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 Gerry 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 hired by an HVAC company and became the best local contractor. 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 to help with indoor comfort. They all had additional air quality systems upon their father’s insistence. The reason he got into the home services business was so that he could ensure quality indoor air through HVAC units 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 who has Gerry as a family relation can comfortably replace an air filter. We have come to refer to it as a right of passage. Some of us can even handle HVAC maintenance Gerry will randomly call to ask when you did duct cleaning or just checked the ductwork in your home. The best part is that he visits 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.