[Association of air pollution caused by sulphur dioxide and total number of particles in suspension and daily mortality in the city of Madrid (1986-1992)].

OBJECTIVE

The aim of the study is to quantify the relationship between sulphur dioxide (SO2), total suspended particulate (TSP) and daily mortality in Madrid.

METHODS

Data were plotted to exhibit the functional relationship between SO2, TSO and mortality. Box-Jenkins prewhitening method was used to detect lags and weights from the transfer function. Multivariate ARIMA models were built to control for confounding variables (air temperature and influenza epidemics).

RESULTS

Graphic analysis suggested a logarithmic relationship between SO2 and mortality, and lineal relationship with TSP. No evidence of a threshold was found for each pollutant. Cross-correlation functions showed a statistically significant relationship between daily mortality caused by organic, cardiovascular and respiratory diseases and air pollution. The first lag was statistically significant for TSP and the third lag for SO2. Multivariate models gave a coefficient beta = 0.039 for TSP and beta = 1.04 for SO2 indicating a 6.6% increase in mortality for each 100 micrograms/m3 increase in TSP and a 2.2% for SO2.

CONCLUSIONS

The result suggest a causal relationship between daily mortality and air pollution in Madrid.