The first "real-life" study showed lung function was worse in patients who spent two hours on London's Oxford Street compared with nearby Hyde Park.
The results are published in the New England Journal of Medicine.
The first "real-life" study showed lung function was worse in patients who spent two hours on London's Oxford Street compared with nearby Hyde Park.
The results are published in the New England Journal of Medicine.
The government says the regulation is designed to "help kick start the market for zero-carbon homes, encourage microgeneration technologies, and raise public awareness of the benefits of living in zero-carbon homes".
Home buyers can save up to £15,000, but the building industry warns that not many are likely to benefit soon.