The aim was that the follow-on class would incorporate a higher level of air-defence, land attack, anti-submarine and anti-ship capabilities than the preceding class.
Diesel engines produce much higher levels of air pollutants than petrol-driven engines, although they produce less carbon dioxide.
Perhaps surprisingly car drivers can be exposed to higher levels of air pollution inside their vehicle than on the pavement, suggesting that walking or cycling could be healthier.
Three studies published last week found that people exposed to higher levels of air pollution have greater risks of stroke, heart attack or cognitive deterioration.
"This small study found that exposure to higher levels of air pollution made the blood more likely to clot.
Higher levels of air pollution did appear to be linked with onset of a heart attack lasting for six hours after exposure.
Lower IAP values correspond to higher levels of air pollution.
Higher levels of air pollution may be associated to the increase rates of female births.
Numerous studies have demonstrated that higher levels of air pollution are associated with increased cardiorespiratory mortality.
