Respiratory health, effects of ambient air pollution and its modification by air humidity in Drobeta-Turnu Severin, Romania

Background: Associations between ambient air pollution and respiratory health have been mainly reported for Western Europe and Northern America. Objectives: Our goal was to investigate such associations among the population of Drobeta-Turnu Severin, Romania, a city in Central Eastern Europe (CEE), and to quantify their modification by air humidity. The latter is of increased interest for the current discussion about the potential effects of climate change on human health. Methods: We investigated (study period: 23.01.2001-31.08.2002) the associations between chronic obstructive pulmonary disease (COPD), asthma and chronic bronchitis (CB) and total suspended particles (TSP), sulphur dioxide (SO2) and nitrogen dioxide (NO2). Generalized additive models (GAM) controlling for time patterns and weather effects were applied. Delayed effects up to seven days were analysed in single lag and polynomial distributed lag models (PDLMs). Results: An increase of 10 mu g/m(3) TSP was related to a 3.3% (95% CI: 0.3%-6.4%) and a 2.8% (95% CI: 0.1 %-5.7%) increase for hospital admissions for chronic bronchitis with a lag of one and four days, respectively. The adverse effect of TSP on chronic bronchitis was reduced by higher humidity. An increase of 10 mu g/m(3) SO2 was related to a 6% (95% CI: 7%-25%) increase, with a two days lag, for hospital admissions for chronic bronchitis. We have not been able to identify a threshold, below which ambient TSP and SO2 concentrations have no effect on hospital admissions for chronic bronchitis. We found adverse but nonsignificant influences of TSP. SO2 and NO2 on total respiratory hospital admissions, COPD and asthma and NO2 on chronic bronchitis. Conclusions: We conclude that in Drobeta-Turnu Severin CB is associated with TSP and mainly SO2 Dry air aggravates the adverse effect of TSP. (C) 2009 Elsevier B.V. All rights reserved.