The government has unveiled the first advertising campaign to highlight the "invisible dangers" of passive smoking.
The advert, which runs in England from Monday, shows dark smoke curling around guests at a wedding to demonstrate 85% of smoke is invisible and odourless.
It comes after a New Year campaign showed smokers getting caught on a fish hook to highlight the addictive nature of the habit.
But smokers' groups said it was another attempt to stigmatise smokers.
The ad, which will run on TV, online, in the press and on posters, makes it clear that wafting away smoke does nothing to reduce the effect of passive smoking.
Research by the Scientific Committee on Tobacco and Health has shown that second-hand smoke increases the risk of lung cancer by 24% and heart disease by 25%.
A poll of 1,600 people last month found that 90% thought passive smoking was harmful, but over half would still smoke in a room where non-smokers were present.
Public Health Minister Caroline Flint said: "Smoking is harmful not just to smokers but to the people around them.
"What this new campaign brings home very clearly is the full impact of second-hand smoke."
And she urged people to give up smoking ahead of the ban coming into place in England in July, which will outlaw smoking in all enclosed public places, such as pubs, restaurants and shops.
Professor Martin Jarvis, an expert on tobacco dependence at the University College London, said: "Children are particularly affected by breathing the poisons in second-hand smoke because their bodies are still developing.
"Their bronchial tubes and lungs are smaller and immune systems less developed, making them more vulnerable to the toxins in the smoke."
Betty McBride, of the British Heart Foundation, said: "Let's hope this new campaign will give smokers that extra nudge to stub out cigarettes for good.
"In doing so, they will be protecting not only their own heart health, but also that of their friends and family."
But Simon Clark, director of the smokers' lobby group Forest, said: "There's a fine line between education and propaganda and once again the government has crossed the line.
"The implication that non-smokers are in serious danger from second-hand smoke is not borne out by the evidence.
"The smoking ban, and campaigns like this, are out of all proportion to what is a relatively minor health risk.
"This is yet another attempt to stigmatise smokers and turn non-smokers against them."