What was discovered?

Banning smoking in public places has cut the rate of heart attacks by as much as one third in Europe and North America.

Passive smoking, by breathing the smoke left in a room when someone else has smoked a cigarette, is also dangerous because the smoke lowers the levels of "good" cholesterol in the blood which protects against hardening and narrowing of the arteries (which can increase the risk of a heart attack).  Banning smoking has also helped reduce the harmful effects of passive smoking.

How was it discovered?

Statistical analyses of medical records indicate that the rate of heart attacks were reduced after the smoking bans were introduced... but finding out the molecular mechanism for HOW this happens is much more intriguing!

A detailed knowledge of the molecules found in cigarette smoke is needed, and the effects of direct or passive smoking on the circulatory system (heart and blood vessels) must be understood... this can take years of study!

Some molecules in cigarette smoke affect the heart beat.  Others change the levels of other chemicals in our blood, such as the "good" cholesterol being reduced.  Other molecules can damage the cells of the lungs and cause them to be destroyed, as in emphysema, or become cancerous.

Why is it important?

The speed at which the good effects of banning smoking in public places has improved the figures for heart attacks in Europe and North America shows how effective a law can be over molecules around us... so that the molecules in our bodies that protect our health can be allowed to do their job effectively!

Action:

Well, the 'Action' might better be described as "non-Action" for this topic... you've guessed it... rather than giving up smoking, don't even start!!!