What are the patterns of inequality in exposure to air pollution in France?

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Pascale Champalaune (APE Master)

Recent Public Health studies concluded that deprived neighbourhoods seem more exposed to air pollution in Marseille or Strasbourg, while the relationship appears to be reversed in Paris. In Lyon, middle-class neighbourhoods seem more polluted than others (1). Yet, little is known about inequality in exposure to air pollution at the national level, and the economic literature has remained fairly silent regarding the impact that local environmental policies may have on these disparities. Inequality in exposure to fine particulate matter (known as PM2.5, for 2.5 micrometres) is particularly worth investigating for two reasons. First, this pollutant is ubiquitous, as it is emitted through various sources, be it the tertiary and residential sectors (50% of emissions in 2017), industrial activities (23%), or traffic (17%) (2). Second, it is estimated to be responsible for 48,000 early deaths annually in mainland France (3). Due to this harmfulness, both the European Union and the World Health Organisation set PM2.5 annual concentration guidelines (respectively equal to 25 and 10 μg/m3).

In this Master’s Thesis, Pascale Champalaune combines measures of income and other neighbourhood characteristics with satellite-based pollution data to provide the first national-scale study of inequality in exposure to fine particulate matter in France. First, descriptive evidence shows that, at the national level, the relationship between PM2.5 exposure and income follows a U-shaped curve, which implies that the poorest and the richest are more exposed than a large middle class. This reflects the fact that both poorer and richer households often concentrate in city centres. However, at the city level, that is, comparing neighbourhoods within urban areas, only the poorest areas seem more polluted. In a next step, Champalaune exploits the yearly variation in pollution level and median income within each neighbourhood during the 2006-2016 period to further examine this relationship. She shows that a higher neighbourhood income is indeed associated with a lower exposure to fine particles. Moreover, for a given level of income, neighbourhoods that host a higher proportion of immigrants are more polluted. This may be explained by a self-selection phenomenon whereby poorer households and immigrants would sort into cheaper but more polluted neighbourhoods, or by a disproportionate siting of polluting economic activities in poorer areas.

Champalaune also shows that, at the national level, exposure to fine particles decreased from 14 μg/m3 in 2010 to 9.5 μg/m3 in 2016 – a 30% fall – and that initially less exposed neighbourhoods experienced larger improvements. Hence, despite a general drop in exposure to fine particles, its distribution is getting increasingly unequal. The author then investigates the role played by a new policy requirement in this evolution. Indeed, between 2012 and 2015, 20 large French urban areas revised their Plans de Protection de l’Atmosphère (PPA), so as to newly implement measures aimed at mitigating PM2.5 concentration. Champalaune exploits the fact that cities adopted their schemes in a staggered fashion to estimate the causal impact of this policy change on inequality in exposure to PM2.5. She estimates that on average, PPA revisions accounted for about one fifth of the 30% decrease in exposure, and that neighbourhoods whose income lay above the median received higher improvements. Moreover, air quality improved more in less polluted areas, while the effect likely was very heterogeneous in more polluted ones. This indicates that the policy change had regressive redistributive impacts, both in terms of initial exposure and initial income, which contributed to the unequal changes observed at the national level. These findings suggest that, in order to halt this trend, policies aimed at enhancing air quality likely require improved spatial targeting.

(1) Padilla, C. M., W. Kihal-Talantikite, V. M. Vieira, P. Rossello, G. Le Nir, D. Zmirou-Navier, and S. Deguen (2014). “Air quality and social deprivation in four French metropolitan areas - A localized spatio-temporal environmental inequality analysis.” Environmental Research, 134, pp. 315-324.
(2) Citepa (2019). Gaz à effet de serre et polluants atmosphériques: Bilan des émissions en France de 1990 à 2017. 450 p.
(3) Pascal, M., P. de Crouy Chanel, M. Corso, S. Medina, V. Wagner, S. Goria et al., (2016). Impacts de l’exposition chronique aux particules fines sur la mortalité en France continentale et analyse des gains en santé de plusieurs scénarios de réduction de la pollution atmosphérique. Santé publique France. 158 p.

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References

Master’s thesis title: Inequality in Exposure to Air Pollution in France: Measurement and Impact of a City-Level Public Policy

Under the direction of: Lucas Chancel (PSE, WIL) & Thomas Piketty (PSE, EHESS, WIL)

Available at: https://dumas.ccsd.cnrs.fr/MEM-PSE/dumas-03045169

Contact: pascale.champalaune at psemail.eu - Linkedin Profile

Photo credit: Sander van der Werf - shutterstock