Middlesbrough has levels of air pollution that, if breathed in over a year, is the equivalent to smoking 90 cigarettes.
New analysis of data by the British Heart Foundation (BHF) has shown Middlesbrough to have the highest average daily level of air pollution in the north east.
It means people living in the town have an increased risk of death that is on average equivalent to smoking 93 cigarettes a year.
That's closely followed by Stockton on Tees, Redcar and Cleveland, Hartlepool and South Tyneside.
Breathing in polluted air in Middlesbrough over a year is equivalent to smoking 93 cigarettes.
Stockton on Tees - 88 cigarettes a year
Redcar and Cleveland - 88 cigarettes a year
Hartlepool - 86 cigarettes a year
South Tyneside - 85 cigarettes a year
These figures come as the British Heart Foundation urges the next UK government to adopt tougher World Health Organisation (WHO) air pollution limits.
The UK currently subscribes to EU limits on levels of fine particulate matter called PM2.5, which are not as strict as those set by the WHO.
Fine particulate matter is the most dangerous kind of air pollution, which finds its way into the circulatory system when inhaled.
PM2.5 is shown to have a detrimental effect on heart health and worsen existing medical conditions.
It also increases the risk of heart attacks and strokes.
Air pollution is a major public health emergency, and over many years it has not been treated with the seriousness it deserves. Unless we take radical measures now to curb air pollution, in the future we will look back on this period of inaction with shame.
Mr West added: "As these figures show, the effect of air pollution on our heart and circulatory system is profound and we have no choice over the air we breath in the places we live.
"Legislation was passed over a decade ago to protect people from passive smoke, and similarly decisive action must be taken to protect people from air pollution."
The government has yet to comment on the analysis. Before the dissolution of Parliament for the General Election it had introduced the Environment Bill, which set out a commitment to binding targets for fine particulate matter although it did not commit to the WHO guidelines.