Fossil fuels, allergies, and a host of other ills

摘要

Our defenses are under assault from a growing spectrum of challenges. For allergies and asthma, most research has focused on indoor pollutants, genetic predispositions, and socio/emo-tional factors. During the past decade, however, there has been an explosion of new work regarding outdoor sources of respiratory irritation and sensitization, and all these emerging issues are associated with the combustion of fossil fuels.In the past 3 decades, asthma rates have risen several fold throughout the developed and developing world. There are multiple drivers and some are additive; others are acting synergistically.Rising ragweed pollen is the leading edge. Repeated studies confirm that elevated CO_2 stimulates weeds to produce pollen disproportionately to the photosynthetically derived growth in their biomass. It seems weedy, opportunistic species that thrive better in disturbances profit most from CO_2, putting the excess carbon into their male, reproductive, territorially seeking parts. Poison ivy (Toxicodendron taxa) does extraordinarily well, growing in vine abundance and toxicity, the chemical within it, urushiol, becoming stronger, just as the pollen grains in ragweed become more allergenic (as demonstrated by electrophoresis).