Dirty density: Air quality and the density of American cities

Urban Pollution: A Global Perspective

“…An interesting question in interpreting the findings is what mechanisms could be responsible for the observed relationship between density and pollution exposure (see also Borck and Schrauth, 2021;Carozzi and Roth, 2022). While a complete investigation is made difficult by the scarcity of available data at a worldwide scale, we nonetheless try to shed some light on these channels here.…”

“…The green hollow diamond is the coefficient for Germany (DEU), and the red hollow triangle the one for the United States (USA). These are highlighted in order to compare them with findings by Borck and Schrauth (2021) and Carozzi and Roth (2022) respectively. Outliers (2.5% highest and lowest coefficients) are excluded from the graphical representation.…”

“…39 All coefficients plotted come from regressions including control variables as presented in Table 4. The green hollow diamond and the red hollow triangle show the coefficients for Germany (DEU) and the US, in order to compare them to prior papers in the field (Carozzi and Roth, 2022;Borck and Schrauth, 2021). Both coefficients are somewhat smaller than the ones in those papers.…”

“…4 However, omitted variables and reverse causality are difficult to tackle in these settings. Among the few serious efforts to identify the causal effect of population density on pollution are Borck and Schrauth (2021) and Carozzi and Roth (2022). Borck and Schrauth (2021) use panel data from German districts, while Carozzi and Roth (2022) use cross-sectional data from US metropolitan areas.…”

“…Among the few serious efforts to identify the causal effect of population density on pollution are Borck and Schrauth (2021) and Carozzi and Roth (2022). Borck and Schrauth (2021) use panel data from German districts, while Carozzi and Roth (2022) use cross-sectional data from US metropolitan areas. Both papers instrument density with a variety of historical and geological instruments.…”