Coal mines existed plenty some years back.
Most people who worked in the mines had little to no choice when it came to air quality.
When they went home, their standards for indoor air quality were low. They could clean the soot off their skin but not the one in their lungs. My grandfather Gerald was very young when his father worked in the mines. He later died of a respiratory-related ailment. When my grandfather was old enough to work, he made sure he found work far from the mines. He later got into the HVAC business. Good indoor air quality was vital to him. My mother followed in his footsteps and became an HVAC professional. It became a family tradition that every household among his five children had a whole-home air purification system. They all had a smart HVAC with suitable air purification help and a different air purification system, all upon their father’s insistence. The reason he got into the home service business was so that he could ensure air purification through HVAC equipment in as many homes as he could. I also have an uncle who is an HVAC technician, and together with my mother, they took over the family business after my grandfather retired. Everybody with Gerald as a family relation can comfortably replace an air filter; we have come to refer to it as a right of passage. Gerald will randomly call to ask about the last time you had duct cleaning done in your home. The best part is that they visit all of us often, and we all fight about who will host him and his grandmother in our home. They say it’s a bad habit, but deep down, we know they love it.