I am looking for a web site or telephone numbers for agencies that
provide CURRENT, DAILY air quality information (specifically
Particulate Matter PM10 and or PM2.5) in various cities around the
world.  Most important is current data for Santiago, Chili; Buenos
Aires, Argentina; and Rio de Janeiro, Brazil, though a web site that
offered data or links to these and other international cities would be
most useful.  I’ve already found general information on the air
quality in the above cities, but really need current daily info.

Hello, jim751,
In Brazil, Rio de Janeiro Environment Agency - FEEMA - shows in the
web page called Air Quality Bulletin - Boletim de Qualidade do Ar -
which is in Portuguese, daily data that is updated at 3pm daily, with
a lot of information on air quality in the state and in the city of
Rio de Janeiro:
http://www.feema.rj.gov.br/boletim_qualidade_ar.asp
luntes