<prompt> Translate the following text to EnglishUchunguzi wa HEI unatoa uaminifu kwa masomo ya awali lakini pia uligundua unyeti usiotazamiwa kuhusu a ni uchafuzi gani unaofaa zaidi, b jukumu la elimu katika kuingilia uhusiano kati ya uchafuzi na vifo, na c ukubwa wa uhusiano kulingana na jinsi uhusiano wa nafasi ulivyoshughulikiwa.  <response>: The HEI re-examination lends credibility to the original studies but also found unexpected sensitivities concerning a which pollutants are most important, b the role of education in mediating the association between pollution and mortality, and c the magnitude of the association depending on how spatial correlation was handled. 