In this study, ecological analysis was used to assess the relationship betw
een ambient air pollution and human mortality. All the data on environmenta
l measures and related factors, population size and number of deaths were c
ollected for the city of Beijing, PR China and its eight districts for the
years 1980-1992. In this study the concentration of SO42- was selected as a
main indicator of environmental pollution for the following reasons: (i) S
O42- data are available to cover all urban and suburban areas in Beijing co
mpared with other air pollutants during the study period; (ii) SO42- levels
indicate the concentration of sulfide (include sulfate) and acid fog in th
e air, and they are significantly lower in cleaner districts than in others
; and (iii) analyses showed that SO42- levels are significantly correlated
with daily mean concentrations of sulfur dioxide and nitrogen oxide, annual
coal combustion, number of households using gas fuel, counts of motor vehi
cles and population density. Age-standardised mortality significant correla
tions were calculated using the Chinese population census data in 1990. Sta
tistically rates due to specific diseases were observed between SO42- conce
ntration and total mortality and mortality due to cardiovascular disease, m
alignant tumour and lung cancer (r > 0.50 in all cases). The correlations w
ere not only found between the current SO42- concentration and these mortal
ities, but also for SO42- levels measured up to 12 years prior to death, wh
ich may suggest long-term effects of air pollution. No significant correlat
ions were observed for mortality from respiratory diseases and cerebrovascu
lar diseases (r = 0.30-0.50). This study indicates that the concentration o
f SO42- in air is a useful air pollution indicator in the areas where coal
is used as the main source of energy. Areas with high levels of SO42- exper
ienced higher mortality due to a variety of chronic diseases. (C) 2000 Else
vier Science B.V. All rights reserved.