Aerosol exposure versus aerosol cooling of climate: what is the total health outcome?
1Division of Nuclear Physics, Dept. of Physics, Lund University, Lund, Sweden
2Division of Global Health, IHCAR, Karolinska Institutet, Stockholm, Sweden
3Dept. of Environmental Health, Institute of Public Health, University of Copenhagen, Copenhagen, Denmark
Abstract. Particles, climate change, and health have thought-provoking interactions. Emission of aerosol particles is one of the largest environmental problems concerning human health. On the other hand, aerosol particles can have a cooling effect on climate and a reduction of those emissions may result in an increased temperature, which in turn may have negative health effects. The objective of this work was to investigate the "total health" effects of aerosol emissions, which include both exposure to particles and consequences of climate change initiated by particles. As a case study the "total health" effect from ship emissions were estimated by adding the number of deaths from aerosol emission exposure to the calculated number of lives saved from the cooling effect of the particles. The analysis indicated an annual mortality from ship emissions of 26 000 (minimum uncertainty range −5000 to 52 000), with 60 000 deaths from direct aerosol exposure and 34 000 lives saved by the cooling effect of particles. This is the first attempt to calculate the combined effect of particle emissions on health. We conclude that measures to reduce particulate air pollution will in some cases (black carbon) have win-win effects on health and climate, but for most particulates cause a shift from exposure-related health effects towards an increasing risk of health consequences from climate change. Thus, measures to reduce aerosol emissions have to be coupled with climate change mitigation actions to achieve a full health benefit on a global level.