Interacting effects of particulate pollution and cold temperature on cardiorespiratory mortality in Scotland

Abstract

Objectives: To determine whether the effect of black smoke on cardiorespiratory mortality is modified by cold temperatures. Methods: Poisson regression models were used to investigate the relationship between lagged black smoke concentration and daily mortality, and whether the effect of black smoke on mortality was modified by cold temperature for three Scottish cities from January 1981 to December 2001.Main results: For all-cause respiratory and noncardiorespiratory mortality, there was a significant association between mortality and lagged black smoke concentration. Generally the maximum black smoke effect occurred at lag 0, although these estimates were not statistically significant. A 10 mgm 23 increase in the daily mean black smoke concentration on any given day was associated with a 1.68% (95% CI 0.72 to 2.65) increase in all-cause mortality and a 0.43% (95% CI 20.97 to 1.86), 5.36% (95% CI 2.93 to 7.84) and 2.13% (95% CI 0.82 to 3.47) increase in cardiovascular, respiratory and noncardiorespiratory mortality, respectively, over the ensuing 30-day period. The effect of black smoke on mortality did not vary significantly between seasons (cool and warm periods). For all-cause, cardiovascular and non-cardiorespiratory mortality the inclusion of interaction terms did not improve the models, although for all-cause and noncardiorespiratory mortality there was a suggestion for interaction between temperature and recent black smoke exposure. Conclusions: The results of this study suggested a greater effect of black smoke on mortality at low temperatures. Since extremes of cold and particulate pollution may coexist, for example during temperature inversion, these results may have important public health implications.

Climate change, extreme weather events, air pollution and respiratory health in Europe

“…In Italy, an effect of PM10 on respiratory mortality was found only for temperatures above the 50th percentile compared to no effect on days with a temperature below the 50th percentile [55]. The study of CARDER et al [79], carried out in Scotland, instead found a positive interaction between cold temperatures and black smoke concentrations on respiratory mortality. Other European studies analysed total mortality; they were focused on specific heatwave episodes [64,[66][67][68][69] or on both warm and cold periods [70] and provided evidence of a significant interaction between high temperature and pollutants, mainly ozone.…”

“…among those most susceptible, has the consequence of a larger pool of susceptible people at risk of air pollution effects the following summer [70,124,127]. To explain the interaction between pollutant and low temperature [79], a hypothesised mechanism is that the cold-related impairment of respiratory mucociliary function may inhibit the clearance of pollutants [107,108].…”

“…In all these studies the potential interaction between air pollution health effects and high or low temperature was tested through interaction terms or by means of a stratified analysis in time-series and case-crossover analyses. Among studies carried out in a European country (table 2), three studies [55,76,79] analysed the synergistic effect on mortality for respiratory causes. In the UK study, the ozone effect on respiratory mortality during hot days corresponded to a rate ratio of 1.009, while the pollutant had no effect on ordinary days (rate ratio51.000), but the ozone-heat interaction was significant only in London and ozone-heat interactions were greatest in those aged ,75 years [76].…”

Posibilidades de mejora en los planes de prevención frente al exceso de temperaturas

“…Se debe tener en cuenta que determinadas situaciones meteorológicas relacionadas con los extre mos térmicos favorecen la presencia de estos contaminantes, sobre todo en las gran des urbes debido principalmente al trans porte y a las actividades industriales. Algu nos autores incluso se cuestionan si esto debe tener implicaciones en los estándares de calidad del aire, estableciendo medidas para disminuir la máxima concentración permitida cuando se prevén situaciones peligrosas 45 .…”

Interactions of Physical, Chemical, and Biological Weather Calling for an Integrated Approach to Assessment, Forecasting, and Communication of Air Quality

“…The combined effect of urban heat islands and heatwaves may also increase the risk for potential heat-related illness for the individuals living in the urban zone (Basara et al 2010). The possibility of interactions between cold temperature and air pollutants in terms of their effect on cardiorespiratory mortality and whether this relation varies according to season has been investigated (Roberts 2004;Carder et al 2008).…”