Much has been made of the current UK Government’s failure to tackle air pollution, with the most recent headline being the eye-watering costs to the taxpayer for failed legal challenges.  However, air pollution doesn’t just carry a financial cost, it is known to kill around 40,000 people in the UK every year, with eight out of 10 of those deaths due to cardiovascular disease  – and recent research published in The Lancet highlights how dangerous even short-term exposure to these airborne chemicals can be. 
In this randomised, cross-over study, patients aged over 60 years with stable ischaemic heart disease or chronic obstructive pulmonary disease (COPD) who had been clinically stable for six months, were age-matched with healthy volunteers. They were randomly assigned to take part in a two-hour walk, either along Oxford Street or in Hyde Park, in London.
Patients were monitored for black carbon, particulate matter (PM), ultrafine particles and nitrogen dioxide. The concentration of these particles were higher in those who walked on Oxford Street than in Hyde Park. Those who walked through Hyde Park experienced health benefits, including increased lung function. However, in the people who walked on Oxford Street, those positive effects were negated by exposure to PM, ultrafine particles and nitrogen dioxide. 
Furthermore, those who walked on Oxford Street who had COPD experienced more respiratory symptoms such as coughing, wheeze and shortness of breath. Those with ischaemic heart disease had increased cough. 
Black carbon is caused by the incomplete combustion of biomass and fossil fuels. According to the European Environment Agency (EEA) PM contains many carcinogenic compounds, and is the most harmful to human health. 
In March 2018, 49 cross-party MPs challenged the UK Government over it’s lack of tangible action on tackling air pollution, describing the current state of affairs as a ‘national health emergency’.  In the meantime, as the research paper author’s state: “It is important to impose policies and measures that can reduce traffic pollution so that every individual can enjoy the health benefits of physical activity.”