Air pollution from cars kills 50,000 a year in the UK [0]. Apparently closer to 200,000 a year in the US.
But it's even worse than that. 1.24 million each year are killed directly by motorists.[1] There are more young people killed directly by motorists than malaria or aids.
And yet many people are happy to continue driving around.
It's not like this is unavoidable. Electric cars are here, we could move the pollution out of cities. We could design our cities to be safer for walking and cycling. We could invest in public transport and pass on the cost of some of the externalities of cars to motorists.
[0] http://www.theguardian.com/environment/2010/mar/22/air-pollu... [1] http://www.who.int/mediacentre/factsheets/fs358/en/
So just to be clear... you're complaining that the US has five times the population of the UK but four times the deaths from air pollution?
Your overall point is right, though, that mid-20th-century motorist pretty much behaved like an oblivious jerk for decades.
You're saying that had something to do with fear of lead poisoning?
They knew lead was a poison.
Even the Romans knew lead was a poison so it wasn't like asbestos where suddenly a realisation was made.
Yet everyone pretended it did not matter. Everyone did what everyone else did. Nobody thought to avoid driving past schools because they weren't sure about the ethics of covering kids in a cloud of lead (with NO2, CO, O3, PAH's and maybe some invisible micro particles thrown into the mix).