May 22, 2018

expert reaction to Defra’s Clean Air Strategy

DEFRA has published their Clean Air Strategy.

Dr Stefan Reis, Science Area Head for Atmospheric Chemistry and Effects at the Centre for Ecology & Hydrology (CEH), said:

“The new strategy presents a timely recognition of the substantial public health effects caused by air pollution in the UK, as well as globally. The Global Burden of Disease study has demonstrated how much outdoor air pollution affects public health and constitutes one of the most pressing challenge for the management and prevention of non-communicable diseases today. The commitment to work with international partners on new standards to curb vehicle emissions (including those not coming from the tail pipe) is much welcome. However, co-ordinated international action and collaboration are vital to achieve the ambitious targets of 10 µg/m3 for fine particulate matter (PM2.5) concentrations, as the UK receives a considerable amount of secondary inorganic aerosols, a key contributor to PM2.5, from sources outside of the UK, as the 2013 report of the Air Quality Expert Group (AQEG) and CEH research have highlighted. With the UK leaving the European Union, continuing the science-policy dialogue in international fora such as the United Nations Air Convention will be ever more important to address transboundary air pollution challenges.”

Prof Mark Sutton, Environmental Physicist at the Centre for Ecology and Hydrology (CEH), said:

“The brief announcement today requiring farmers to invest in reducing ammonia emissions could herald a key turning point for UK ammonia emissions. Recent trends have suggested that UK would overshoot international ammonia emission limits for 2020 by 20%, linked to a lack of uptake of well-established methods to reduce ammonia emissions.  The proposed change looks innovative in fostering change. However, until the details are published on the timing and scale of requirements and the proposed investment, it will not be possible to comment in detail on how much the proposals are likely to achieve.”

Prof Alastair Lewis, Professor of Atmospheric Chemistry at the National Centre for Atmospheric Science, University of York, said:

“A key eye-catching part of the strategy is the explicit recognition of the more stringent World Health Organization limits for fine particulate matter, PM_2.5, and an ambition to halve the number of people living in areas with concentrations above that limit.  By adopting this new target the UK would pull ahead of the rest of Europe, and indeed virtually every other industrialized nation in the toughness of its standards. Meeting a limit of 10 microgrammes of PM_2.5 per cubic metre of air will be challenging since concentrations are influenced not only by local sources but also reactions of other pollutants in the atmosphere and from further afield, including from mainland Europe.

“The strategy sets out plans for reducing emissions across different source types rather than individual pollutants, in some cases with proposals for specific actions, in others more general ambitions for reductions. The phase-out of diesel trains and the labelling of solvents in consumer products are two of the more interesting specifics.  The strategy also looks serious about finally tackling the long-standing issue of ammonia emissions from agriculture, and it raises the emerging health issue of managing indoor air quality.

“The strategy provides some interesting insight into how sources of air pollutants have changed over time in the UK. In the case of volatile organic compounds (VOCs), historically the overwhelming source to air was from evaporation of petrol, partially combusted fuel and leaking natural gas pipes. Today nearly a fifth of all VOCs come from domestic uses of solvents in the home, almost as much as from industrial processes. The recent popularity of wood burning stoves is named as a lifestyle factor that has grown over the last decade to now seriously impact urban PM concentrations.

“Whilst the Government will always be measured first against their ability to deliver good air quality at a local level, the strategy reflects that the health and ecological impacts do not stop at the borders of individual countries. The strategy is setting out a pathway to achieve some demanding targets that have been agreed for total national emissions, part UK commitments to the UNECE Convention on Long-Range Trans-boundary Air Pollution. The UK has recently signed up to new binding limits in 2020 and 2030, and these require close to a halving of emissions of some pollutants, irrespective of whether local air quality standards are met or not.”

Declared interests

None received.