Without discounting the risks such chemicals cause, I often wonder how general environment toxicity changes over time. Victorian England for example sounds awfu

Without discounting the risks such chemicals cause, I often wonder how general environment toxicity changes over time. Victorian England for example sounds awful, with soot from burning coal everywhere, lead being used for babies’ dummies (its soft and all), and general lack of appreciation of hygiene. Dangerous chemicals like mercury and lead were used all over the place because they were cheap, and I guess no one knew any better. When we are now concerned about those toxic chemicals, to what extent is that an absolute concern, and to what a relative one?