The Air Quality forecast for South America is now available on the World Air Quality Index project, in parnership with the Brazilian Centro de Previsão do Tempo e Estudos Climáticos (CPTEC). The forecast can be accessed freely accessed from cptec.inpe.br as well as forecast/ south-america/.
One of the minor issue with the system used by the CPTEC is the input sources which are only based on modelisation of biomass burning and anthropogenic (human made) pollution. To be even more complete, it would further benefit from taking input data from global sources: for instance from the sahara dust (which indeed crosses the antlantic). So, just like the accuracy study we did not the Asian Air Quality forecast from Sprintars, you can find below the forecast accurary analysis for BRAMS for 5 cities in South America.