Voting in the Big Smoke Debate - a poll of Londoners' attitudes to passive smoking - ends on Wednesday.
Many cities are considering public smoking bans
People living in the city have been asked whether more restrictions should be imposed in London's cafes, shopping centres, taxis, restaurants, pubs and stations.
The London Health Commission (LHC), which advises mayor Ken Livingstone, is running the debate, which it describes as one of the UK's biggest consultations on a public health issue.
It follows a Mori poll of 221 Londoners which found 71% were bothered by other people's smoke in enclosed public places.
Scotland, as well as the cities of Sheffield, Birmingham and Brighton, are also considering bringing in more restrictions.
Organisers say it is not about whether people should smoke, but where it should be allowed.
The results of the poll, which began on 28 October, will be given to Mr Livingstone and LHC members in January.
Mr Livingstone said: "I welcome the Big Smoke Debate because it gives Londoners a voice about a health issue which is important to their lives.
"I look forward to hearing what the public wants done about smoking in enclosed public places and to working in partnership with groups across the capital to increase Londoners' access to healthier, smoke-free venues."