Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Understanding Secondary Inorganic & Organic Aerosol - AQ0732

The secondary component of atmospheric particulate material is complex and the most difficult fraction to quantitatively understand. Ammonium sulphate and ammonium nitrate, the major contributors to Secondary Inorganic Aerosol (SIA) are formed by the atmospheric oxidation and reaction of precursor gases (SO2, NOx) with NH3 and comprise a major component of fine particulate matter. Secondary organic aerosol (SOA) components are formed by the atmospheric oxidation of precursor gases emitted from both man-made and natural sources. The profile of the emission of man-made volatile organic compounds (VOCs) precursors may be subject to changes in response to legislative controls and the natural emissions may change with environmental conditions. There are forthcoming EU and UK legislative requirements to reduce exposure to particulate material and the targets will be difficult to meet without addressing the substantial contribution from secondary material. It is therefore important to understand how secondary aerosol formation and transformation depends on the emissions and fundamental processes.
It is proposed to undertake a review of existing evidence regarding the contribution of SIA and SOA to PM concentrations, to identify and prioritise any knowledge gaps relevant to UK air quality policy; and make recommendations for further studies that could be undertaken to fill the evidence gaps identified. This will be achieved by focusing the atmospheric aerosol resources of the National Centre for Atmospheric Sciences on the policy-relevant aspects of their research, distilling their experience and expertise on secondary aerosol into a practically usable form (in addition to pulling together various recent, ongoing and emerging datasets).
It is expected that Defra will use the review to direct resources into filling the gaps in evidence that is used to guide policy. To this end, a short policy-focused section or separate summary of the review will be provided as part of the final reporting.
Directly following the project specification, the objectives are to:
1. Undertake a review of existing evidence regarding the contribution of secondary aerosol to PM concentrations;
2. Identify and prioritise any knowledge gaps relevant to UK air quality policy; and
3. Make recommendations for further studies which could be undertaken to fill the evidence gaps indentified.

In order to address the objectives, the project deliverables will comprise:
i) Attendance at a project kick-off meeting to be held at Defra, Ergon House, London (Week 1)
ii) A brief summary note of the kick-off meeting and project plan / timetable (Week 2)
iii) Agreement of final delivery plan for the project and final report structure and content (Week 2)
iv) Short milestone reports to be submitted with each invoice providing details of progress (ongoing, 4-weekly)
v) A draft final report for comment by Defra detailing the project’s findings including the evidence gaps identified that are relevant to Defra policy, together with clear recommendations on the work Defra should undertake to close these evidence gaps (Week 14)
vi) A draft brief summary note summarising the main findings of the project for comment by Defra (Week 14)
vii) Finalised main report and summary note (Week 16)
viii) Policy-focused section or separate summary of the review (Week 16)
viii) Attendance at a project close meeting and delivery of a short presentation summarising the results of the project to be held at Defra, Ergon House, London (Week 16)

The timing of many of the deliverables is dependent on the timescales of Defra responses and actions (item iii) and acceptance of v) the draft final report and vi) the draft summary note). If there are delays in these responses, there will be consequent delays in the delivery of subsequent deliverables.

The approaches and workplan outlined in 2.3a are designed to provide the deliverables on the outlined timescales.
Project Documents
• FRP - Final Report : AQ0732 Understanding secondary inorganic and organic aerosol   (2901k)
Time-Scale and Cost
From: 2013

To: 2013

Cost: £45,000
Contractor / Funded Organisations
University of Manchester
Fields of Study
Air Quality