Competencies for Transformational Leadership in Public Health-An International Delphi Consensus Study.

Objectives: This Delphi study intended to develop competencies for transformational leadership in public health, including behavioral descriptions (descriptors) tailored to individuals and their contexts. Methods: The study involved five rounds, including online "e-Delphi" consultations and real-time online workshops with experts from diverse sectors. Relevant competencies were identified through a literature review, and experts rated, ranked, rephrased, and proposed descriptors. The study followed the Guidance on Conducting and REporting DElphi Studies (CREDES) and the COmpeteNcy FramEwoRk Development in Health Professions (CONFERD-HP) reporting guidelines. Results: Our framework comprises ten competencies for transformational public health leadership (each with its descriptors) within four categories, and also describes a four-stage model for developing relevant competencies tailored to different contexts. Conclusion: Educators responsible for curriculum design, particularly those aiming to align curricula with local goals, making leadership education context-specific and -sensitive, may benefit from the proposed framework. Additionally, it can help strengthen links between education and workforce sectors, address competency gaps, and potentially reduce the out-migration of graduates in the health professions.

Stringency of COVID-19 Containment Response Policies and Air Quality Changes: A Global Analysis across 1851 Cities.

The COVID-19 containment response policies (CRPs) had a major impact on air quality (AQ). These CRPs have been time-varying and location-specific. So far, despite having numerous studies on the effect of COVID-19 lockdown on AQ, a knowledge gap remains on the association between stringency of CRPs and AQ changes across the world, regions, nations, and cities. Here, we show that globally across 1851 cities (each more than 300 000 people) in 149 countries, after controlling for the impacts of relevant covariates (e.g., meteorology), Sentinel-5P satellite-observed nitrogen dioxide (NO2) levels decreased by 4.9% (95% CI: 2.2, 7.6%) during lockdowns following stringent CRPs compared to pre-CRPs. The NO2 levels did not change significantly during moderate CRPs and even increased during mild CRPs by 2.3% (95% CI: 0.7, 4.0%), which was 6.8% (95% CI: 2.0, 12.0%) across Europe and Central Asia, possibly due to population avoidance of public transportation in favor of private transportation. Among 1768 cities implementing stringent CRPs, we observed the most NO2 reduction in more populated and polluted cities. Our results demonstrate that AQ improved when and where stringent COVID-19 CRPs were implemented, changed less under moderate CRPs, and even deteriorated under mild CRPs. These changes were location-, region-, and CRP-specific.

Evidence From the Decade of Action for Road Safety: A Systematic Review of the Effectiveness of Interventions in Low and Middle-Income Countries.

Objectives: To evaluate the effectiveness of road safety interventions in low and middle-income countries (LMICs), considering the principles of systems theory presented in the Global Plan for the Decade of Action for Road Safety. Methods: We conducted a systematic review according to PRISMA guidelines. We searched for original research studies published during 2011-2019 in the following databases: Medline, Embase, PsycInfo, Scopus, Web of Science, Cochrane library, Global Health Library, ProQuest and TRID. We included studies conducted in LMICs, evaluating the effects of road traffic safety interventions and reporting health-related outcomes. Results: Of 12,353 non-duplicate records, we included a total of 33 studies. Most interventions were related to legislation and enforcement (n = 18), leadership (n = 5) and speed management (n = 4). Overall, legislation and enforcement interventions appear to have the largest impact. Few studies were found for road infrastructure, vehicle safety standard and post crash response interventions. Conclusion: Based on the currently available evidence, legislation and enforcement interventions appear most impactful in LMICs. However, many interventions remain understudied and more holistic approaches capturing the complexity of road transport systems seem desirable. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=197267, identifier CRD42020197267.

Residential air pollution does not modify the positive association between physical activity and lung function in current smokers in the ECRHS study.

BACKGROUND: Very few studies have examined whether a long-term beneficial effect of physical activity on lung function can be influenced by living in polluted urban areas. OBJECTIVE: We assessed whether annual average residential concentrations of nitrogen dioxide (NO2) and particulate matter with aerodynamic diameters < 2.5 µm (PM2.5) and <10 µm (PM10) modify the effect of physical activity on lung function among never- (N = 2801) and current (N = 1719) smokers in the multi-center European Community Respiratory Health Survey. METHODS: Associations between repeated assessments (at 27-57 and 39-67 years) of being physically active (physical activity: ≥2 times and ≥1 h per week) and forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were evaluated using adjusted mixed linear regression models. Models were conducted separately for never- and current smokers and stratified by residential long-term NO2, PM2.5 mass and PM10 mass concentrations (≤75th percentile (low/medium) versus >75th percentile (high)). RESULTS: Among current smokers, physical activity and lung function were positively associated regardless of air pollution levels. Among never-smokers, physical activity was associated with lung function in areas with low/medium NO2, PM2.5 mass and PM10 mass concentrations (e.g. mean difference in FVC between active and non-active subjects was 43.0 mL (13.6, 72.5), 49.5 mL (20.1, 78.8) and 49.7 mL (18.6, 80.7), respectively), but these associations were attenuated in high air pollution areas. Only the interaction term of physical activity and PM10 mass for FEV1 among never-smokers was significant (p-value = 0.03). CONCLUSIONS: Physical activity has beneficial effects on adult lung function in current smokers, irrespective of residential air pollution levels in Western Europe. Trends among never-smokers living in high air pollution areas are less clear.

Is there a gender-specific association between asthma and carotid intima media thickness in Swiss adolescents?

Respiratory diseases are associated with increased cardiovascular risk in adults, but little is known on the early impact on the vasculature in youth. The SAPALDIA Youth study, the offspring study of the Swiss Study on Air Pollution and Lung and Heart Disease In Adults (SAPALDIA), investigated the association between physician-diagnosed asthma status and common carotid artery intima media thickness (CIMT). Offspring underwent standardized clinical protocols and provided information on early life factors, health, and lifestyle. The association between per subject averages of CIMT and asthma was estimated using mixed linear regression analyses adjusting for main confounders, testing for interaction with gender and age. Of 257 offspring (mean age 15 years, 53% female), 11.5% reported doctor-diagnosed asthma (male 17%, female 7%). Mean CIMT was significantly different by gender (male 0.53 mm (± 0.045), female 0.50 mm (± 0.048); p < 0.001). Interaction was highly significant by gender (p = 0.001) with significantly increased CIMT in asthmatic vs. non-asthmatics boys (difference 0.023 mm, 95% CI 0.003; 0.043), as compared to girls. CONCLUSION: Our study suggests an increased risk for early vascular change in adolescent asthmatic boys. Whereas the small number of girls limits the interpretation, the result necessitates further research into sex-specific atherosclerotic burden related to respiratory health in adolescence. What is Known: • Evidence points to a significant impact of adult respiratory disease on cardiovascular health indicators as well as on endpoints. • Inflammation is a key pathway in vascular change across the life course. What is New: • We observe an adverse association between physician-diagnosed asthma and carotid intima media thickness in adolescent boys. • Albeit a limited number of asthmatic girls, we hypothesize the gender typical timing of asthma or a higher male cardiovascular vulnerability as possible explanations for the gender-specific results.

A joint ERS/ATS policy statement: what constitutes an adverse health effect of air pollution? An analytical framework.

The American Thoracic Society has previously published statements on what constitutes an adverse effect on health of air pollution in 1985 and 2000. We set out to update and broaden these past statements that focused primarily on effects on the respiratory system. Since then, many studies have documented effects of air pollution on other organ systems, such as on the cardiovascular and central nervous systems. In addition, many new biomarkers of effects have been developed and applied in air pollution studies.This current report seeks to integrate the latest science into a general framework for interpreting the adversity of the human health effects of air pollution. Rather than trying to provide a catalogue of what is and what is not an adverse effect of air pollution, we propose a set of considerations that can be applied in forming judgments of the adversity of not only currently documented, but also emerging and future effects of air pollution on human health. These considerations are illustrated by the inclusion of examples for different types of health effects of air pollution.

Public health impacts of city policies to reduce climate change: findings from the URGENCHE EU-China project.

BACKGROUND: Climate change is a global threat to health and wellbeing. Here we provide findings of an international research project investigating the health and wellbeing impacts of policies to reduce greenhouse gas emissions in urban environments. METHODS: Five European and two Chinese city authorities and partner academic organisations formed the project consortium. The methodology involved modelling the impact of adopted urban climate-change mitigation transport, buildings and energy policy scenarios, usually for the year 2020 and comparing them with business as usual (BAU) scenarios (where policies had not been adopted). Carbon dioxide emissions, health impacting exposures (air pollution, noise and physical activity), health (cardiovascular, respiratory, cancer and leukaemia) and wellbeing (including noise related wellbeing, overall wellbeing, economic wellbeing and inequalities) were modelled. The scenarios were developed from corresponding known levels in 2010 and pre-existing exposure response functions. Additionally there were literature reviews, three longitudinal observational studies and two cross sectional surveys. RESULTS: There are four key findings. Firstly introduction of electric cars may confer some small health benefits but it would be unwise for a city to invest in electric vehicles unless their power generation fuel mix generates fewer emissions than petrol and diesel. Second, adopting policies to reduce private car use may have benefits for carbon dioxide reduction and positive health impacts through reduced noise and increased physical activity. Third, the benefits of carbon dioxide reduction from increasing housing efficiency are likely to be minor and co-benefits for health and wellbeing are dependent on good air exchange. Fourthly, although heating dwellings by in-home biomass burning may reduce carbon dioxide emissions, consequences for health and wellbeing were negative with the technology in use in the cities studied. CONCLUSIONS: The climate-change reduction policies reduced CO2 emissions (the most common greenhouse gas) from cities but impact on global emissions of CO2 would be more limited due to some displacement of emissions. The health and wellbeing impacts varied and were often limited reflecting existing relatively high quality of life and environmental standards in most of the participating cities; the greatest potential for future health benefit occurs in less developed or developing countries.

Infectious diseases are associated with carotid intima media thickness in adolescence.

OBJECTIVE: Inflammatory risk factors in childhood, e.g. obesity, impact on carotid artery intima media thickness (CIMT), an early indicator of atherosclerosis. Little is known on potential infectious origins in childhood. We investigated the association between number of reported different childhood infectious diseases and CIMT in adolescence. STUDY DESIGN: 288 SAPALDIA offspring (8-21years) underwent a clinical examination in 2010-2011: anthropometry, blood pressure, CIMT, blood draw (cardiovascular biomarkers, cotinine). Offspring and parents gave information on individuals' and family health, child's vaccination status, infectious diseases and other early life factors. Life-time prevalence of bronchitis, pneumonia, tonsillitis, otitis, mononucleosis, meningitis, appendicitis, and scarlet fever were investigated, separately, and as cumulative infectious disease score. Multilevel adjusted linear regression analysis on the association between subjects' CIMT average and infectious diseases score was performed, stratifying by sex. RESULTS: Youth (mean age 14.8 yrs; 53% female) reported on average 1.3 of the listed infectious diseases; 22% boys and 15% girls reported ≥3 infectious diseases (p = 0.136). Two-thirds were vaccinated according to recommendations (boys 56%, girls 61.5%, p = 0.567). Sex-stratified analyses yielded significantly increased CIMT in boys with ≥3 infectious diseases vs. none (0.046 mm, 95%CI 0.024; 0.068). In girls, the effect was of same direction but statistically non-significant (0.011 mm, 95%CI -0.015; 0.036). CONCLUSION: The SAPALDIA Youth study complements current evidence on infectious origins of atherosclerosis in adults. The larger effects observed in boys may relate to a higher vulnerability of the vasculature and/or to infectious pathogens. Our data are suggestive of an early impact of childhood infectious diseases on vascular health.

Asthma, COPD and overlap syndrome: a longitudinal study in young European adults.

We compared risk factors and clinical characteristics, 9-year lung function change and hospitalisation risk across subjects with the asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS), asthma or COPD alone, or none of these diseases.Participants in the European Community Respiratory Health Survey in 1991-1993 (aged 20-44 years) and 1999-2001 were included. Chronic airflow obstruction was defined as pre-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity

Spirometer Replacement and Serial Lung Function Measurements in Population Studies: Results From the SAPALDIA Study.

The Swiss Cohort Study on Air Pollution and Lung and Heart Disease in Adults (SAPALDIA), a population cohort study, used heated-wire spirometers in 1991 and 2002 and then ultrasonic spirometers in 2010 revealing measurement bias in healthy never smokers. To provide a practical method to control for measurement bias given the replacement of spirometer in long-term population studies, we built spirometer-specific reference equations from healthy never smokers participating in 1991, 2002, and 2010 to derive individualized corrections terms. We compared yearly lung function decline without corrections terms with fixed terms that were obtained from a quasi-experimental study and individualized terms. Compared with baseline reference equations, spirometer-specific reference equations predicted lower lung function. The mean measurement bias increased with age and height. The decline in forced expiratory volume in 1 second during the reference period of 1991-2002 was 31.5 (standard deviation (SD), 28.7) mL/year while, after spirometer replacement, uncorrected, corrected by fixed term, and individualized term, the declines were 47.0 (SD, 30.1), 40.4 (SD, 30.1), and 30.4 (SD, 29.9) mL/year, respectively. In healthy never smokers, ultrasonic spirometers record lower lung function values than heated-wire spirometers. This measurement bias is sizeable enough to be relevant for researchers and clinicians. Future reference equations should account for not only anthropometric variables but also spirometer type. We provide a novel method to address spirometer replacement in cohort studies.

Early detection of subjects at risk for vascular remodelling - results from the Swiss population-based study SAPALDIA.

QUESTIONS UNDER STUDY: As the burden of cardiovascular disease (CVD) increases globally, its prevention and risk assessment becomes ever more important. We thus investigated the longitudinal association of the cardiovascular risk scores in the population-based cohort SAPALDIA with carotid intima media thickening (CIMT), an indicator of sub-clinical disease, and CVD incidence. METHODS: In 2,832 SAPALDIA participants, the Swiss and ESC heart risk score (AGLA, SCORE) were calculated based on 2001 data and CIMT was measured in 2010/11. We ran multi-level linear regression analyses between scores and CIMT, stratified for CVD status and gender, and logistic analyses for doctor-diagnosed CVD incidence. Path analyses investigated direct and indirect effects on CIMT. RESULTS: AGLA and SCORE were positively associated with increasing CIMT in both healthy and CVD diagnosed subjects and men and women. Participants in highest risk categories showed a significant CIMT difference of >0.20 mm compared to the reference risk category (<1%), even larger in CVD healthy subjects and men. With increasing risk the odds of CVD incidence increased (Ref. <1%; 10 yr. risk AGLA >10% OR 2.1, >20% OR 3.7). Path analyses yield risk factors' direct and indirect effects through blood pressure. CONCLUSION: The positive longitudinal association between risk estimations and CIMT confirms the use of risk scores in assessing individuals and populations at risk. Systolic blood pressure appears to be a main pathological mechanism, underscoring the importance of optimal blood pressure control and the importance of prevention strategies of risk factors, indirectly affecting CIMT through the haemodynamic pathway.

Atherogenesis in youth--early consequence of adolescent smoking.

BACKGROUND: Cigarette smoking is a prevalent risk behavior among adolescents and tracks into adulthood. Little is known on the early impact of smoking on the vasculature in adolescence, although smoking is considered highly atherogenic in adults. We investigated the association between active smoking and Carotid artery Intima Media Thickness (CIMT), an early indicator of atherosclerosis. METHODS AND RESULTS: The SAPALDIA Youth Study is a nested study involving 356 offspring (8-20 yrs) of the Swiss SAPALDIA cohort who reported on early life, health and lifestyle, smoking habits and disease history. 288 youth underwent clinical examination. Mean average and maximum CIMT were calculated across all images of right and left common carotid. Multi-level linear regression was performed with weekly smoking, daily number of cigarettes and serum cotinine, adjusting for participant's and parental confounders. Valid CIMT data was available in 275 offspring (mean age 15 yrs, 53% girls). Weekly smoking was reported by 10% and current parental smoking by 24%. Individual mean and maximal CIMT averaged to 0.52 mm (sd 0.05) and 0.60 mm (sd. 0.05), respectively. Regression analyses yielded significant increase in average CIMT (mm) in weekly smokers (0.025, 95% CI 0.006; 0.045), per cigarette/day (0.003, 95% CI 0.001; 0.005) and serum cotinine level (0.008/100 µg/l, 95% CI 0.002; 0.015), which remained consistent after adjusting for parental confounders. CONCLUSION: Our study yields evidence of an early adverse impact of active tobacco exposure on atherogenesis in adolescents, independent of parental smoking, underlining the public health importance of prevention of adolescent smoking.

Role of highway traffic on spatial and temporal distributions of air pollutants in a Swiss Alpine valley.

Traffic-related air pollutants show high spatial variability near roads, posing a challenge to adequately assess exposures. Recent modeling approaches (e.g. dispersion models, land-use regression (LUR) models) have addressed this but mostly in urban areas where traffic is abundant. In contrast, our study area was located in a rural Swiss Alpine valley crossed by the main North-south transit highway of Switzerland. We conducted an extensive measurement campaign collecting continuous nitrogen dioxide (NO2), particulate number concentrations (PN), daily respirable particulate matter (PM10), elemental carbon (EC) and organic carbon (OC) at one background, one highway and seven mobile stations from November 2007 to June 2009. Using these measurements, we built a hybrid model to predict daily outdoor NO2 concentrations at residences of children participating in an asthma panel study. With the exception of OC, daily variations of the pollutants followed the temporal trends of heavy-duty traffic counts on the highway. In contrast, variations of weekly/seasonal means were strongly determined by meteorological conditions, e.g., winter inversion episodes. For pollutants related to primary exhaust emissions (i.e. NO2, EC and PN) local spatial variation strongly depended on proximity to the highway. Pollutant concentrations decayed to background levels within 150 to 200 m from the highway. Two separate daily NO2 prediction models were built using LUR approaches with (a) short-term traffic and weather data (model 1) and (b) subsequent addition of daily background NO2 to previous model (model 2). Models 1 and 2 explained 70% and 91% of the variability in outdoor NO2 concentrations, respectively. The biweekly averaged predictions from the final model 2 agreed very well with the independent biweekly integrated passive measurements taken at thirteen homes and nine community sites (validation R(2)=0.74). The excellent spatio-temporal performance of our model provides a very promising basis for the health effect assessment of the panel study.

The influence of sensitisation to pollens and moulds on seasonal variations in asthma attacks.

No large study has described the seasonal variation in asthma attacks in population-based asthmatics in whom sensitisation to allergen has been measured. 2,637 young adults with asthma living in 15 countries reported the months in which they usually had attacks of asthma and had skin-prick tests performed. Differences in seasonal patterns by sensitisation status were assessed using generalised estimating equations. Most young adults with asthma reported periods of the year when their asthma attacks were more common (range: 47% in Sweden to 86% in Spain). Seasonal variation in asthma was not modified by sensitisation to house dust mite or cat allergens. Asthmatics sensitised to grass, birch and Alternaria allergens had different seasonal patterns to those not sensitised to each allergen, with some geographical variation. In southern Europe, those sensitised to grass allergens were more likely to report attacks occurred in spring or summer than in winter (OR March/April 2.60, 95% CI 1.70-3.97; OR May/June 4.43, 95% CI 2.34-8.39) and smaller later peaks were observed in northern Europe (OR May/June 1.25, 95% CI 0.60-2.64; OR July/August 1.66, 95% CI 0.89-3.10). Asthmatics reporting hay fever but who were not sensitised to grass showed no seasonal variations. Seasonal variations in asthma attacks in young adults are common and are different depending on sensitisation to outdoor, but not indoor, allergens.

Birth weight and carotid artery intima-media thickness.

OBJECTIVES: To determine the association between birth weight and carotid artery intima-media thickness (CIMT), a measure of atherogenesis, in a population of 11-year-old children. STUDY DESIGN: CIMT measured by high-resolution ultrasound, and birth registry data were available for 670 children of the Southern California Children's Health Study. Multivariate regression analyses were performed to investigate the association between birth weight and CIMT, with adjustment for child's health status and lifestyle, pregnancy information, and parental health. RESULTS: Mean CIMT was 0.57 mm (SD 0.04). We found a nonlinear association between birth weight and CIMT, with an increase in CIMT of 0.014 mm in the fifth (P value .01) compared with the third birth weight quintile. These associations were robust in subsample analyses in children considered normal-weight by gestational age or in term-born children. No significant association with CIMT was found for the lowest quintile. CONCLUSIONS: Greater birth weight was significantly associated with increased CIMT at age 11 years. No evidence for an impact of lower birth weight was found. The predictive value of childhood CIMT on future cardiovascular outcomes is largely unknown, but strong associations between childhood cardiovascular disease risk factors and adult vascular disease suggest that increased CIMT in childhood may be clinically important.

Gender differences in prevalence, diagnosis and incidence of allergic and non-allergic asthma: a population-based cohort.

BACKGROUND: Although women with severe non-allergic asthma may represent a substantial proportion of adults with asthma in clinical practice, gender differences in the incidence of allergic and non-allergic asthma have been little investigated in the general population. METHODS: Gender differences in asthma prevalence, reported diagnosis and incidence were investigated in 9091 men and women randomly selected from the general population and followed up after 8-10 years as part of the European Community Respiratory Health Survey. The protocol included assessment of bronchial responsiveness, IgE specific to four common allergens and skin tests to nine allergens. RESULTS: Asthma was 20% more frequent in women than in men over the age of 35 years. Possible under-diagnosis of asthma appeared to be particularly frequent among non-atopic individuals, but was as frequent in women as in men. The follow-up of subjects without asthma at baseline showed a higher incidence of asthma in women than in men (HR 1.94; 95% CI 1.40 to 2.68), which was not explained by differences in smoking, obesity or lung function. More than 60% of women and 30% of men with new-onset asthma were non-atopic. The incidence of non-allergic asthma was higher in women than in men throughout all the reproductive years (HR 3.51; 95% CI 2.21 to 5.58), whereas no gender difference was observed for the incidence of allergic asthma. CONCLUSIONS: This study shows that female sex is an independent risk factor for non-allergic asthma, and stresses the need for more careful assessment of possible non-allergic asthma in clinical practice, in men and women.

Risk factors for chronic obstructive pulmonary disease in a European cohort of young adults.

RATIONALE: Few studies have investigated the factors associated with the early inception of chronic obstructive pulmonary disease (COPD). OBJECTIVES: We investigated COPD risk factors in an international cohort of young adults using different spirometric definitions of the disease. METHODS: We studied 4,636 subjects without asthma who had prebronchodilator FEV(1)/FVC measured in the European Community Respiratory Health Survey both in 1991 to 1993 (when they were 20-44 yr old) and in 1999 to 2002. COPD was defined according to the Global Initiative for Chronic Obstructive Lung Disease fixed cut-off criterion (FEV(1)/FVC < 0.70), and two criteria based on the Quanjer and LuftiBus reference equations (FEV(1)/FVC less than lower limit of normal). COPD determinants were studied using two-level Poisson regression models. MEASUREMENTS AND MAIN RESULTS: COPD incidence ranged from 1.85 (lower limit of normal [Quanjer]) to 2.88 (Global Initiative for Chronic Obstructive Lung Disease) cases/1,000/yr. Although about half of the cases had smoked less than 20 pack-years, smoking was the main risk factor for COPD, and it accounted for 29 to 39% of the new cases during the follow-up. Airway hyperresponsiveness was the second strongest risk factor (15-17% of new cases). Other determinants were respiratory infections in childhood and a family history of asthma, whereas the role of sex, age, and of being underweight largely depended on the definition of COPD used. CONCLUSIONS: COPD may start early in life. Smoking prevention should be given the highest priority to reduce COPD occurrence. Airway hyperresponsiveness, a family history of asthma, and respiratory infections in childhood are other important determinants of COPD. We suggest the need for a definition of COPD that is not exclusively based on spirometry.

Effect of fireworks events on urban background trace metal aerosol concentrations: is the cocktail worth the show?

We report on the effect of a major firework event on urban background atmospheric PM(2.5) chemistry, using 24-h data collected over 8 weeks at two sites in Girona, Spain. The firework pollution episode (Sant Joan fiesta on 23rd June 2008) measured in city centre parkland increased local background PM(2.5) concentrations as follows: Sr (x86), K (x26), Ba (x11), Co (x9), Pb (x7), Cu (x5), Zn (x4), Bi (x4), Mg (x4), Rb (x4), Sb (x3), P (x3), Ga (x2), Mn (x2), As (x2), Ti (x2) and SO(4)(2-) (x2). Marked increases in these elements were also measured outside the park as the pollution cloud drifted over the city centre, and levels of some metals remained elevated above background for days after the event as a reservoir of metalliferous dust persisted within the urban area. Transient high-PM pollution episodes are a proven health hazard, made worse in the case of firework combustion because many of the elements released are both toxic and finely respirable, and because displays commonly take place in an already polluted urban atmosphere.