the capacity of [PM.sub.2.5] to generate reactive oxygen species in the lung. Objective: In this study we investigated the association between airway inflammation in asthmatic children and oxidative burden of [PM.sub.2.5] personal exposure. Methods: Daily [PM.sub.2.5] personal exposure samples (n = 249) of 62 asthmatic school-aged children in Montreal were collected over 10 consecutive days. The oxidative burden of [PM.sub.2.5] samples was determined in vitro as the depletion of low-molecular-weight antioxidants (ascorbate and gluta-thione) from a synthetic model of the fluid lining the respiratory tract. Airway inflammation was measured daily as fractional exhaled nitric oxide (FeNO). Results: A positive association was identified between FeNO and glutathione-related oxidative burden exposure in the previous 24 hr (6.0% increase per interquartile range change in glutathione). Glutathione-related oxidative burden was further found to be positively associated with FeNO over 1-day lag and 2-day lag periods. Results further demonstrate that corticosteroid use may reduce the FeNO response to elevated glutathione-related oxidative burden exposure (no use, 15.8%; irregular use, 3.8%), whereas mold (22.1%), dust (10.6%), or fur (13.1%) allergies may increase FeNO in children with versus children without these allergies (11.5%). No association was found between [PM.sub.2.5] mass or ascorbate-related oxidative burden and FeNO levels. CONCLUSIONS: Exposure to [PM.sub.2.5] with elevated glutathione-related oxidative burden was associated with increased FeNO. http://dx.doi.org/10.1289/EHP175, Background The prevalence of asthma in children has increased over the past decade in developed countries (CDC 2011). Environmental factors may contribute to the development of paediatric asthma, including allergens, [...]

BACKGROUND: Although it is well established that air pollutants can exacerbate asthma, the link with new asthma onset in children is less clear. OBJECTIVE: We assessed the association between the onset of childhood asthma with both time of birth and time-varying exposures to outdoor air pollutants. METHOD: An open cohort of children born in the province of Quebec, Canada, was created using linked medical-administrative databases. New cases of asthma were defined as one hospital discharge with a diagnosis of asthma or two physician claims for asthma within a 2 year period. Annual ozone ([O.sub.3]) levels were estimated at the child's residence for all births 1999-2010, and nitrogen dioxide (N[O.sub.2]) levels during 1996-2006 were estimated for births on the Montreal Island. Satellite based concentrations of fine particles (P[M.sub.2.5]) were estimated at a 10 km x 10 km resolution and assigned to residential postal codes throughout the province (1996-2011). Hazard ratios (HRs) were assessed with Cox models for the exposure at the birth address and for the time-dependent exposure. We performed an indirect adjustment for secondhand smoke (SHS). RESULTS: We followed 1,183,865 children (7,752,083 person-years), of whom 162,752 became asthmatic. After controlling for sex and material and social deprivation, HRs for an interquartile range increase in exposure at the birth address to N[O.sub.2] (5.45 ppb), [O.sub.3] (3.22 ppb), and P[M.sub.2.5] (6.50 µg/[m.sup.3]) were 1.04 (95% CI: 1.02, 1.05), 1.11 (95% CI: 1.10, 1.12), and 1.31 (95% CI: 1.28, 1.33), respectively. Effects of [O.sub.3] and P[M.sub.2.5] estimated with time-varying Cox models were similar to those estimated using exposure at birth, whereas the effect of N[O.sub.2] was slightly stronger (HR = 1.07; 95% CI: 1.05, 1.09). CONCLUSIONS: Asthma onset in children appears to be associated with residential exposure to P[M.sub.2.5], [O.sub.3] and N[O.sub.2]. http://dx.doi.org/10.1289/ehp.1509838, Introduction Asthma is one of the most common childhood chronic diseases worldwide (Asher et al. 2006; Garner and Kohen 2008; Williams et al. 1999). Although the link between exposure to [...]

Background: Climate change may lead to more severe and extreme heat waves in the future, but its potential impact on sudden infant death--a leading cause of infant mortality--is unclear. Objectives: We sought to determine whether risk of sudden infant death syndrome (SIDS) is elevated during hot weather. Methods: We undertook a case-crossover analysis of all sudden infant deaths during warm periods in metropolitan Montreal, Quebec, Canada, from 1981 through 2010. Our analysis included a total of 196 certified cases of SIDS, including 89 deaths at 1-2 months of age, and 94 at 3-12 months. We estimated associations between maximum outdoor temperatures and SIDS by comparing outdoor temperatures on the day of or day before a SIDS event with temperatures on control days during the same month, using cubic splines to model temperature and adjusting for relative humidity. Results: Maximum daily temperatures of > 29[degrees]C on the same day were associated with 2.78 times greater odds of sudden infant death relative to 20[degrees]C (95% CI: 1.64, 4.70). The likelihood of sudden death increased steadily with higher temperature. Associations were stronger for infants 3-12 months of age than for infants 1-2 months of age, with odds ratios of 3.90 (95% CI: 1.87, 8.13) and 1.73 (95% CI: 0.80, 3.73), respectively, for 29[degrees]C compared with 20[degrees]C on the day of the event. Conclusions: High ambient temperature may be a novel risk factor for SIDS, especially at [greater than or equal to] 3 months of age. Climate change and the higher temperatures that result may account for a potentially greater proportion of sudden infant deaths in the future., Introduction Sudden infant death syndrome (SIDS) is a leading cause of death among infants 1-12 months of age, but its underlying risk factors are poorly understood (Kinney and Thach 2009; [...]

Background: Ambient air ozone ([O.sub.3]) is a pulmonary irritant that has been associated with respiratory health effects including increased lung inflammation and permeability, airway hyperreactivity, respiratory symptoms, and decreased lung function. Estimation of [O.sub.3] exposure is a complex task because the pollutant exhibits complex spatiotemporal patterns. To refine the quality of exposure estimation, various spatiotemporal methods have been developed worldwide. OBJECTIVES: We sought to compare the accuracy of three spatiotemporal models to predict summer ground-level [O.sub.3] in Quebec, Canada. METHODS: We developed a land-use mixed-effects regression (LUR) model based on readily available data (air quality and meteorological monitoring data, road networks information, latitude), a Bayesian maximum entropy (BME) model incorporating both [O.sub.3] monitoring station data and the land-use mixed model outputs (BME-LUR), and a kriging method model based only on available [O.sub.3] monitoring station data (BME kriging). We performed leave-one-station-out cross-validation and visually assessed the predictive capability of each model by examining the mean temporal and spatial distributions of the average estimated errors. RESULTS: The BME-LUR was the best predictive model ([R.sup.2] = 0.653) with the lowest root means-quare error (RMSE ;7.06 ppb), followed by the LUR model ([R.sup.2] = 0.466, RMSE = 8.747) and the BME kriging model ([R.sup.2] = 0.414, RMSE = 9.164). CONCLUSIONS: Our findings suggest that errors of estimation in the interpolation of [O.sub.3] concentrations with BME can be greatly reduced by incorporating outputs from a LUR model developed with readily available data. http://dx.doi.org/10.1289/ehp.1306566, Introduction Tropospheric ozone ([O.sub.3]) is a photochemical pollutant that has increased globally in concentration since the 19th century (Bogaert et al. 2009). Short- and long-term exposure to ambient [O.sub.3] has [...]

Dear Editor: Risk estimates are frequently used in public health practice to guide authorities responsible for adopting policies that protect public health. There are uncertainties in all risk estimates, most [...]

Objective To estimate the association between fine particulate (PM 2.5 ) and nitrogen dioxide (NO 2 ) pollution and systemic autoimmune rheumatic diseases (SARDs). Methods Associations between ambient air pollution (PM 2.5 and NO 2 ) and SARDs were assessed using land-use regression models for Calgary, Alberta and administrative health data (1993–2007). SARD case definitions were based on ≥ 2 physician claims, or ≥ 1 rheumatology billing code; or ≥ 1 hospitalization code (for systemic lupus, Sjogren's Syndrome, scleroderma, polymyositis, dermatomyositis, or undifferentiated connective tissue disease). Bayesian hierarchical latent class regression models estimated the probability that each resident was a SARD case, based on these case definitions. The sum of individual level probabilities provided the estimated number of cases in each area. The latent class model included terms for age, sex, and an interaction term between age and sex. Bayesian logistic regression models were used to generate adjusted odds ratios (OR) for NO 2 and PM 2.5 . pollutant models, adjusting for neighbourhood income, age, sex, and an interaction between age and sex. We also examined models stratified for First-Nations (FN) and non-FN subgroups. Results Residents that were female and/or aged >45 had a greater probability of being a SARD case, with the highest OR estimates for older females. Independently, the odds of being a SARDs case increased with PM 2.5 levels, but the results were inconclusive for NO 2 . The results stratified by FN and non-FN groups were not distinctly different. Conclusion In this urban Canadian sample, adjusting for demographics, exposure to PM 2.5 was associated with an increased risk of SARDs. The results for NO 2 were inconclusive. [ABSTRACT FROM AUTHOR]

Abstract: Little is known about the level and content of exposure to fine particles (PM2.5) among persons who attend fireworks displays and those who live nearby. An evaluation of the levels of PM2.5 and their elemental content was carried out during the nine launches of the 2007 Montréal International Fireworks Competition. For each event, a prediction of the location of the firework plume was obtained from the Canadian Meteorological Centre (CMC) of the Meteorological Service of Canada. PM2.5 was measured continuously with a photometer (Sidepak™, TSI) within the predicted plume location (“predicted sites”), and integrated samples were collected using portable personal samplers. An additional sampler was located on a nearby roof (“fixed site”). The elemental composition of the collected PM2.5 samples from the “predicted sites” was determined using both a non-destructive energy dispersive ED-XRF method and an ICP-MS method with a near-total microwave-assisted acid digestion. The elemental composition of the “fixed site” samples was determined by the ICP-MS with the near-total digestion method. The highest PM2.5 levels reached nearly 10 000 μg m−3, roughly 1000 times background levels. Elements such as K, Cl, Al, Mg and Ti were markedly higher in plume-exposed filters. This study shows that 1) persons in the plume and in close proximity to the launch site may be exposed to extremely high levels of PM2.5 for the duration of the display and, 2) that the plume contains specific elements for which little is known of their acute cardio-respiratory toxicity. [Copyright &y& Elsevier]