Yng Nghymru, mae ansawdd aer gwael yn cyfrannu at leihad mewn disgwyliad oes sy'n cyfateb i rhwng 1,000 a 1,400 o farwolaethau y flwyddyn. Yn aml, mae'n cael effaith amlwg ar y rhai mwyaf agored i niwed, fel yr ifanc iawn neu'r oedrannus iawn, a'r rhai sydd â chyflyrau anadlol a chardiofasgwlaidd.
In Wales, poor air quality contributes to a reduced life expectancy equivalent to between 1,000 and 1,400 deaths each year – often having a pronounced impact on the most vulnerable, such as the very young or very old, and those with respiratory and cardiovascular conditions.