how have the laws passed to reduce people's exposure to secondhand smoke has a positive impact on health?

Since smokers are not allowed to smoke within restaurants, office buildings, airports, schools, and many other places, far fewer people are being exposed to secondhand smoke. People with asthma and allergies to cigarette smoke are now able to breathe more easily as well. Children are no longer being exposed to secondhand smoke in spaces outside of their homes.

It has a positive impact on health because then people won’t be second hand smoking any more

Yes you do , which is cool