Pol Cosentino

Commuting, Air Quality and Welfare 

Abstract: We study the welfare effects of public transport infrastructure investments in the Paris region, highlighting the role of local air quality improvements typically omitted by standard quantitative urban models (QUMs). We first provide reduced-form evidence that tramway expansions improve local air quality. We then develop a QUM with endogenous worker and firm location choice, transport mode choice, and local air pollution affecting amenities and productivity. Applying the model to the Grand Paris Express metro project, we find welfare gains of around 1.5%. We show that omitting the air quality channel leads to a severe underestimation of welfare gains and spatial skill sorting, given the substantial heterogeneity in pollution exposure and its valuation across skill groups.

with Pascale Champalaune

[Paper]

Best paper from young researcher, Prix AFET - Fabrique de la Cité

Trade, Commuting and City Structure 

Abstract: Cities are places where people commute to work and where goods are traded across space. While a large literature examines how lower commuting costs reshape cities, much less is known about within-city trade costs as a distinct force. This paper studies both channels using the construction of the Petite Ceinture railroad in nineteenth-century Paris, the world's first circular transit system, designed for both freight and passengers. Using newly digitized data on firms, population, rents, and transport networks spanning 1801 to 1906, I provide causal evidence that improved access to the railroad reshaped the spatial distribution of economic activities during this period. To quantify general equilibrium effects, I develop and calibrate a quantitative urban model in which within-city freight costs generate spatial variation in tradable goods prices, creating consumption-driven forces at the residence absent from canonical models. Counterfactuals show that removing the railroad would substantially reduce total population, consumption of tradables, and spatial specialization. Ignoring within-city freight costs leads to a 17.1% underestimation of the effects of transport infrastructure on urban structure and welfare.

[CESifo WP] [Online Appendix]

Optimal Urban Transport Design in a Quantitative Spatial Model 

Abstract: This paper investigates how an urban transport infrastructure should be designed to maximize workers' welfare while taking into account general equilibrium effects. To do so, I make the bridge between  seminal works in the quantitative urban model literature (Ahlfeldt et al. [2015], Heblich et al. [2020]) and a simulated annealing algorithm used by Kreindler et al. [2024]. The developed framework allows for several commuting modes, accounts for the heterogeneity of neighborhoods, and considers general equilibrium effects, as workers reallocate within the city following changes in commuting costs. I apply this framework to examine how the Parisian metro should have been planned at the beginning of the 20th century. Results provide evidence that strategic metro stations are located within the city center and are driven by locations with higher productivity. Comparative static experiments shed light on the crucial role of structural parameters and metro construction cost parameters.

Boulevards and Barricades: Does Urban Structure Shape Social Unrest? 

Abstract: This paper studies how urban structure shapes social unrest. We develop a model in which a government trades off the agglomeration benefits of concentrating workers against the revolutionary risk this concentration creates. We test the model using Haussmann's renovation of Paris (1853-1870), which occurred between the 1848 revolution and the 1871 Paris Commune. Using newly digitized geo-referenced data on barricades, arrests, and firms, we show that the renovation targeted vulnerabilities revealed in 1848 by widening streets where barricades had appeared, improving military access to Places of Power, and displacing factories toward the periphery. These changes reshaped the geography of the 1871 uprising.

with Stephan Heblich and Gabriel Loumeau

Racial Preferences and Local Public Goods 

Abstract: This paper studies whether local public goods, such as natural amenities, influence the racial sorting though a market effect and an exclusion effect. First, I use a neighbourhood database of the United States over the 1880-2010 period and exploit different level in natural amenities abundance combined with changes in anti-black attitudes. Reduced-form evidence suggests the existence of both market and exclusion effects of natural amenities influencing racial sorting. Second, I use 2010 LODES data to get informations on workplace and residence employment by race at a granular level and to quantify a heterogeneous agents quantitative spatial model on 16 of the largest CBSAs. Results show the existence of strong homophily preferences both for blacks and whites, and the proximity to natural amenities increase these racial preferences. Counterfactual exercise shows that removing whole racial preferences decreases on average the racial segregation by 12.6 percentage points.