London property prices are infamous for having risen well above inflation in the past two decades. But, a new factor increasingly on buyers' minds could help push the cost of buying a house back down: pollution levels.
Mark Hayward, chief executive of the National Association of Estate Agents told CNBC via telephone that air quality is "something house buyers will now start to factor in" to their decisions. He cited the example of London's Hyde Park, which, despite being an area where property regularly sells for millions of pounds, is in fact a "highly polluted area on a main thoroughfare."
Henry Pryor, a property buying agent and market commentator, approximated that pollution could impact house prices by 15 percent nationwide. Hayward placed the figure slightly lower, at 10 percent.
As well as influencing prices, high pollution levels could "affect saleability" for estate agents, Hayward said.
Pryor suggested that a "big catalyst has been Sadiq Khan's efforts as mayor (of London)," to increase awareness of pollution. On several days last winter particulate levels in London exceeded those in Beijing, the Chinese capital infamous for its smog. In February, a study by the Chinese Center for Disease Control and Prevention found that European pollution was more likely to impact mortality rates than that in China.
There has been industry discussion of a traffic light system being implemented to warn potential home buyers of poor air quality. Pryor said that although this was "not on the government's agenda" currently, it could be in 10 years.
While the growth in use of electric cars could have the potential to lower pollution levels in urban environments, Hayward pointed out that "there would have to be massive uptake to make a difference."
But, Pryor suggested that the trend provided opportunity for property agents to capitalize on technology that informed customers of air quality, for example using apps that alerted used of pollution at street level.
Research by the World Health Organization published in April 2015 revealed that for its European area, the impact of pollution in 2010 had cost $1.6 trillion. This figure took into consideration approximately 600,000 premature deaths, as well as those suffering from pollution-related diseases.
Pryor said that he had "clients based abroad or who are looking to buy abroad, and they have exactly the same concerns."