The excess deaths per year quoted for air pollution are not what they seem. It does not indicate a number of people who actually die. It's the total number of days the average person's life is shortened by multiplied out by the population size and life expectancy. So if breathing traffic fumes causes or worsens a range of conditions that remove 4 years from the average person's life, that increases the average death rate in the population. It does not mean thousands of otherwise healthy people drop dead each year because they got too close to an exhaust pipe.
One thing it does neglect though is reduced quality of health and life. While something may not kill someone, it's still not great if it increases the incidence asthma or non-fatal cancer.
I read the results of a study a few months ago that (for some reason) looked at tiny iron particles discovered in the brains of corpses. The source of the particles were identifiable based on their shape/form. Naturally occurring ones (representing the normal background amount) were outnumbered by something a hundred times the amount of ones that come from ICE engines. It's unknown what is the medical/health effects of having your brain riddled with iron particles, but it's unlikely to be good.
It's just another aspect of local air pollution whose real effect will probably only become known in the coming decades. NoX, hydrocarbons, SoX, micro-particulates (these are also from brakes and tyres).
One thing it does neglect though is reduced quality of health and life. While something may not kill someone, it's still not great if it increases the incidence asthma or non-fatal cancer.
I read the results of a study a few months ago that (for some reason) looked at tiny iron particles discovered in the brains of corpses. The source of the particles were identifiable based on their shape/form. Naturally occurring ones (representing the normal background amount) were outnumbered by something a hundred times the amount of ones that come from ICE engines. It's unknown what is the medical/health effects of having your brain riddled with iron particles, but it's unlikely to be good.
It's just another aspect of local air pollution whose real effect will probably only become known in the coming decades. NoX, hydrocarbons, SoX, micro-particulates (these are also from brakes and tyres).