Air Quality; Measurement, standardisation, and quantification of airborne contaminants
Submitting InstitutionsUniversity of St Andrews,
University of Edinburgh
Unit of AssessmentChemistry
Summary Impact TypePolitical
Research Subject Area(s)
Medical and Health Sciences: Public Health and Health Services
Summary of the impact
Impact type: Public Policy
Significance: The research provided evidence for formulation of
government policies to ameliorate poor air quality, to which fine
particulate matter (PM2.5), O3 and NO2
are the most important contributors; PM2.5 alone reduces
average life expectancy in the UK by 6 months and costs £9bn-£20bn a year.
The research has been incorporated into UK national guidance and
policy-evidence documents for Defra, the Health Protection Agency, and the
Beneficiaries are the public and the environment.
Research; date; attribution: EaStCHEM research (1995-2011) (a)
established reliable techniques to measure NO2 for a national
protocol, and (b) quantified the impact of pollutant emissions on PM2.5
and O3 concentrations, and on hospital admissions and deaths.
Heal (EaStCHEM) led the research and wrote, collaboratively in some cases,
the reports and the work cited.
Reach: UK wide.
Background: Air pollution is the environmental factor with the
greatest impact on health in the EU, with 16-30% and 15-17% of the EU
urban pollution estimated to be exposed to levels of PM2.5 and
O3 greater than the EU limit values.[EEA,
2012]. Air quality in Europe — 2012 report. EEA Report No 4/2012,
European Environment Agency] In the UK, poor air quality is estimated to
reduce average life expectancy by ~6 months [COMEAP,
2010]. The mortality effects of long-term exposure to particulate
air pollution in the United Kingdom, UK Department of Health Committee on
the Medical Effects of Air Pollution] and cost £9bn-£20bn in adverse human
health impacts alone.[EAC,
2010].'Air Quality' House of Commons Environmental Audit Committee,
5th report] NO2 is the pollutant causing the
greatest number of failures of air quality standards in the UK. Heal's
group (EaStCHEM) has led air pollution research on all three of the most
important air pollutants; NO2, PM2.5 and O3.
(A) Measurement of ambient NO2 by passive
diffusion tube; improved accuracy and quantification of errors
Measurement of ambient NO2 by passive diffusion tube is widely
used in the UK as part of air quality assessments required by law. From
1995 onwards, research led by the Heal group (EaStCHEM) showed that this
method is subject to inaccuracies, in particular overestimation caused by
the within-tube reaction between co-diffusing NO and O3 to form
additional NO2, and an effective shortening of the assumed
diffusion path length caused by wind turbulence across the entrance of the
tube. Through field deployments and numerical modelling these biases were
quantified for locations of varying ambient chemical and meteorological
conditions.[1,2] Parallel research defined optimal methods for the
adsorbent preparation and post-exposure chemical analysis. This
research was initiated in collaboration with Prof. Cape of the NERC Centre
for Ecology & Hydrology and Honorary EaStCHEM professor but was
subsequently carried out entirely in the Heal group. The work led to more
accurate and reliable measurements of atmospheric NO2
concentration and Heal's methods are now incorporated into protocols
applied to measurements of NO2 for statutory air quality
assessments in all urban areas in the UK (estimated >139,000 NO2
measurements costing £0.5 M annually).[S1]
(B) Characterisation of sources of airborne particulate matter (PM)
Research led by the Heal group (EaStCHEM) in 2007-09 quantified the
proportions of contemporary and fossil carbon in samples of PM2.5
via accelerator mass spectrometric determination of the carbon-14
radioisotope. A key finding was that around half the carbon was shown to
be contemporary rather than fossil, which was higher than anticipated.
This finding has been important for informing PM2.5 reduction
Research carried out in 2012 for the Scottish Environment Protection
Agency, SEPA, (in collaboration with Dr Vieno from the Centre for Ecology
& Hydrology) used an atmospheric chemistry transport model to quantify
the sensitivity of components of PM2.5 in Scotland to
reductions of primary PM2.5 or gaseous inorganic precursors (SO2,
NOx, NH3) from industry and shipping within or
outside of Scotland. A key finding is that reductions in these
components are most sensitive to reductions in ammonia emissions
regionally but that the greatest reductions in population exposure are
achieved nationally by reductions in primary PM2.5 emissions.
These results are being used by SEPA and the Scottish Government to
develop policy on reduction of PM2.5 in Scotland.
(C) Quantification of the current and potential future UK health
burden from exposure to ambient ozone
Research led by the Heal group in 2011 used an atmospheric chemistry
transport model to produce time-series of hourly surface O3
concentrations at 5 km spatial resolution across the UK for the
present-day and for possible future scenarios of different precursor
emissions and increased temperatures from climate change. The O3
concentrations were used to calculate numbers of regionally-disaggregated
deaths and hospital admissions that may be attributable to O3
currently and in the future. The research shows that over a time
horizon of a few decades policy actions that reduce man-made emissions to
the atmosphere can have substantially greater health benefits than adverse
impacts through O3 via climate change but that the O3
health benefits are extremely sensitive to the exact trends in the
man-made emissions that are followed.
Heal, M. R.: PI who led the research in EaStCHEM, Sept. 1994 to date.
Hamilton, R.P, O'Donoghue, M.A.; PhD students in the Heal group.
Doherty, R.D., Stevenson, D.S.; Naysmith, P., Cook, G. T., Xu, S.,
Raventos, D. T., Harrison, R. M., Bigg, M.; collaborating staff in other
departments and UK academic institutions.
Cape, J.N., Vieno. M.; staff at the Centre for Ecology and Hydrology,
Edinburgh (CEH) (Cape was also an Honorary Professor in EaStCHEM (now
Laxen, D., Laxen, K., Heaviside, C., Vardoulakis, S.; staff at non-HEI
institutions (consultancy and public sector).
References to the research
Underpinning research has been published in international,
high-quality, peer reviewed, journals and reports, and receives
citations from across the research area: Atmospheric Environment is
one of the top journals in the field of air quality research.
 * Heal, M. R., Cape, J. N. (1997) A numerical evaluation
of chemical interferences in the measurement of ambient nitrogen dioxide
by passive diffusion samplers, Atmospheric Environment 31, 1911-1923. doi:10.1016/S1352-2310(97)00025-3.
[34 cits, JIF 3.1]
 * Heal, M. R., O'Donoghue, M. A., Cape, J. N. (1999)
Overestimation of urban nitrogen dioxide by passive diffusion tubes: a
comparative exposure and model study, Atmospheric Environment 33, 513-524.
[39 cits, JIF 3.1]
 Hamilton, R. P., Heal, M. R. (2004) Evaluation of method of
preparation of passive diffusion tubes for measurement of ambient nitrogen
dioxide, Journal of Environmental Monitoring 6, 12-17. doi:10.1039/b311869j.
[6 cits, JIF 2.00]
 * Heal, M. R., Naysmith, P., Cook, G. T., Xu, S.,
Raventos, D. T. and Harrison, R. M. (2011) Application of 14C
analyses to source apportionment of carbonaceous PM2.5 in the
UK, Atmospheric Environment 45, 2341-2348.
doi:10.1016/j.atmosenv.2011.02.029. [18 cits, JIF 3.1]
 Heal, M. R., Doherty, R. M., Heaviside, C., Vieno, M., Stevenson, D.
S., Vardoulakis, S. (2012) Health effects due to changes in air pollution
under future scenarios, in Health Effects of Climate Change in the UK
2012: Current evidence, recommendations and research gaps, (ed.
Vardoulakis, S. and Heaviside, C.), Health Protection Agency, UK. ISBN
[An anonymously peer-reviewed chapter; 4 reviewers selected by the HPA.]
Details of the impact
Public Policy: Air quality and climate change science and policy
actions have complex linkages. The research above provided both the sound
scientific evidence base and expert interpretation of that science for the
UK government and regulatory agencies to establish air quality measurement
standards and policy actions.[S1]
NO2 The research in Section 2(A) underpinned
major parts of the standardisation and improvement in protocols for the
measurement of NO2 by passive diffusion tube in the UK. Heal
was an invited member on the working group for 'Harmonisation of Diffusion
Tube Methods' and references [1-3] are cited in the 2008 Defra report. 'Diffusion
tubes for ambient NO2 monitoring: practical guidance for
laboratories and users.'[S2]
The beneficiaries are Defra and the Local Authorities which are required
to measure ambient NO2 in their areas under the legal framework
of the UK Air Quality Strategy, and the commercial laboratories contracted
to provide these measurements for the Local Authorities. These procedures
are now compulsory for air quality reviews to be accepted by Defra.
The 2011 AEA group report [S3] indicates that the implementation of these
standardised procedures is slowly making improvements to the measurement
of NO2 by passive diffusion tube.
The impact of Heal's research is testified by the Senior Air Quality
Consultant at AEA Technology plc a corroborating letter [F1] which also
"Dr Heal was an active and productive member of the working group. In
particular, Dr Heal's research findings in this field were important
contributions to the desired impact of harmonised protocols for
application by users of NO2 passive sampler measurement across the UK...
The measurement results often feed into potentially expensive decisions
(such as declaration of an Air Quality Management Area). It is therefore
important that the results of these measurements are consistent and
reliable...Dr Heal's ongoing research in this field (in particular, the
effects of meteorological factors on diffusion tube performance)
continues to provide important input to the scientific community's
understanding of this much-used measurement technique..."
PM2.5 The research quantifying sources of carbon
in PM2.5 described in Section 2(B), and ref 5 (section 3) is
cited in the report 'Fine particulate matter (PM2.5) in the
United Kingdom' 2012, PB13837,[S4] written for Defra for assessment and
recommendations on the concentrations, sources and trends of PM2.5
in the UK. The research is also part of evidence contained within the 2010
report commissioned by the UK environment agencies (EA, SEPA and DENI) 'PM2.5
in the UK'.[S5] The research described in Section 2(B) on emission sources
potentially controllable within Scotland is part of the 2012 report 'PM2.5
in Scotland' presented to SEPA which analyses potential policy levers
available to SEPA for amelioration of PM2.5.[S6] SEPA is
currently considering this report; SEPA's Local Air Quality Management
Specialist states in a supporting letter [F2] " this kind of research
helps SEPA to carry out its duties (such as protecting and improving the
environment)...We are also pleased to see that sections of the PM2.5
in Scotland report have been referenced in several internal and
O3 The research (sect 2(C), ) has led to new
public health recommendations to raise public awareness of the adverse
health effects of surface O3, and to strengthen warning systems
with targeted ozone alerts for high risk groups. It forms part of the
evidence presented in 2012 to the Dept of Health and the Health Protection
Agency for their plans for preparedness and mitigation of health effects
from air pollution and climate change.[S6] Air Pollution and Climate
Change Group Leader at Public Health England confirmed, in a supporting
letter "The Health Protection Agency...commissioned the research
presented ... The research showed that present-day ozone-related
mortality in the UK is estimated to be up to around 11,900 premature
deaths per year, and ... increase of around 500 additional premature
deaths due to increasing surface ozone in a higher-temperature
future...The output and recommendations in this report are helping
inform policy options and preparedness actions for the future impacts of
ozone on the population...Dr Heal led a team that carried out this
excellent research work ..."[F3]
Sources to corroborate the impact
[S1] Heal's research underpins his membership of the UK government's Air
Quality Expert Group in 2001-2009 and 2012-current.
[F1] A corroborating letter is provided by the Senior Air Quality
Consultant, AEA Technology plc., Gemini Building, Harwell, Didcot, OX11
[S2] Measurement recommendations: Diffusion tubes for ambient NO2
monitoring: practical guidance for laboratories and users. report
no. AEAT/ENV/R/2504, 2008, by the Defra Working Group (of which Heal was
an invited member). AEA Energy & Environment, Didcot, UK. http://uk-air.defra.gov.uk/reports/cat05/0802141004_NO2_WG_PracticalGuidance_Issue1a.pdf.
Heal was also acknowledged particularly for input on diffusion tube
[S3] The effect of improved measurements: Investigation of the
effects of harmonising diffusion tube methodology, Report no.
AEAT/ENV/R/3122, 2011. Loader, A., Willis, P. And Targa, J., AEA Group,
Didcot, UK. http://uk-air.defra.gov.uk/reports/cat05/1108030957_Harmonisation_Follow-Up_Report_issue_2.pdf.
[S4] Fine particulate matter (PM2.5) in the
United Kingdom. 2012, report no. PB13837. A report by the Air
Quality Expert Group, prepared for Department for Environment, Food and
Rural Affairs, Scottish Government, Welsh Government and Department for
Environment Northern Ireland http://uk-air.defra.gov.uk/library/reports?report_id=727.
[S5] PM2.5 in the UK, ER12, 2010.
Laxen, D., Moorcroft, S., Marner, B., Laxen, K., Boulter, P., Barlow, T.,
Harrison, R.M., and Heal, M.R. Scotland & Northern Ireland Forum for
Environmental Research Report ER12. pp.212.
[S6] PM2.5 in Scotland. Laxen, D.,
Laxen, K., Heal, M.R., Vieno, M., and Bigg, M. A report for the Scottish
Environment Protection Agency, 2012
[F2] Corroborating evidence of expert advice provision to the environment
agencies in letter from The Local Air Quality Management Specialist,
Scottish Environment Protection Agency.
O3 and public health
[S7] Health effects due to changes in air pollution under future
scenarios, Heal, M. R., Doherty, R. M., Heaviside, C., Vieno, M.,
Stevenson, D. S. and Vardoulakis, S.. Chapter 3 in Health Effects of
Climate Change in the UK 2012: Current evidence, recommendations and
research gaps, ed. Vardoulakis, S. and Heaviside, C., Health
Protection Agency, UK. ISBN 978-0-85951-723-2. 2012. http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1317135969235.
[F3] Corroboration of expert advice provision on the potential
current and future health effects of O3 in the
UK:, Group Leader, Air Pollution and Climate Change, Public Health