About 2,000 deaths a year: the drama of Madrid and Barcelona that nobody seems to see

Failure to comply with recommendations on air pollution, noise, heat and access to green spaces is associated with more than 1,000 annual deaths in Barcelona and more than 900 in Madrid.

View of Barcelona from Tibidabo.

A new study by the Barcelona Institute for Global Health (ISGlobal) estimates, for the first time, premature mortality and distribution by socioeconomic levels of multiple environmental exposures related to urban and transportation planning in both cities.

Currently, more than half of the world’s population lives in cities. In Spain, this trend is even more pronounced and 80% live in urban settings. Madrid and Barcelona are two of the most populated cities in Europe and those with the greatest socioeconomic inequalities among their inhabitants. In European cities such as Vienna, Bradford and Barcelona, ​​recent research shows that considerable premature mortality – between 8 and 20% – is associated with poor urban and transport planning.

The new study, published in the journal Environmental Researchit was proposed to estimate the impact of non-compliance with international recommendations in air pollution –fine particles (PM2.5) and nitrogen dioxide (NOtwo)–, heat, traffic noise and lack of green spaces in residents over 20 years of age in Barcelona and Madrid, cities with different urban planning. While Madrid is structured around a central nucleus where most of the economic activity is concentrated; Barcelona, ​​on the other hand, is considered a compact city with its economic weight divided into various neighbourhoods.

The research was carried out with a environmental inequities. The researchers set out to “identify the population groups that are most exposed and most vulnerable to the effects of poor urban and transportation planning,” he explains. Tamara IungmanISGlobal researcher and first author of the study.

Regarding the methodology, the tool ‘Assessment of the impact on health of urban and transport planning’ was applied. (UTOPHIA), which has been developed by a team from ISGlobal. “We compared current exposure levels to international recommendations and estimated the fraction of preventable premature deaths that could be prevented if we were to meet those recommendations,” says Iungman.

Attributable deaths

The conclusions showed that failure to comply with the WHO recommendations on air pollution, noise and access to green spaces, together with excess heat, are related to 1,037 premature deaths per year in Barcelona. The air pollution by fine particles is the exposure associated with higher premature mortality, accounting for 524 deaths per year (48% of all deaths), followed by lack of green spaces (227 deaths), the traffic noise exposure (124 deaths), the heat (112 deaths) and, finally, exposure to NOtwo (12 deaths).

As to Madridthe total number of deaths attributable to non-compliance with international recommendations is 902. The lack of green spaces is the exposure associated with higher premature mortality (337 deaths per year), followed by excess heat (244 deaths), exposure to air pollution by NOtwo (207 deaths) and by PM2.5 (173 deaths), and noise (148 deaths).

A previous ISGlobal study attributed 20% of premature mortality in Barcelona to poor urban and transport planning. “The lower values ​​obtained in this health impact assessment for Barcelona and Madrid –7.1% and 3.4%, respectively– may be due to the fact that physical activity was not included in this study, as well as to the reductions in harmful exposure levels in recent years, as well as the different methodology used to estimate mortality attributable to noise”, argues Iungman.

Differences between Barcelona and Madrid

With better urban and transportation planning, Barcelona would avoid almost twice as many deaths as Madrid: 72 versus 33 deaths per 100,000 inhabitants. “This difference can be explained in part because scientific evidence associates higher mortality with exposure to PM2.5, which is higher in Barcelona; Another explanation would be the greater density of traffic and population in Barcelona, ​​given that its area represents one sixth of that of Madrid”, he details. Natalie MuellerISGlobal researcher and study coordinator.

The City of Barcelona exceeded the recommendations of the World Health Organization (WHO) of PM2.5 with an annual average of 15 μg/m3while the levels of NOtwo they did meet the recommended values, with an annual average of 37 μg/m3. In Madrid, the annual levels established by the WHO both fine particles and NOtwo.

The main difference between the two cities is in air pollutants. The conclusions show higher levels of fine particles in Barcelona and NOtwo in Madrid, and a different spatial distribution –high levels of PM2.5 throughout Barcelona and higher levels of nitrogen dioxide in the center of the Spanish capital.

“While the main source of NO emissiontwo is the local motorized traffic, the fine particles have a greater capacity to disperse and are associated with other sources of combustion, in addition to the traffic. Nearby large industrial areas and the port could influence the high levels of fine particles in Barcelona”Mueller points out.

Regarding the green spaces, the vast majority of the population of Madrid and Barcelona –84% and 95%, respectively– does not have access to these natural environments, based on the WHO recommendation to live at a distance of 300 meters from a green space of more than half a hectare. This lack of generalized access shows that “for green spaces to have health benefits –in addition to mitigating other exposures such as noise and excess heat– we must consider not only their availability in the city, but their distribution so that and residents can access them on foot,” he says.

With regard to noise, 97% of the population of Madrid and 96% of the population of Barcelona were exposed to levels of traffic noise motorized vehicles higher than the WHO recommendations. “Both cities present a considerable burden of mortality attributable to traffic noise, which emphasizes the need to address and reduce it to improve the health of the population”, argues the researcher.

Although there are no specific recommendations for the excessive heat, in Barcelona, ​​the minimum mortality was calculated at 22.5°C and, in Madrid, at 21.5°C, and the impacts of a potential reduction of 1º were estimated. “The two cities had a similar attributable death rate and we found correlations between less green space and higher heat and noise levels,” adds Iungman.

environmental inequities

The results of the study show that poor urban and transport planning in Barcelona is related to higher mortality in areas with lower socioeconomic levels, while in Madrid, the attributable mortality burden varies according to exposure. Although air pollution, the lack of green spaces and excessive heat are a general problem in Barcelona, ​​the attributable mortality was higher in the most disadvantaged areas. Thus, the populations of the most disadvantaged areas had a mortality rate 1.26 times highercompared to less disadvantaged groups.

In Madrid, the most disadvantaged neighborhoods tended to have a higher exposure to PM2.5 and heat than the less disadvantaged neighbourhoods, while NOtwo and noise presented the inverse association. This is probably due to the fact that the population of lower socioeconomic status resides in more peripheral areas and close to industrial areas, where the cost of living is cheaper – and therefore they are more exposed to PM.2.5 and heat–, while the population of medium and medium high socioeconomic level reside in the urban center of Madrid, with greater traffic and exposure to NOtwo and traffic noise.

With respect to green areas, although the lack of access affected both people of low and medium socioeconomic status – since, respectively, they tend to live in the southern and southeastern outskirts, areas with more industry and commerce; and in the center of the city with a limited presence of green areas. However, in terms of attributable mortality, people living in the most disadvantaged areas were the ones who had more adverse health impacts related to the lack of natural spaces, probably due to greater vulnerability and worse general health status.

Mark Nieuwenhuijsen, one of the authors of the study and director of ISGlobal’s Urban Planning, Environment and Health Initiative, points out that “this analysis is in line with previous research that shows that people who live in more disadvantaged neighborhoods tend to be more exposed to to harmful environmental exposures, compared to those living in wealthier areas; although this inequity depends on the design characteristics of each city”.

Nieuwenhuijsen concludes that “this work shows the great impact of environmental exposures on premature mortality and highlights the importance of designing cities taking into account the impacts on health, valuing the specificities of each urban environment and prioritizing disadvantaged populations.” “Health impact assessments are a powerful tool to guide policy makers towards a healthy, sustainable and fair city for all its residents”, he highlights.

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