Yes, you can definitely get these effects although it may not be truly global.
Rising CO2 would have implications for global warming but is not directly life threatening at the sort of concentrations we are talking about.
Sulfer, particulates, carbon monoxide, lead (before we phased it out of petrol) and many more though are dangerous and are already rising to toxic levels in some areas.
Particularly in China and areas burning dirty coal this can get seriously bad already.
One way this could happen is if the corporate powers managed to sidestep oversight and neutralize or shut down anti-pollution laws. They could then run their factories and generators as dirty as they liked, while rich people live in isolated islands or air conditioned and filtered areas far away from the consequences.
Even now this is already starting to happen, for example in Hong Kong:
The mortality rate from vehicular pollution can be twice as high near heavily travelled roads, based on a study conducted in the Netherlands at residences 50 metres from a main road and 100 metres from a freeway. Since millions of people in Hong Kong live and work in close proximity to busy roads, this presents a major health risk to city residents. The Hong Kong Medical Association estimates that air pollution can exacerbate asthma, impair lung function and raise the risk of cardio-respiratory death by 2 to 3 percent for every increase of 10 micrograms per cubic metre of pollutants. Studies by local public health experts have found that these roadside pollution levels are responsible for 90,000 hospital admissions and 2,800 premature deaths every year.
And elsewhere in China:
Chinese scientists have warned that the country's toxic air pollution is now so bad that it resembles a nuclear winter, slowing photosynthesis in plants – and potentially wreaking havoc on the country's food supply.
Essentially all you need is for people to increase burning the dirtier kinds of fossil fuels (coal in particular) without sufficient safety in place and while increasing production and you don't need to extrapolate much beyond what we already have.
Keep in mind also that things don't need to be immediately harmful for people to wear masks. Asbestos can get in the lungs for a long time before you show symptoms, but people still wear breathing masks to work with it.
Now, these would still not be completely global, for example out at sea or a long way from industrial centers there would still be smog free areas - and as a result extremely expensive homes - but you could easily cover the vast majority of the available land areas, and certainly all major cities.