uni'wissen 01(3)-2011_ENG

searchers know the mineralogical composition of the dust particles, they can establish whether the dust particles are, for instance, from automo- bile exhaust fumes, street dust, or smoke from coal-fired power plants. Most people would be shocked about all of the occasions on which hu- mans are exposed to dust particles: “Christmas is the worst time of all,” says Gieré. “Burning candles in the living room let off an unbelievably high amount of particulate matter.” Other parti- cles have a long journey behind them: Even dust from the Sahara reaches Freiburg. Lung Cells and Dust Particles in Test Tubes However, the team is not only interested in what the particles are composed of. They are also studying what influence dust particles have on human health. “Astoundingly,” says the miner- alogist, “we still know only little about their impact on our health.” But this question is becoming more and more important, because industrialized countries produce and release many different kinds of particles every day and everyone who lives there breathes them in. The research proj- ect is focusing initially on synthetic particles, such as those from paint, automobile tires, and deodorant, because we have a certain amount of influence over the extent to which we exposure ourselves to these kinds of dust. The influence of natural particles, on the other hand, is difficult to minimize: Wearing a face mask while riding a ­bicycle or staying at home when dust from the Sahara reaches Freiburg might be prudent pre- cautionary measures, but it is impossible to avoid the natural particles completely. Gieré is thus also planning on studying the impact of these particles on human health in the future. In order to determine to what extent the parti- cles found in Freiburg’s air are detrimental to our health, the researchers produce individual types of particles in the laboratory in various sizes and concentrations. They then expose cultures from the human lung to them in test tubes. “We don’t want to expose the lung cells to all kinds of par- ticles at once, because we are trying to find out what effect particular particles have on the hu- man lung,” explains Gieré. Various tests reveal how the lung cells react: Do the dust particles have an effect on the cells or even on the genes? The researchers are using an electron micro- “Astoundingly, we still only know little about their impact on our health” Hard-edged particle under a scanning electron microscope: This particle of calcium sulfate crystals was captured in the air in Strasbourg, France. It was released through industrial combustion processes. 6 uni'wissen 03