Continuous chemical speciation of Asian VOC emissions for understanding the growth of surface ozone in East Asia

Lead Research Organisation: University of York
Department Name: Chemistry

Abstract

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.

Planned Impact

This project is anticipated to generate impact in two key areas; the first relates to strategies, policies and agreements for the control of transboundary air pollution, and the second to the generation of economic impacts from the commercialisation of new technologies.

The approaches needed to generate impact are clearly different and are set out in more detail in the pathways to impact, and the timescales also differ. The potential types and scale impacts are described in more detail here. We note that the York labs have a strong track record in both the translation of science into policy and commercialisation. The project includes as Co-I an acknowledged leader in the field of air pollution science-to-policy, in Dr Moller. Lewis and Andrews have both successfully developed new instruments and delivered these to market through collaborations with industry, notably Markes International, Givaudan, Syft Technologies and Anatune Ltd.

Impact on policy.

Growth in ozone in Asia is a major environmental issue and this currently causes harm to both public health and to ecosystems (including the reduction in crop yields). It is a problem that has grown in visibility recently and there is considerable social and political pressure to generate regional solutions through targeted emissions controls. It is a very good time therefore to be generating new science to help inform on future policies to control transboundary pollution, and a unique opportunity to contribute data in a niche area, but one which is fundamental to understanding the nature of the Asian ozone problem. The project will determine the VOC content in background air, both residual primary emissions and later generation gas phase oxidation products. When combined with existing NIES data, this will allow for model analysis of the drivers of ozone to be identified from a chemical perspective, and when data is combined with meteorological analysis also from a source region post of view. It will help provide better quantification of where the key sources of VOCs are in the region and which of those VOCs are most potent at forming ozone. This information can be used by NIES (acting as a national research institute) in its provision of advice to government, and through inclusion in future international activities including GAW and TOAR, to shape strategies for emissions reductions across the region. One single set of data of course cannot in isolation solve such a large problem, but by focusing in this project on an uncertain area of the science, where only these research groups have the combined capability to make progress, a disproportionate degree of influence and impact can potentially be achieved.

Economic impact

Direct economic impact is envisaged through this project through the development of new analytical technologies for commercialisation. [We set to one side the economic gains from improved Asian air pollution controls as being captured as a secondary benefit arising from policy described above]. Although the vehicle for commercialisation will emerge through the project and negotiation with potential partners, the broad scale of the potential economic impact is known to a first approximation. Within the UK, the market for GCxGC instruments and thermal desorption (TD) instrumentation is estimated at around £40-60M pa, and globally at around £600M pa. The measurement of trace organics and VOCs in air, which this project directly addresses through the development of a new TD and water handling technologies, is estimated as a market to grow to around £2B pa by 2020 (Frost and Sullivan market report), with the majority of that growth coming in non-environmental sectors such as defense (explosives), security (drugs), healthcare (breath analysis), utilities (water quality) and food /drink (off-odours). A low power, high reliability, high performance TD technology would address a large unmet user demand where there is little current provision.

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