Where does air pollution come from?

One of the most striking aspects of air pollution is how invisible yet pervasive its effects are. Unlike more immediate environmental disasters, air pollution slowly chips away at public health, reducing life expectancy and quality of life, often without dramatic headlines. The comparison to starvation as a "frailty multiplier" is an interesting one; pollution doesn’t always kill directly but makes people more susceptible to fatal conditions.

Regarding the reduction in SO₂ emissions from shipping fuel, I’d love to see more discussion on how international regulatory pressure (e.g., IMO 2020) managed to enforce compliance in an industry notorious for cost-cutting. Was it simply a case of the alternatives being feasible enough, or did global coordination and monitoring play a stronger role than usual?

The other striking aspect for me is how, as has often been the case, those most affected are the poorest.

Levels of asthma in London are highest among kids in the vacinity of the docks where cruise and container ships and moor. They sit there running their engines for power, churning out SO2 and other pollutants. These areas are some of the poorest in London.

The same was the case in industrial cities during the industrial revolution. The poor factory workers lived close to the factories, and their kids grew up breathing the smoke. The wealthy owners moved to the outer suburbs (often upwind) where the air was clear.

There was a bit of an uproar a few years back about how many premiership football players were using asthma medication, a higher rate than the general population. The implication being that they were using them as performance enhacning drugs. But if you take into account that they disproportionately come from poor inner-city areas (not all, but many more), the proportion with asthma looks much more in line with the background rate.

Urban air pollution is insidious. Unlike the dreadful smogs of previous generations that lead to things like the Clean Air Act and the banning of open fires in urban areas, today's is invisible, and so doesn't create the same political problems. In fact if you try to do anything about inner city pollution you can pretty much guarentee an angry pushback.

> those most affected are the poorest

Please pardon my pedantry but this is by definition what poor is : having less means to escape material woes. Rich people are the ones that can elect to live in healthy areas.

Yes, but if the air pollution we're talking about is invisible then why would the rich elect for less exposure? Some might look at air quality data, but I suspect what is really going on is they seek out quiet. Noise pollution is the thing people really hate and avoiding that will likely lead to getting better air quality too.