28, but I don't understand why you ask? I know you are

, but if you are going to tell me you know how bad pollution was in the middle ages from personal experience, I'd be quite surprised

I assume you asked because I think pollution was worse back than as it was (in your view), right?
Curiosity mainly. I figured you were younger and had a degree of some kind. But also was interested in what your parents and grandparents in particular might have told you about pollution in their time.
The timeframe I mentioned here in the USA was a period of ramping up of industry that cause a similar ramp up in pollution. But that pollution was not every where. Mainly in the Big cities that had major industries. Especially the industries for making iron and iron products and in turn the combustion engine. Pre WW1 this was in well defined areas of early industrialization, mainly NE USA. Elsewhere the water and air was clean. Then when WW2 came a knocking it escalated even more. The "sleeping giant" was awakened by Japan. And America's industrial might and expansion took off. So did pollution in those same areas. But again other parts of the nation were not suffering from these problems. Rivers ran clean, wild life thrived and the air was clean and crisp. By the time I was graduating from High School (1970). The automobile industry was pumping out automobiles by the millions. And Large metro areas all over America was starting to see the adverse effects of uncontrolled combustion. But still the vast majority of land in America was not under attack by direct pollution like the big cities were. How badly you were affected by pollution was relative to were you lived.
As for living in the Middle ages, some think I'm from that time period. But even then pollution was relative to where the large cities were. Europe was evidence of that back then. With 1,000s of ppl living in those big cities and when every morning the lady of the house would dump the chamber pot into the street that had no real gutters....well the consequences of doing that are marked in History. But the country side was not under the same malady. So it again was all relative to where you lived.
Now even earlier times around the Mediterranean the Greeks and Romans knew how to remove the waste from their cities. But somehow the Europeans just did not (for the most part) adopt these 2 example cultures means of sanitation. Yet the knowledge was still there from this earlier time.
So yes pollution modeling in the mod has to be a process of ramping so that by the time you the player hit the industrial Era you are facing stiff problems. But those same stiff problems don't belong at the beginning of the games early Eras. When Pollution was introduced it was under the assumption that Every hut or workshop that made Anything Had to pollute. And the penalties were

and

. But when AIAndy introduced the property system there became more than just the

and

. But the values assigned previously before the new system were never re-evaluated. That time has finally came to the Mod. Which I know you are aware of. Because now there are substantial Penalties coming into play for ignoring these Property systems.
Well this has taken me 35 minutes to type. And I'm starting to lose my focus, so I'm going to stop. (yes I'm a Terrible typist and it frustrates me very much cause it hinders me from being articulate enough to get a coherent point across most of the time)