The study by the World Health Organisation and the American Cancer Society shows the cost of smoking ("Smoking cost the world $2 trillion in 2012: Study"; Feb 1).

In fact, the actual cost may even be higher if second-hand smoking is included.

The cost is not only in healthcare, it also involves loss of man-hours in work and economic productivity, not to mention death and economic difficulties for the families concerned.

What is disturbing is the recent indication that third-hand smoke can also contribute to health problems.

Third-hand smoke refers to toxic residue that remains on surfaces in areas where people have smoked.

Smoking in rooms can continue to contribute to problems for those in the rooms long after the smoking has stopped.

The young and elderly are especially susceptible to exposure to third-hand smoking and it is estimated that the problem can persist for up to six months.

It is also alarming to see elderly grandparents sitting around children's playgrounds and smoking so closely to the children who are playing.

Another problem area is smoking in public toilets. It is still rampant and there seems to be no real attempt to enforce the law prohibiting smoking.

Individuals with lighted cigarettes in lifts are not uncommon, and even in parks, public places and bus stops, smoking seems to be taking place without much interference.

Second-hand smoke from pedestrians leaving a trail of smoke behind them and even smoke from passing cyclists and motorcyclists, and drivers with cigarettes in their hands resting on their car windows, are also not uncommon sights.

If we intend to cut down the cost and damage from smoking, second-hand smoke and third-hand smoke, there needs to be a more concerted effort from all quarters.

Quek Koh Choon (Dr)