<prompt> Translate the following text to SwahiliIt is currently unknown whether there is a time lag -- a delay between changes in PM exposures and changes in mortality rates -- in the chronic PMmortality relationship.  <response>: Kwa sasa haijulikani kama kuna muda wa kuchelewa - kuchelewa kati ya mabadiliko katika mfiduo wa PM na mabadiliko katika viwango vya vifo - katika uhusiano wa PM ya muda mrefu na vifo. 