description
- Tropospheric ozone at the Earth's surface is a key pollutant, having numerous impacts including degradation in health, particularly in lung function and cardiovascular systems and reduced crop yields, particularly for wheat, maize and rice. In many regions of the world tropospheric ozone is decreasing, but East Asia has seen rapid growth in tropospheric ozone over the past two decades. Ozone production in the troposphere is fuelled by two precursors: nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight. The general increases in ozone seen regionally in Asia have been caused by large overall increases in these precursor emissions, particularly from China. Whilst the trends in ozone itself can be detected relatively straightforwardly, both at the surface and from satellites, tracking long-term changes in regional NOx and VOCs in the background atmosphere is much more technically challenging. The production of ozone occurs as pollution is lifted and transported over long distances, and the effects of emissions are trans-boundary, often impacting downwind countries as well as the original emitter. Recent VOC observations made by the University of York in China has shown that the mixture of VOCs and NOx being emitted from Chinese cities and industry is unusually skewed towards VOCs, and their control would, at this time, be a more effective policy tool than reductions in NOx. This collaborative project between the NCAS/University of York and the National Institute for Environmental Studies (NIES) will develop and deploy novel technologies for the autonomous measurement of volatile organic compounds (VOCs), key precursors to the surface air pollutant ozone. The instrumentation developed will be deployed at a unique Japanese research station (Hateruma Observatory) and the data generated used to identify and quantify the trans-boundary sources (both geographic and sectoral) of VOCs that are, in part, responsible for the significant recent upwards trends in Asian surface ozone. There are very few long-term measurements of VOCs, and what few measurements there are generally only cover a very limited range. Many critical compounds such as alcohols, aldehydes and ketones still go unmeasured in long-term programmes such as WMO GAW, as do higher molecular weight hydrocarbons, for example from fuel evaporation. The project will create a new technology, utilising advanced electronic cooling methods to collect and concentrate air arriving at the research site. Importantly, the large quantity of water present in the air sample will be removed automatically and regeneratively, without affecting the VOCs being measured. This is especially difficult for the critical compounds that this project will target. The dry, concentrated air sample will then be analysed using an innovative two dimensional gas chromatography system, able to de-convolute the complex mixture of VOCs. This would be, to our knowledge, the first ever long-term deployment of such an instrument. By co-locating the new technology alongside existing world-leading measurements made at the NIES Hateruma Observatory (including NOx), exceptional additional value is added to the atmospheric chemistry interpretation. The project builds on collaborative work between Andrews and Saito, with this follow-on activity creating a longer-term programme of atmospheric science research based around shared instrument development and global change observations from Japanese research infrastructure. The project would play to existing strengths of both partner organisations and create a new technological capability to be exploited more widely. It will generate unique new datasets on atmospheric composition that will help Japan in management of air pollution and mitigation of environmental risk, and support UK and Japanese leadership of the science that informs control of the trans-boundary spread of air pollution between countries.