The HEI PAPA project has now produced its first published papers (44—47). In the cities of Hong Kong,
Wuhan, Shanghai (all China) and Bangkok, Thailand, PM10, SO2, NO2 and Ozone were all found to be associated
with day-to-day variations in mortality, with effect estimates being equal to or larger than those reported from North
America and Europe (47). In most analyses, there was little indication of a threshold concentration below which no
effects on mortality were seen. Effects were larger in economically more deprived cities (Wuhan and Bangkok)
which was attributed to populations being less able to protect themselves from high exposures. In Wuhan, there was
also a clear interaction between pollution and temperature, pollution effects being higher on high temperature days
(44). Within the Hong Kong population, effects were also shown to be larger for populations living in economically
more deprived areas (46).