<prompt> Translate the following text to EnglishKwa hivyo, kuna kutokuwa na uhakika mkubwa ikiwa tafiti 26 juu ya thamani ya maisha ya takwimu hutoa makadirio ya kutosha ya thamani ya maisha ya takwimu yaliyookolewa na kupunguza uchafuzi wa hewa.  <response>: There is considerable uncertainty as to whether the 26 studies on the value of a statistical life provide adequate estimates of the value of a statistical life saved by air pollution reduction. 