This is my problem with the studies on suburban sprawl is they do not factor in all of the things, they are generally only looking at one thing namely car and home pollution
Then you have Higher Crime, and a whole host of other matters that come with Dense Urban Centers that you do not get when people spread out.
On Balance I will take suburban sprawl over Urban Density every day, and twice on Sunday
Suburbanites are at very high risk of life-altering consequences from the actions of other humans. Many of those actions are crimes (DUI, distracted driving, reckless driving), but worse, some are not even crimes (incompetent driving, tired driving, intentional killing of annoying cyclists). That we feel so differently about these compared to more traditionally urban forms of crime is just cognitive bias with a helping of racism.
And with respect to density, produce for NYC was grown within sight of Manhattan as late as 1960. The impact of the belt of suburbia from Richmond, VA to New Hampshire is far more harmful that the cities.