Estimating ambient air pollution mortality and disease burden and its economic cost in Barcelona.

BACKGROUND: The new WHO air quality guidelines indicate that the air pollution disease burden is greater than previously reported. We aimed to estimate the air pollution disease burden and its economic cost in Barcelona to inform local action. METHODS: We used a quantitative health impact assessment to estimate the non-accidental mortality and incidence of childhood asthma and lung cancer attributable to long-term air pollution exposure in the city of Barcelona (Spain) in 2018-2019. We used the population weighted mean of PM2.5 and NO2 assigned at the geocoded address during the study period and the 2021 WHO air quality guidelines as counterfactual scenario to estimate new annual cases attributable to each pollutant separately and combined. We estimated the social cost of attributable deaths and the health care cost of childhood asthma and lung cancer attributable cases. We also estimated attributable mortality by city district and the mortality avoidable by achieving the WHO air quality interim targets. RESULTS: Mean exposure was 17 µg/m3 for PM2.5 and 39 µg/m3 for NO2. Total combined air pollution attributable mortality was 13% (95%CI = 9%-17%), corresponding to 1,886 deaths (95%CI = 1,296-2,571) and a social cost of €1,292 million (95%CI = 888-1,762) annually. Fifty-one percent (95%CI = 21%-71%) and 17% (95%CI = 7%-29%) of new cases of childhood asthma and lung cancer were attributable to air pollution with a health care cost of €4.3 and €2.7 million, respectively. Achieving the first unmet WHO air quality interim targets for PM2.5 and for NO2 would avoid 410 deaths and €281 million annually. CONCLUSION: Air pollution in Barcelona represents a huge disease and economic burden, which is greater than previous estimates. Much stronger measures to reduce PM2.5 and NO2 levels are urgently needed. Until the WHO air quality guidelines are met in the city, achieving each WHO air quality interim targets would avoid hundreds of deaths each year.

Study Protocol for the Evaluation of the Health Effects of Superblocks in Barcelona: The "Salut Als Carrers" (Health in the Streets) Project.

Superblocks are currently being introduced in Barcelona to respond to the city's scarcity of green spaces and high levels of air pollution, traffic injuries, and sedentariness. The aim is to calm the streets by reducing the number of square meters dedicated to private vehicles and to reclaim part of this public space for people. Salut als Carrers (Health in the Streets) is a project to evaluate the potential environmental and health effects of the superblock model with an equity perspective in Barcelona. This study aims to explain the various interventions implemented in different neighborhoods in Barcelona and the methods that will be used to evaluate them in a quasi-experimental and health impact assessment (HIA) approaches. Given the complexity of the intervention evaluated, the project employs mixed methodologies. Quantitative methods include: (a) a pre-post health survey of 1200 people randomly selected from the municipal register asked about self-perceived health and quality of life, social support, mental health, mobility, physical activity, neighborhood characteristics, and housing; (b) pre-post environmental measurements, mainly of nitrogen dioxide (NO2), particulate matter of less than 10 µm (PM10), and particulate matter of less than 2.5 µm (PM2.5) and black carbon; (c) pre-post environmental walkability measures using the Microscale Audit of Pedestrian Streetscapes (MAPS) tool; (d) use of public space and physical activity levels using the System for Observing Play and Recreation in Communities (SOPARC), a validated observation tool; (e) pre-post traffic injury measures with a comparison group; and (f) the comparison and integration of pre-post assessment with previous HIAs and the improvement of future HIAs. Qualitative studies will be performed to analyze residents' perception of these effects by using: (a) various focus groups according to different participant characteristics who are more or less likely to use the superblocks; and (b) a guerrilla ethnography, which is a method that combines ethnographic observation and semi-structured interviews. This study, which evaluates the impact of an ambitious urban-renewal program on health, will help to assess the effectiveness of public policy in terms of health and health inequalities.