[Carboxyhemoglobin levels of selected population segments in variously structured and polluted areas of North Rhine-Westphalia].

Abstract

Measurements of carboxyhemoglobin (COHb)-content from about 13,000 inhabitants of various sites in western North Rhine-Westphalia are presented. Analyses were part of surveys on the effects of air pollution conducted between 1975 and 1980 in five designated, polluted areas. Determinations were executed in the Medical Institute for Environmental Hygiene, Duesseldorf, on behalf of the Ministry of Labour, Health and Social Administration. Analysis of blood samples for CO-content was performed by gas chromatography. Carboxyhemoglobin levels were calculated by reference to the individual hemoglobin levels. Our surveys have been conducted during several years and included different seasons. Before 1977, fifty years old men were investigated. Until 1978, sixty years old men were studied. In 1979 and 1980, sixty years old women and ten years old children were additionally incorporated into the survey. Statistical analysis of data included variables which influence personal CO-burden such as smoking, and in the case of non-smokers indoor air exposure through passive smoking, use of gas facilities and heating in the flat, as well as occupational exposure. Besides, the influence of age, sex and location was considered. The average COHb-level of the populations under study was expressed as the median of the distribution. The distribution-free Mann-Whitney U-test served for assessment of differences between groups. As a further parameter, the percentage of the measurements greater than 2,5% COHb was chosen, because it was thought to be more relevant to risk populations, i.e. people suffering from Angina pectoris. As expected, tobacco smoking exerted the greatest influence on COHb-level. In non-smokers a trend, indicating a relationship between indoor air pollution and COHb-content could be observed. If high CO gas such as coke gas was used in flats with gas facilities COHb-levels were significantly raised. Surveys performed in 1979 and in 1980 showed a sex-dependent difference between median COHb saturations, women having lower values than men. The difference of these figures between adults and children is statistically significant. Comparisons between adult nonsmokers from various sites prompted a significant difference only in the case of the Oberbergischer Kreis (County), having the lowest median COHb-value. The highest COHb-levels by far were encountered in the city of Duisburg in January 1979, when very unfavourable meterological conditions (Smog alarm, degree 1) were present. The median COHb saturations reached on this occasion were very near to the limits considered to be critical for populations at special risk.