12 research outputs found
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The impact of European legislative and technology measures to reduce air pollutants on air quality, human health and climate
European air quality legislation has reduced emissions of air pollutants across Europe since the 1970s,
affecting air quality, human health and regional climate. We used a coupled composition-climate
model to simulate the impacts of European air quality legislation and technology measures
implemented between 1970 and 2010. We contrast simulations using two emission scenarios; one
with actual emissions in 2010 and the other with emissions that would have occurred in 2010 in the
absence of technological improvements and end-of-pipe treatment measures in the energy, industrial
and road transport sectors. European emissions of sulphur dioxide, black carbon (BC) and organic
carbon in 2010 are 53%, 59% and 32% lower respectively compared to emissions that would have
occurred in 2010 in the absence of legislative and technology measures. These emission reductions
decreased simulated European annual mean concentrations of fine particulate matter(PM2.5) by 35%,
sulphate by 44%, BC by 56% and particulate organic matter by 23%. The reduction in PM2.5
concentrations is calculated to have prevented 80 000 (37 000â116 000, at 95% confidence intervals)
premature deaths annually across the European Union, resulting in a perceived financial benefit to
society of US$232 billion annually (1.4% of 2010 EU GDP). The reduction in aerosol concentrations
due to legislative and technology measures caused a positive change in the aerosol radiative effect at
the top of atmosphere, reduced atmospheric absorption and also increased the amount of solar
radiation incident at the surface over Europe. We used an energy budget approximation to estimate
that these changes in the radiative balance have increased European annual mean surface temperatures
and precipitation by 0.45 ± 0.11 °C and by 13 ± 0.8 mm yrâ1 respectively. Our results show that the
implementation of European legislation and technological improvements to reduce the emission of
air pollutants has improved air quality and human health over Europe, as well as having an unintended
impact on the regional radiative balance and climate
The global distribution of ammonia emissions from seabird colonies
Seabird colonies represent a significant source of atmospheric ammonia (NH3) in remote maritime systems, producing a source of nitrogen that may encourage plant growth, alter terrestrial plant community composition and affect the surrounding marine ecosystem. To investigate seabird NH3 emissions on a global scale, we developed a contemporary seabird database including a total seabird population of 261 million breeding pairs. We used this in conjunction with a bioenergetics model to estimate the mass of nitrogen excreted by all seabirds at each breeding colony. The results combined with the findings of mid-latitude field studies of volatilization rates estimate the global distribution of NH3 emissions from seabird colonies on an annual basis. The largest uncertainty in our emission estimate concerns the potential temperature dependence of NH3 emission. To investigate this we calculated and compared temperature independent emission estimates with a maximum feasible temperature dependent emission, based on the thermodynamic dissociation and solubility equilibria. Using the temperature independent approach, we estimate global NH3 emissions from seabird colonies at 404 Gg NH3 per year. By comparison, since most seabirds are located in relatively cold circumpolar locations, the thermodynamically dependent estimate is 136 Gg NH3 per year. Actual global emissions are expected to be within these bounds, as other factors, such as non-linear interactions with water availability and surface infiltration, moderate the theoretical temperature response. Combining sources of error from temperature (±49%), seabird population estimates (±36%), variation in diet composition (±23%) and non-breeder attendance (±13%), gives a mid estimate with an overall uncertainty range of NH3 emission from seabird colonies of 270 [97â442] Gg NH3 per year. These emissions are environmentally relevant as they primarily occur as âhot-spotsâ in otherwise pristine environments with low anthropogenic emissions