@article{BorckPflueger2019,
  author    = {Borck, Rainald and Pfl{\"u}ger, Michael},
  title     = {Green cities? Urbanization, trade, and the environment},
  series = {Journal of regional science},
  volume    = {59},
  journal   = {Journal of regional science},
  number    = {4},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0022-4146},
  doi       = {10.1111/jors.12423},
  pages     = {743 -- 766},
  year      = {2019},
  abstract  = {Is urbanization good for the environment? This paper establishes a simple core-periphery model with monocentric cities, which comprises key forces that shape the structure and interrelation of cities to study the impact of the urban evolution on the environment. We focus on global warming and the potential of unfettered market forces to economize on emissions. The model parameters are chosen to match the dichotomy between average "large" and "small" cities in the urban geography of the United States, and the sectoral greenhouse gas emissions recorded for the United States. Based on numerical analyzes we find that a forced switch to a system with equally sized cities reduces total emissions. Second, any city driver which pronounces the asymmetry between the core and the periphery drives up emissions in the total city system, too, and the endogenous adjustment of the urban system accounts for the bulk of the change in emissions. Third, none of the city drivers gives rise to an urban environmental Kuznets curve according to our numerical simulations. Finally, the welfare-maximizing allocation tends to involve dispersion of cities and the more so the higher is the marginal damage from pollution.},
  language  = {en}
}
@article{BorckTabuchi2019,
  author    = {Borck, Rainald and Tabuchi, Takatoshi},
  title     = {Pollution and city size: can cities be too small?},
  series = {Journal of Economic Geography},
  volume    = {19},
  journal   = {Journal of Economic Geography},
  number    = {5},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {1468-2702},
  doi       = {10.1093/jeg/lby017},
  pages     = {995 -- 1020},
  year      = {2019},
  abstract  = {We study optimal and equilibrium sizes of cities in a city system model with pollution. Pollution is a function of population size. If pollution is local or per-capita pollution increases with population, equilibrium cities are too large under symmetry; with asymmetric cities, the largest cities are too large and the smallest too small. When pollution is global and per-capita pollution declines with city size, cities may be too small under symmetry; with asymmetric cities, the largest cities are too small and the smallest too large if the marginal damage of pollution is large enough. We calibrate the model to US cities and find that the largest cities may be undersized by 3-4\%.},
  language  = {en}
}
@techreport{BorckSchrauth2019,
  type      = {Working Paper},
  author    = {Borck, Rainald and Schrauth, Philipp},
  title     = {Population density and urban air quality},
  series = {CEPA Discussion Papers},
  journal   = {CEPA Discussion Papers},
  number    = {8},
  issn      = {2628-653X},
  doi       = {10.25932/publishup-42771},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427719},
  pages     = {53},
  year      = {2019},
  abstract  = {We use panel data from Germany to analyze the effect of population density on urban air pollution (nitrogen oxides, particulate matter and ozone). To address unobserved heterogeneity and omitted variables, we present long difference/fixed effects estimates and instrumental variables estimates, using historical population and soil quality as instruments. Our preferred estimates imply that a one-standard deviation increase in population density increases air pollution by 3-12\%.},
  language  = {en}
}
@article{Borck2019,
  author    = {Borck, Rainald},
  title     = {Public transport and urban pollution},
  series = {Regional science and urban economics},
  volume    = {77},
  journal   = {Regional science and urban economics},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0166-0462},
  doi       = {10.1016/j.regsciurbeco.2019.06.005},
  pages     = {356 -- 366},
  year      = {2019},
  abstract  = {This paper studies the effect of public transport policies on urban pollution. It uses a quantitative equilibrium model with residential choice and mode choice. Pollution comes from commuting and residential energy use. The model parameters are calibrated to replicate key variables for American metropolitan areas. In the counterfactual, I study how free public transport coupled with increasing transit speed affects the equilibrium. In the baseline simulation, total pollution falls by 0.4\%, as decreasing emissions from transport are partly offset by rising residential emissions. A second counterfactual compares a city with and without public transit. This large investment decreases pollution by 1.7\%. When jobs are decentralized, emissions fall by 0.5\% in the first and by 3\% in the second counterfactual.},
  language  = {en}
}