The council's environmental protection team is advising people to be particularly careful with smoke from garden bonfires, which can cause breathing difficulties for asthma sufferers, particularly in hot weather, and can make it unpleasant for others using their gardens.
Sean Suckling, acting principal environmental protection officer, City of York Council, said: "The best thing to do if you are being bothered by smoke from a BBQ or bonfire is to approach the person causing it and politely make them aware of it - in most cases they may not have realised that their smoke was affecting others. Where a regular problem exists there are laws which can help because it's actually an offence to emit smoke, fumes or gases which cause a nuisance.
"The problem is made worse in this hot weather as people have their windows open and are also spending more time outside."