Researchers around the world have introduced several steps to cut down on outdoor air pollution and concomitantly improving public health. For instance, some of these efforts include the regulation of industrial emissions, the establishment of low emission zones and the subsidies for public transportation, as well as restrictions on the use of wood and coal for heating in private households.
The connection between these actions and improved air quality and health appear apparent, but it is indeed difficult to quantify their effects. According to Jacob Burns from the Institute for Medical Information Processing, Biometry and Epidemiology (IBE) at the LMU's Pettenkofer School of Public Health, it is quite a challenge to evaluate the introduction of a measure like the low emission zone.
Scientists have established the connection between the adverse effects of air pollution on public health to cardiovascular and respiratory diseases, among others. But it is less clear whether measures designed to improve outdoor air quality reduce the concentration of pollutants present, and mitigate their effects on public health.
Burns added that it is essential to remember how many factors influence both air quality and the relevant health conditions. Pointing out further, he explained that the levels of energy consumption in industry, transport, and domestic households all play a substantial role in air pollutant levels, as does the weather.
And concerning health, to cite one example, the risk of developing cardiovascular disease, is influenced not only by particulate matter and other pollutants we breathe in but also by numerous genetic physiological and social risk factors. Burns said that this instance illustrates how difficult it can be to attribute changes in air pollutant concentrations, numbers of individuals admitted to hospitals, or mortality rates to any single measure.
The investigators reflected these difficulties in the new review published in the Cochrane Library. Cochrane is a network of more than 13,000 researchers, whose primary aim is to improve the quality of the scientific knowledge base upon which policy decisions relevant to human health are based.
The lead author of the new research, Professor Eva Rehfuess, the leader of the research group from the IBE at the Pettenkofer School of Public Health, offered the first systematic review aiming to identify and critically appraise all studies that evaluate the impact of measures aiming to improve all quality.
The research considered 38 specific measures, ranging from those to reduce traffic, to the regulation of industrial emissions and opportunities for cleaner and more efficient household heating systems.
Researchers at the LMU make several specific recommendations in this study, in particular concerning the design of future studies in this area, but some of which also directed at policymakers.
Rehfuess concluded that at the moment, many studies are conducted retrospectively. Ideally, the evaluation could be incorporated into the planning and introduction of the measure.
