So2 + h2o
Power stations emit sulpur dioxide that when mixed with moisture produces acid rain or sulphuric acid in your lungs.
Sounds a bit extreme but is only school boy chemistry in action
When you see the yellow haze avoid breathing it in
Just common sense really
There are many gases and chemicals that we cannot detect but if you can see it then "see and avoid" is a wise precaution.
PS if I am incorrect about emmissions from said Power Station then I would like and air sample to be taken to prove it on a high pressure day when the plume can be seen