Attributable Risk to Assess the Health Impact of Air Pollution: Advances, Controversies, State of the Art and Future Needs.

Despite the increased attention given to the health impact assessment of air pollution and to the strategies to control it in both scientific literature and concrete interventions, the results of the implementations, especially those involving traffic, have not always been satisfactory and there is still disagreement about the most appropriate interventions and the methods to assess their effectiveness. This state-of-the-art article reviews the recent interpretation of the concepts that concern the impact assessment, and compares old and new measurements of attributable risk and attributable fraction. It also summarizes the ongoing discussion about the designs and methods for assessing the air pollution impact with particular attention to improvements due to spatio-temporal analysis and other new approaches, such as studying short term effects in cohorts, and the still discussed methods of predicting the values of attributable risk (AR). Finally, the study presents the more recent analytic perspectives and the methods for directly assessing the effects of not yet implemented interventions on air quality and health, in accordance with the suggestion in the strategic plan 2020-2025 from the Health Effect Institute.

Analysis of Temporal Variability in the Short-term Effects of Ambient Air Pollutants on Nonaccidental Mortality in Rome, Italy (1998-2014).

OBJECTIVES: The association between short-term air pollution exposure and daily mortality has been widely investigated, but little is known about the temporal variability of the effect estimates. We examined the temporal relationship between exposure to particulate matter (PM) (PM10, PM2.5) and gases (NO2, SO2, and CO) with mortality in a large metropolitan area over the last 17 y. METHODS: Our analysis included 359,447 nonaccidental deaths among ≥35-y-old individuals in Rome, Italy, over the study period 1998­2014. We related daily concentrations to mortality counts with a time-series Poisson regression analysis adjusted for long-term trends, meteorology, and population dynamics. RESULTS: Annual average concentrations decreased over the study period for all pollutants (e.g., from 42.9 to 26.6 µg/m3 for PM10). Each pollutant was positively associated with mortality, with estimated percentage increases over the entire study period ranging from 0.19% (95% CI: 0.13, 0.26) for a 1-Mg/m3 increase in CO (0­1 d lag) to 3.03% (95% CI: 2.44, 3.63) for a 10-µg/m3 increase in NO2 (0­5 d lag). We did not observe clear temporal patterns in year- or period-specific effect estimates for any pollutant. For example, we estimated that a 10-µg/m3 increase in PM10 was associated with 1.16% (95% CI: 0.53, 1.79), 0.99% (95% CI: 0.23, 1.77), and 1.87% (95% CI: 1.00, 2.74) increases in mortality for the periods 2001­2005, 2006­2010, and 2011­2014, respectively, and corresponding estimates for a 10-µg/m3 increase in NO2 were 4.20% (95% CI: 3.15, 5.25), 1.78% (95% CI: 0.73, 2.85), and 3.32% (95% CI: 2.03, 4.63). CONCLUSIONS: Mean concentrations of air pollutants have decreased over the last two decades in Rome, but effect estimates for a fixed increment in each exposure were generally consistent. These findings suggest that there has been little or no change in the overall toxicity of the air pollution mixture over time. https://doi.org/10.1289/EHP19.

Association Between Short-term Exposure to Ultrafine Particles and Mortality in Eight European Urban Areas.

BACKGROUND: Epidemiologic evidence on the association between short-term exposure to ultrafine particles and mortality is weak, due to the lack of routine measurements of these particles and standardized multicenter studies. We investigated the relationship between ultrafine particles and particulate matter (PM) and daily mortality in eight European urban areas. METHODS: We collected daily data on nonaccidental and cardiorespiratory mortality, particle number concentrations (as proxy for ultrafine particle number concentration), fine and coarse PM, gases and meteorologic parameters in eight urban areas of Finland, Sweden, Denmark, Germany, Italy, Spain, and Greece, between 1999 and 2013. We applied city-specific time-series Poisson regression models and pooled them with random-effects meta-analysis. RESULTS: We estimated a weak, delayed association between particle number concentration and nonaccidental mortality, with mortality increasing by approximately 0.35% per 10,000 particles/cm increases in particle number concentration occurring 5 to 7 days before death. A similar pattern was found for cause-specific mortality. Estimates decreased after adjustment for fine particles (PM2.5) or nitrogen dioxide (NO2). The stronger association found between particle number concentration and mortality in the warmer season (1.14% increase) became null after adjustment for other pollutants. CONCLUSIONS: We found weak evidence of an association between daily ultrafine particles and mortality. Further studies are required with standardized protocols for ultrafine particle data collection in multiple European cities over extended study periods.

Association Between Short-Term Exposure to PM2.5 and PM10 and Mortality in Susceptible Subgroups: A Multisite Case-Crossover Analysis of Individual Effect Modifiers.

We performed a multisite study to evaluate demographic and clinical conditions as potential modifiers of the particulate matter (PM)-mortality association. We selected 228,619 natural deaths of elderly persons (ages ≥65 years) that occurred in 12 Italian cities during the period 2006-2010. Individual data on causes of death, age, sex, location of death, and preexisting chronic and acute conditions from the previous 5 years' hospitalizations were collected. City-specific conditional logistic regression models were applied within the case-crossover "time-stratified" framework, followed by random-effects meta-analysis. Particulate matter less than or equal to 2.5 µm in aerodynamic diameter (PM2.5) and particulate matter less than or equal to 10 µm in aerodynamic diameter (PM10) were positively associated with natural mortality (1.05% and 0.74% increases in mortality risk for increments of 10 µg/m3 and 14.4 µg/m3, respectively), with greater effects being seen among older people, those dying out-of-hospital or during the warm season, and those affected by 2 or more chronic diseases. Limited associations were found among persons with no previous hospital admissions. Diabetes (1.98%, 95% confidence interval (CI): 0.54, 3.44) and cardiac arrhythmia (1.65%, 95% CI: 0.37, 2.95) increased risk of PM2.5-related mortality, while heart conduction disorders increased risk of mortality related to both PM2.5 (4.22%, 95% CI: 0.15, 8.46) and PM10 (4.19%, 95% CI: 0.38, 8.14). Among acute conditions, recent hospital discharge for heart failure modified the PM10-mortality association. The study found increases in natural mortality from PM exposure among people with chronic morbidity; diabetes and cardiac disorders were the main susceptibility factors.

Does chronic exposure to high levels of nitrogen dioxide exacerbate the short-term effects of airborne particles?

BACKGROUND: Long-term exposure to air pollutants has been hypothesised as a factor in susceptibility to short-term exposure to particulate matter (PM), but results are not coherent. We studied the short-term effects of PM10 on mortality and assessed whether long-term exposure to nitrogen dioxide (NO2) modifies this association. METHODS: We used a case-crossover design to evaluate daily PM10-related mortality among 124 432 35+ year-old participants who died in Rome between 2001 and 2010 and maintained the same address for at least 5 years before death. Modification of PM10-related mortality by long-term NO2 exposure was determined by two-way interaction, while a three-way interaction was used to assess effect modification of high NO2 levels in population groups defined by sociodemographic position and pre-existing diseases. RESULTS: Mortality increased by 0.82% (0.23-1.41%) for each 10 µg/m3 increase in PM10. Mortality rose by 1.22% (0.17-2.38%) in participants exposed to NO2 levels ≥50 µg/m3 and by 0.69% (0.03-1.34%) in those exposed to levels <50 µg/m3 with no effect modification (p-interaction 0.378). A suggestion of effect modification was seen in 85+-year-olds (3.10%; p-interaction 0.043), as well as in those with a pre-existing arrhythmia (3.26%; p-interaction 0.014) and chronic obstructive pulmonary disease (3.52%; p-interaction 0.042). CONCLUSIONS: Long-term exposure to NO2 is not likely to induce susceptibility to short-term PM10 exposure in the overall population. However, an effect modification of NO2 is probable in the elderly and in those suffering from arrhythmias and chronic obstructive pulmonary disease.

Correction: How Reliable Are Current Data for Assessing the Actual Prevalence of Chronic Obstructive Pulmonary Disease?

[This corrects the article DOI: 10.1371/journal.pone.0149302.].

[Health effects of air pollution in Rome in December 2015]. / Inquinamento atmosferico ed effetti sulla salute a Roma nel mese di dicembre 2015.

BACKGROUND: in December 2015 Rome has been interested by a peculiar meteorological situation, with atmospheric stability, no rain and little wind. These factors, coupled with the high pollutant emissions typical of the winter pre-Christmas period (increased use of private cars and domestic heating), caused extreme peaks in air pollution concentrations persisting several weeks. OBJECTIVES: describing daily trends in PM10 over two months, November and December 2015, and their impact on the health of the population of Rome. DESIGN: we analysed PM10 time series in Rome for November and December 2015. We estimated the association between daily PM10 concentrations and daily counts of deaths for natural and cardiorespiratory causes, and urgent hospitalizations/emergency-room visits for cardiorespiratory diseases, by use of Poisson regression models adjusted for time trends, influenza epidemics, and meteorology. These risk estimates have been used to quantify attributable deaths/admissions/visits due to exceedances of daily PM10 concentrations above EU-defined limit values in Rome for the period 29 November-30 December 2015. SETTING AND PARTICIPANTS: Rome, November and December 2015; population resident in Rome and deceased or hospitalized/ admitted to emergency rooms in hospitals within the city. MAIN OUTCOME MEASURES: daily mortality for natural (0+ years), respiratory (0+) or cardiac (35+) causes; urgent (non-scheduled) hospitalizations or admissions to emergency room visits for respiratory (0+) or cardiac (35+) diseases. RESULTS: in December 2015, only three days (10th, 11th, and 26th December) had PM10 concentrations below the EU-limit value of 50 µg/m3. Over the 31 days under analysis (from 29 November to 29 December) we estimated 26 natural deaths attributable to PM10 concentrations above 50 µg/m3. Similarly, we estimated 20 and 30 attributable cases of cardiorespiratory hospitalizations and admissions to emergency room visits, respectively. CONCLUSIONS: monitoring and control of anthropogenic emissions are mandatory in order to minimize the adverse health effects of air pollution, especially during air pollution peaks.

How Reliable Are Current Data for Assessing the Actual Prevalence of Chronic Obstructive Pulmonary Disease?

BACKGROUND: Estimating COPD occurrence is perceived by the scientific community as a matter of increasing interest because of the worldwide diffusion of the disease. We aimed to estimate COPD prevalence by using administrative databases from a city in central Italy for 2002-2006, improving both the sensitivity and the reliability of the estimate. METHODS: Multiple sources were used, integrating the hospital discharge register (HDR), clinical charts, spirometry and the cause-specific mortality register (CMR) in a longitudinal algorithm, to reduce underestimation of COPD prevalence. Prevalence was also estimated on the basis of COPD cases confirmed through spirometry, to correct misclassification. Estimating such prevalence relied on using coefficients of validation, derived as the positive predictive value (PPV) for being an actual COPD case from clinical and spirometric data at the Institute of Clinical Physiology of the National Research Council. RESULTS: We found that sensitivity of COPD prevalence increased by 37%. The highest estimate (4.43 per 100 residents) was observed in the 5-year period, using a 3-year longitudinal approach and combined data from three sources. We found that 17% of COPD cases were misclassified. The above estimate of COPD prevalence decreased (3.66 per 100 residents) when coefficients of validation were applied. The PPV was 80% for the HDR, 82% for clinical diagnoses and 91% for the CMR. CONCLUSIONS: Adjusting the COPD prevalence for both underestimation and misclassification of the cases makes administrative data more reliable for epidemiological purposes.

Desert Dust Outbreaks in Southern Europe: Contribution to Daily PM10 Concentrations and Short-Term Associations with Mortality and Hospital Admissions.

BACKGROUND: Evidence on the association between short-term exposure to desert dust and health outcomes is controversial. OBJECTIVES: We aimed to estimate the short-term effects of particulate matter ≤ 10 µm (PM10) on mortality and hospital admissions in 13 Southern European cities, distinguishing between PM10 originating from the desert and from other sources. METHODS: We identified desert dust advection days in multiple Mediterranean areas for 2001-2010 by combining modeling tools, back-trajectories, and satellite data. For each advection day, we estimated PM10 concentrations originating from desert, and computed PM10 from other sources by difference. We fitted city-specific Poisson regression models to estimate the association between PM from different sources (desert and non-desert) and daily mortality and emergency hospitalizations. Finally, we pooled city-specific results in a random-effects meta-analysis. RESULTS: On average, 15% of days were affected by desert dust at ground level (desert PM10 > 0 µg/m3). Most episodes occurred in spring-summer, with increasing gradient of both frequency and intensity north-south and west-east of the Mediterranean basin. We found significant associations of both PM10 concentrations with mortality. Increases of 10 µg/m3 in non-desert and desert PM10 (lag 0-1 days) were associated with increases in natural mortality of 0.55% (95% CI: 0.24, 0.87%) and 0.65% (95% CI: 0.24, 1.06%), respectively. Similar associations were estimated for cardio-respiratory mortality and hospital admissions. CONCLUSIONS: PM10 originating from the desert was positively associated with mortality and hospitalizations in Southern Europe. Policy measures should aim at reducing population exposure to anthropogenic airborne particles even in areas with large contribution from desert dust advections. CITATION: Stafoggia M, Zauli-Sajani S, Pey J, Samoli E, Alessandrini E, Basagaña X, Cernigliaro A, Chiusolo M, Demaria M, Díaz J, Faustini A, Katsouyanni K, Kelessis AG, Linares C, Marchesi S, Medina S, Pandolfi P, Pérez N, Querol X, Randi G, Ranzi A, Tobias A, Forastiere F, MED-PARTICLES Study Group. 2016. Desert dust outbreaks in Southern Europe: contribution to daily PM10 concentrations and short-term associations with mortality and hospital admissions. Environ Health Perspect 124:413-419; http://dx.doi.org/10.1289/ehp.1409164.

Short-term effects of particulate matter on mortality during forest fires in Southern Europe: results of the MED-PARTICLES Project.

BACKGROUND: An association between occurrence of wildfires and mortality in the exposed population has been observed in several studies with controversial results for cause-specific mortality. In the Mediterranean area, forest fires usually occur during spring-summer, they overlap with Saharan outbreaks, are associated with increased temperature and their health effects are probably due to an increase in particulate matter. AIM AND METHODS: We analysed the effects of wildfires and particulate matter (PM10) on mortality in 10 southern European cities in Spain, France, Italy and Greece (2003-2010), using satellite data for exposure assessment and Poisson regression models, simulating a case-crossover approach. RESULTS: We found that smoky days were associated with increased cardiovascular mortality (lag 0-5, 6.29%, 95% CIs 1.00 to 11.85). When the effect of PM10 (per 10 µg/m(3)) was evaluated, there was an increase in natural mortality (0.49%), cardiovascular mortality (0.65%) and respiratory mortality (2.13%) on smoke-free days, but PM10-related mortality was higher on smoky days (natural mortality up to 1.10% and respiratory mortality up to 3.90%) with a suggestion of effect modification for cardiovascular mortality (3.42%, p value for effect modification 0.055), controlling for Saharan dust advections. CONCLUSIONS: Smoke is associated with increased cardiovascular mortality in urban residents, and PM10 on smoky days has a larger effect on cardiovascular and respiratory mortality than on other days.

Short-term effects of particulate matter constituents on daily hospitalizations and mortality in five South-European cities: results from the MED-PARTICLES project.

BACKGROUND: Few recent studies examined acute effects on health of individual chemical species in the particulate matter (PM) mixture, and most of them have been conducted in North America. Studies in Southern Europe are scarce. The aim of this study is to examine the relationship between particulate matter constituents and daily hospital admissions and mortality in five cities in Southern Europe. METHODS: The study included five cities in Southern Europe, three cities in Spain: Barcelona (2003-2010), Madrid (2007-2008) and Huelva (2003-2010); and two cities in Italy: Rome (2005-2007) and Bologna (2011-2013). A case-crossover design was used to link cardiovascular and respiratory hospital admissions and total, cardiovascular and respiratory mortality with a pre-defined list of 16 PM10 and PM2.5 constituents. Lags 0 to 2 were examined. City-specific results were combined by random-effects meta-analysis. RESULTS: Most of the elements studied, namely EC, SO4(2-), SiO2, Ca, Fe, Zn, Cu, Ti, Mn, V and Ni, showed increased percent changes in cardiovascular and/or respiratory hospitalizations, mainly at lags 0 and 1. The percent increase by one interquartile range (IQR) change ranged from 0.69% to 3.29%. After adjustment for total PM levels, only associations for Mn, Zn and Ni remained significant. For mortality, although positive associations were identified (Fe and Ti for total mortality; EC and Mg for cardiovascular mortality; and NO3(-) for respiratory mortality) the patterns were less clear. CONCLUSIONS: The associations found in this study reflect that several PM constituents, originating from different sources, may drive previously reported results between PM and hospital admissions in the Mediterranean area.

[Chronic obstructive pulmonary disease (COPD) prevalence in Brindisi Province (Southern Italy) for the years 2005-2009]. / Stima della prevalenza di broncopneumopatia cronica ostruttiva (BPCO) nella Provincia di Brindisi per gli anni 2005-2009.

OBJECTIVES: to estimate the prevalence of chronic obstructive pulmonary disease (COPD) in Brindisi Province (Southern Italy) during the period 2005-2009. DESIGN: longitudinal approach using electronic health data. SETTING AND PARTICIPANTS: prevalence of COPD cases where defined as: 35+ year-old residents in Brindisi Province discharged from hospital with a diagnosis of COPD, recorded in any of the diagnostic fields, during the period 2005-2009; residents discharged in the previous 4 years and still alive at the beginning of the year considered; residents who died of COPD without previous hospital admissions for the same disease. Diagnoses codes selected from discharge data and cause of mortality archive were 490-492, 494 and 496, of the International Classification of Diseases - IX Revision - Clinical Modification (ICD-9-CM). MAIN OUTCOME MEASURES: crude prevalence and age standardized prevalence (per 100 residents), with confidence intervals (95%CI), by gender. RESULTS: COPD prevalence rates did not change in Brindisi Province over the period of study and the rate was around 6.6%. Prevalence was higher in males and increased with age both among males and females. The rates were higher among the females resident in Brindisi town than those observed among females resident in the rest of the municipalities of the Province considered. Among males, prevalence rates were similar between males living in the selected areas. CONCLUSIONS: this study is the first to present COPD prevalence rates estimated for the Brindisi Province based on electronic health data. The results showed a higher COPD prevalence in Brindisi then in other Italian cities and spatial and temporal differences by gender among Brindisi and the rest of the municipalities considered. Results require additional investigations. In particular, the use of additional health data sources not considered in the present study might help in better explaining the differences observed.

Which specific causes of death are associated with short term exposure to fine and coarse particles in Southern Europe? Results from the MED-PARTICLES project.

We investigated the short-term effects of particles with aerodynamic diameter less than 2.5µm (PM2.5), between 2.5 and 10µm (PM2.5-10) and less than 10µm (PM10) on deaths from diabetes, cardiac and cerebrovascular causes, lower respiratory tract infections (LRTI) and chronic obstructive pulmonary disease (COPD) in 10 European Mediterranean metropolitan areas participating in the MED-PARTICLES project during 2001-2010. In the first stage of the analysis, data from each city were analyzed separately using Poisson regression models, whereas in the second stage, the city-specific air pollution estimates were combined to obtain overall estimates. We investigated the effects following immediate (lags 0-1), delayed (lags 2-5) and prolonged exposure (lags 0-5) and effect modification patterns by season. We evaluated the sensitivity of our results to co-pollutant exposures or city-specific model choice. We applied threshold models to investigate the pattern of selected associations. For a 10µg/m(3) increase in two days' PM2.5 exposure there was a 1.23% (95% confidence interval (95% CI): -1.63%, 4.17%) increase in diabetes deaths, while six days' exposure statistically significantly increased cardiac deaths by 1.33% (95% CI: 0.27, 2.40%), COPD deaths by 2.53% (95% CI: -0.01%, 5.14%) and LRTI deaths by 1.37% (95% CI: -1.94%, 4.78%). PM2.5 results were robust to co-pollutant adjustments and alternative modeling approaches. Stronger effects were observed in the warm season. Coarse particles displayed positive, even if not statistically significant, associations with mortality due to diabetes and cardiac causes that were more variable depending on exposure period, co-pollutant and seasonality adjustment. Our findings provide support for positive associations between PM2.5 and mortality due to diabetes, cardiac causes, COPD, and to a lesser degree to cerebrovascular causes, in the European Mediterranean region, which seem to drive the particles short-term health effects.

Nitrogen dioxide and mortality: review and meta-analysis of long-term studies.

Exposure to ambient nitrogen dioxide (NO2) has been linked to increased mortality in several epidemiological studies but the question remains of whether NO2 is directly responsible for the health effects or is only an indicator of other pollutants, including particulate matter. The aim of the present review was to provide pooled estimates of the long-term effects of NO2 on mortality, which are potentially useful for health impact assessment. We selected 23 papers, published from 2004 to 2013, evaluating the relationship between NO2 and mortality, also including an assessment of the effect of particulate matter exposure. A random-effects meta-analysis was carried out on 19 studies. The pooled effect on mortality was 1.04 (95% CI 1.02-1.06) with an increase of 10 µg · m(-3) in the annual NO2 concentration and 1.05 (95% CI 1.01-1.09) for particulate matter <2.5 µm in diameter (PM2.5) (10 µg · m(-3)). The effect on cardiovascular mortality was 1.13 (95% CI 1.09-1.18) for NO2 and 1.20 (95% CI 1.09-1.31) for PM2.5. The NO2 effect on respiratory mortality was 1.03 (95% CI 1.02-1.03) and 1.05 (95% CI 1.01-1.09) for PM2.5. Four bipollutant analyses with particulate matter and NO2 in the same models showed minimal changes in the effect estimates of NO2. There is evidence of a long-term effect of NO2 on mortality as great as that of PM2.5. An independent effect of NO2 emerged from multipollutant models.

[Environmental indicators in EpiAir2 project: air quality data for epidemiological surveillance]. / Indicatori ambientali nello studio EpiAir2: i dati di qualità dell'aria per la sorveglianza epidemiologica.

OBJECTIVE: construction of environmental indicators of air pollution suitable for epidemiological surveillance in 25 Italian cities for EpiAir2 project (2006-2010) and presentation of the results from a 10 years of surveillance system (2001-2010) in 10 Italian cities. DESIGN: data on particulate matter (PM10 and its fine fraction PM2.5), nitrogen dioxide (NO2), and ozone (O3), measured in the 2006-2010 calendar period, were collected. Meteorological data needed to estimate unbiased measures of the effect of pollutants are: temperature, relative humidity (estimated "apparent temperature"), and barometric pressure. In continuity with the previous EpiAir project, the same criteria for the selection of monitoring stations were applied and standard methods to estimate daily environmental indicators were used. Furthermore, it was checked the adequacy of the selected data to represent the population exposure. SETTING AND PARTICIPANTS: EpiAir2 project, relative to the period 2006-2010, involves the cities of Milano, Mestre-Venezia, Torino, Bologna, Firenze, Pisa, Roma, Taranto, Cagliari, and Palermo, already included in the previous study. The city of Treviso, Trieste, Padova, Rovigo, Piacenza, Parma, Ferrara, Reggio Emilia, Modena, Genova, Rimini, Ancona, Bari, Brindisi, and Napoli are added to the previous group. RESULTS: particulate matter concentrations have decreased in most cities during the study period, while concentrations of NO2 and ozone do not show a similar clear trend. The analysis of the trend showed annual mean values of PM10 higher than 40 µg/m(3) in some areas of the Po Valley, and annual mean values of NO2 higher than 40 µg/m(3) in the cities of Trieste, Milano, Padova, Torino, Modena, Bologna, Roma, and Napoli. CONCLUSION: the enlargement of the EpiAir project to 13 other cities has highlighted critical issues related to the different geographical areas under study. Results of EpiAir2 project point out the need of a monitoring system of air pollution concentrations in both urban and industrial sites, in order to obtain reliable estimates of exposure for resident populations and to evaluate the related time trend.

[Air pollution and mortality in twenty-five Italian cities: results of the EpiAir2 Project]. / Inquinamento atmosferico e mortalità in venticinque città italiane: risultati del progetto EpiAir2.

OBJECTIVES: this study aims at presenting the results from the Italian EpiaAir2 Project on the short-term effects of air pollution on adult population (35+ years old) in 25 Italian cities. DESIGN: the short-term effects of air pollution on resident people died in their city were analysed adopting the time series approach. The association between increases in 10µg/m(3) in PM10, PM2.5, NO2 and O3 air concentration and natural, cardiac, cerebrovascular and respiratory mortality was studied. City-specific Poisson models were fitted to estimate the association of daily concentrations of pollutants with daily counts of deaths. The analysis took into account temporal and meteorological factors to control for potential confounding effect. Pooled estimates have been derived from random effects meta-analysis, evaluating the presence of heterogeneity in the city specific results. SETTING AND PARTICIPANTS: it was analysed 422,723 deaths in the 25 cities of the project among people aged 35 years or more, resident in each city during the period 2006-2010. MAIN OUTCOME MEASURES: daily counts of natural, cardiac, cerebrovascular, and respiratory mortality, obtained from the registries of each city. Demographic information were obtained by record linkage procedure with the civil registry of each city. RESULTS: mean number of deaths for natural causes ranged from 513 in Rovigo to 20,959 in Rome. About 25% of deaths are due to cardiac diseases, 10% to cerebrovascular diseases, and 7% to respiratory diseases. It was found an immediate effect of PM10 on natural mortality (0.51%; 95%CI 0.16-0.86; lag 0-1). More relevant and prolonged effects (lag 0-5) have been found for PM2.5 (0.78%; 95%CI 0.12-1.46) and NO2 (1.10%; 95%CI 0.63-1.58). Increases in cardiac mortality are associated with PM10 (0.93%; 95%CI 0.16-1.70) and PM2.5 (1.25%; 95%CI 0.17-2.34), while for respiratory mortality exposure to NO2 has an important role (1.67%; 95%CI 0.23-3.13; lag 2-5), as well as PM10 (1.41%; 95%CI - 0.23;+3.08). Results are strongly homogeneous among cities, except for respiratory mortality. No effect has been found for cerebrovascular mortality and weak evidence of association has been observed between ozone and mortality. CONCLUSIONS: a clear increase in mortality associated to air pollutants was observed. More important are the effects of NO2 (on natural mortality), mostly associated with traffic emissions, and of PM2.5 (on cardiac and respiratory mortality). Nitrogen dioxide shows an independent effect from the particulate matter, as observed in the bi-pollutant models.

Short-term associations between fine and coarse particulate matter and hospitalizations in Southern Europe: results from the MED-PARTICLES project.

BACKGROUND: Evidence on the short-term effects of fine and coarse particles on morbidity in Europe is scarce and inconsistent. OBJECTIVES: We aimed to estimate the association between daily concentrations of fine and coarse particles with hospitalizations for cardiovascular and respiratory conditions in eight Southern European cities, within the MED-PARTICLES project. METHODS: City-specific Poisson models were fitted to estimate associations of daily concentrations of particulate matter with aerodynamic diameter ≤ 2.5 µm (PM2.5), ≤ 10 µm (PM10), and their difference (PM2.5-10) with daily counts of emergency hospitalizations for cardiovascular and respiratory diseases. We derived pooled estimates from random-effects meta-analysis and evaluated the robustness of results to co-pollutant exposure adjustment and model specification. Pooled concentration-response curves were estimated using a meta-smoothing approach. RESULTS: We found significant associations between all PM fractions and cardiovascular admissions. Increases of 10 µg/m3 in PM2.5, 6.3 µg/m3 in PM2.5-10, and 14.4 µg/m3 in PM10 (lag 0-1 days) were associated with increases in cardiovascular admissions of 0.51% (95% CI: 0.12, 0.90%), 0.46% (95% CI: 0.10, 0.82%), and 0.53% (95% CI: 0.06, 1.00%), respectively. Stronger associations were estimated for respiratory hospitalizations, ranging from 1.15% (95% CI: 0.21, 2.11%) for PM10 to 1.36% (95% CI: 0.23, 2.49) for PM2.5 (lag 0-5 days). CONCLUSIONS: PM2.5 and PM2.5-10 were positively associated with cardiovascular and respiratory admissions in eight Mediterranean cities. Information on the short-term effects of different PM fractions on morbidity in Southern Europe will be useful to inform European policies on air quality standards.

Saharan dust and the association between particulate matter and daily hospitalisations in Rome, Italy.

INTRODUCTION: Outbreaks of Saharan dust have been shown to exacerbate the effect of particulate matter (PM) on mortality. Their role on PM-morbidity association is less clear. This study aims to evaluate the effect of Saharan dust on the PM-hospitalisations association in Rome, Italy. METHODS: We studied residents hospitalised in Rome between 2001 and 2004 and performed a time-series analysis to explore the effects of PM2.5, PM2.5-10 and PM10 on cardiac, cerebrovascular and respiratory emergency hospitalisations, respectively. Saharan dust days were identified by combining Light Detection and Ranging observations and analyses from operational models. We tested a dust-PM interaction to evaluate the hypothesis that the PM effect on hospitalisations would be enhanced on dust days. RESULTS: We studied 77 354, 26 557 and 31 620 hospitalisations for cardiac, cerebrovascular and respiratory diseases, respectively, providing effect estimates per IQR. PM2.5-10 was associated with cardiac diseases (3.93%; 95% CI 1.58 to 6.34). PM10 was associated with cardiac (3.37%; 95% CI 1.11 to 5.68), cerebrovascular (2.64%; 95% CI 0.06 to 5.29) and respiratory diseases (3.59%: 95% CI 0.18 to 7.12). No effect of PM2.5 was detected. Saharan dust modified the effect of the PM2.5-10 on respiratory hospitalisations, higher during dust days compared with dust-free days (14.63% vs -0.32%; p value of interaction=0.006). Saharan dust also increased the effect of PM10 on cerebrovascular diseases (5.04% vs 0.90%, p value of interaction=0.143). DISCUSSION: A clear enhanced effect of PM2.5-10 on respiratory diseases and of PM10 on cerebrovascular diseases emerged during Saharan dust outbreaks.

Air pollution and multiple acute respiratory outcomes.

Short-term effects of air pollutants on respiratory mortality and morbidity have been consistently reported but usually studied separately. To more completely assess air pollution effects, we studied hospitalisations for respiratory diseases together with out-of-hospital respiratory deaths. A time-stratified case-crossover study was carried out in six Italian cities from 2001 to 2005. Daily particulate matter (particles with a 50% cut-off aerodynamic diameter of 10 µm (PM10)) and nitrogen dioxide (NO2) associations with hospitalisations for respiratory diseases (n = 100 690), chronic obstructive pulmonary disease (COPD) (n = 38 577), lower respiratory tract infections (LRTI) among COPD patients (n = 9886) and out-of-hospital respiratory deaths (n = 5490) were estimated for residents aged ≥35 years. For an increase of 10 µg·m(-3) in PM10, we found an immediate 0.59% (lag 0-1 days) increase in hospitalisations for respiratory diseases and a 0.67% increase for COPD; the 1.91% increase in LRTI hospitalisations lasted longer (lag 0-3 days) and the 3.95% increase in respiratory mortality lasted 6 days. Effects of NO2 were stronger and lasted longer (lag 0-5 days). Age, sex and previous ischaemic heart disease acted as effect modifiers for different outcomes. Analysing multiple rather than single respiratory events shows stronger air pollution effects. The temporal relationship between the pollutant increases and hospitalisations or mortality for respiratory diseases differs.