Suppose that the dominant, true-breeding parent was accidently self-pollinated instead of crossed with the true-breeding recessive parent. How would this affect the phenotypes of the F1 and F2 generation?

it would lead to upper respiratory infections and pneumonia.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.