Northland health officials are urging motorists, homeowners and businesses to support a smokefree cars and homes campaign.
The campaign has been developed by the Health Promotion Agency (HPA) and is supported by district health boards around the country, including the Northland DHB.
NDHB smokefree adviser Bridget Rowse said more than 350 New Zealanders are estimated to die each year due to of exposure to second-hand smoke.
"Data from the 2013 Census shows 19.1 per cent of people in Northland aged 15 years and over smoke regularly and according to the ASH Year 10 survey 2012, 31.2 per cent of Northland's 14 and 15-year-olds have travelled in a car in the previous seven days with someone who was smoking," Ms Rowse said.
"Reducing exposure to second-hand smoke in cars and homes is one way we can really make a difference to preventing smoke-related illnesses and deaths.
"Children are particularly vulnerable to second-hand smoke due to their smaller lungs and lower body weight and often do not have the choice to move away from smoke."
She said second-hand smoke was the leading environmental cause of death in this country. There was no safe level of exposure to second-hand smoke and those who were exposed may suffer from many of the same diseases as regular smokers, Ms Rowse said.
"Children need to be protected from second-hand smoke as much as possible as it can cause middle ear infections, lower respiratory illnesses and sudden unexpected death in infancy (SUDI also known as SIDS or cot death)," she said.
Whangarei's bus stops were recently made smokefree.
Radio advertising began in December and television advertisements started to air from the weekend and will continue to February 3.
Useful tips on keeping your car and home smokefree are available at www.smokefree.org.nz/second-hand-smoke.
For help to quit smoking call 0800 778 778 to speak to a Quit Advisor or visit www.quit.org.nz.