Moderate smoking isn’t sinful, some saints smoked. Here’s what the Church says.

Question
Is smoking sinful?
Answer:
The Church does not consider smoking sinful. However, states that the abuse (overuse) of tobacco is forbidden since this could harm one’s health and is against the virtue of temperance.
What the Church focuses on is moderation in the enjoyment of beverages and licit bodily pleasures.
“The virtue of temperance disposes us to avoid every kind of excess: the abuse of food, alcohol, tobacco, or medicine. Those incur grave guilt who, by drunkenness or a love of speed, endanger their own and others’ safety on the road, at sea, or in the air”
St Josemaria Escriva smoked, and is said to have encouraged some of his first priests to smoke so they can reach out more to the laymen they were ministering to. Also, St John XXIII, Blessed Pius IX also smoked. We must abandon that puritanical attitude some of us have towards smoking. I don’t smoke, and had this issue growing up. Virtually everyone in my community then considered smoking as intrinsically evil. However, when i studied, i saw the Church’s position on it. It changed my mind however, many people still say “the Church is wrong there, it is sinful”. So, what i tell people is:
Obey the Church, listen to your conscience in matters concerning your own conduct. But, do not apply the same standard to everyone you meet. NEVER judge anyone.
We also have to take the health danger of heavy smoking seriously. We have learned a lot today about the effect of smoking. So if you are not a smoker, no need to begin. However, if you are a smoker, be moderate.
I believe that we are in the state of sin when we don’t avail ourselves of the Holy Spirit and its moderation. The fruit of the Spirit describes the elements of this moderation (Galatians 5:22-23). Temperance or self-control is one of the elements. This fruit contains our inner peace and strength. Casting all of our care on the Lord and being anxious for nothing are the best ways that I found to interact with the Holy Spirit (see 1Peter 5:5-7 and Philippians 4:5-7).