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Dec 22, 2011, 10:51:08 AM12/22/11

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Science for Environment Policy Air Digest

New ozone hole discovered over the Arctic 16/12/11
For the first time, scientists have identified an 'ozone hole' over the
Arctic, in addition to the well-known ozone hole over the Antarctic.
Unusually persistent low temperatures over the Arctic in early 2011 caused
an unprecedented amount of chemical destruction of stratospheric ozone
there. The authors warn that this is likely to happen again, although it is
presently difficult to predict when this might be.
(more... <> ) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/266na1.pdf>
article (PDF)

Air pollution increases DNA damage associated with disease 16/12/11
A study in the Czech Republic has found a link between exposure to certain
air pollutants and an increase in DNA damage for people exposed to high
levels of the pollution. They found that breathing small quantities of a
polycyclic aromatic hydrocarbon (PAH), called benzo[a]pyrene (B[a]P),
caused an increase in the number of certain 'biomarkers' in DNA associated
with a higher risk of diseases, including cancer.
(more... <> ) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/266na3.pdf>
article (PDF)

Light-duty vehicles exceed EU emissions limits during on-road driving
16/12/11
The nitrogen dioxides (NOx) and carbon dioxide (CO2) emissions of some
light-duty petrol and diesel vehicles are higher during on-road driving
than during standard laboratory tests, according to a new study. This means
that in normal on-road driving, light-duty vehicles, which include
passenger cars and light commercial vehicles, may exceed European emissions
limits and could be having a greater impact on urban air quality than
previously thought.
(more... <> ) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/266na5.pdf>
article (PDF)

Leaked hydrogen fuel could have small negative effects on atmosphere
16/12/11

Using hydrogen as an energy carrier can help reduce air pollution and
greenhouse gas (GHG) emissions associated with fossil fuels, according to
recent research. However, if used on a large-scale, it is important that
hydrogen does not leak significantly into the atmosphere as it might have
some negative environmental effects, such as increasing the lifetime of
methane, increasing climate effects and causing some depletion of the ozone
layer.
(more... <> ) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/266na6.pdf>
article (PDF)

Analysing trends in tropospheric levels of ozone 29/9/11

A new study has analysed trends in ozone levels in the European troposphere
from 1996 to 2005. It indicated that average levels have been increasing
despite reductions in pollutants that influence ozone formation. However,
it also identified year-by-year variations, caused by climate and weather
events, and suggested they could be masking the impact of emission
reductions on long-term ozone trends.

(more...) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/255na3.pdf>
article (PDF)

Researchers assess indoor air pollution across Europe 15/9/11

(more...) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/253na5.pdf>
article (PDF)

A simple model of urban air pollution 8/9/11

Traffic fumes can cause serious health problems, but their distribution and
spread in complex urban environments can be hard to predict. Now,
researchers have created the 'STEMS-Air dispersion model', which can be
used by planners and health authorities to give accurate daily and annual
estimates of exposure to traffic fumes and other forms of air pollution in
cities.

(more...) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/252na6.pdf>
article (PDF)

Improved modelling techniques for predicting urban air quality 8/4/11

A recent study assesses new methods for comparing and predicting air
quality data in Helsinki, Finland and Thessaloniki, Greece, that
significantly improve the capability to analyse and predict air quality in
these cities. There are good indications that the methods could be applied
to other European cities.

(more...) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/252na6.pdf>
article (PDF)

Updated assessment of aviation's impact on the atmosphere 20/1/11

In an update of the 1999 assessment of aviation impacts on climate change
and ozone depletion by the Intergovernmental Panel on Climate Change
(IPCC), a new study has detailed recent research on aviation emissions and
investigated the potential for using alternative aviation fuels.

(more...) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/225na4.pdf>
article (PDF)

Air pollution and climate change: which has greater health impacts? 20/1/11

Air pollution causes serious health problems around the world, however,
some aerosol particle emissions contribute to a cooling effect on the
climate. A recent study has focused on shipping as a source of emissions to
explore whether reducing air pollution to improve human health could
increase the risk of health problems caused by climate change.

(more...) Download
<http://ec.europa.eu/environment/integration/research/newsalert/pdf/225na5.pdf>
article (PDF)

*****************************************************************

New ozone hole discovered over the Arctic

For the first time, scientists have identified an 'ozone hole' over the
Arctic, in addition to the well-known ozone hole over the Antarctic.
Unusually persistent low temperatures over the arctic in early 2011 caused
an unprecedented amount of chemical destruction of stratospheric ozone
there. The authors warn that this is likely to happen again, although it is
presently difficult to predict when this might be.

Ozone depletion occurs naturally each year in the Arctic and the Antarctic
when low temperatures in winter cause polar stratospheric clouds (PSCs) to
form. These clouds help convert harmless forms of chlorine (chlorine
nitrate and hydrogen chloride) into more reactive forms that destroy ozone
(chlorine monoxide). Normally, annual Arctic ozone loss is small compared
to that in the Antarctic, but in early 2011, this study found that it was
far greater than ever seen before in the Arctic, and the amount of ozone
that was destroyed was comparable to that in some Antarctic ozone holes.

The scientists measured ozone loss over the Arctic using instruments
attached to observation balloons and a satellite orbiting the Earth.
Despite some uncertainty over precise levels of ozone depletion, the
scientists estimate that 80% of Arctic ozone in the 18-20 km altitude range
was lost between January and late March 2011. The chemical ozone loss was
nearly double that in 1996, 2000, and 2005, the years with the next highest
Arctic ozone depletion.

According to the study, which was partly supported by the EU RECONCILE
project1, the unprecedented ozone loss in the Arctic was mainly caused by
an unusually long period of low stratospheric temperatures (over the
Arctic) that persisted from December through the end of March, much later
than in other years. The low temperatures also extended over a larger
altitude range (height above the ice sheet) than previously. Together,
these factors led to a higher volume of PSCs forming over a longer time
period, causing greater ozone loss than usual.

A long-term trend towards decreasing stratospheric temperatures in the
Arctic means that an ozone hole is likely to appear again, say the
scientists, but huge differences in winter conditions from year to year
make it extremely difficult to predict when this might be. For example, the
last decade has seen four of the warmest Arctic winters in the past 32
years and also two of the coldest. The variability in Arctic temperatures
is also affected by increasing greenhouse gas emissions, which further
complicates predictions.

Although the Arctic ozone hole in 2011 was confined to a smaller area than
the Antarctic hole, there are concerns that if one occurs in the future, it
may reach parts of the well-populated mid latitudes, as it did briefly in
2011, increasing the risk of mass exposure of people, plants and wildlife
to harmful UV radiation from the sun.

In the 1980s, scientists linked the depletion of Antarctic ozone with
rising levels of certain chemicals from human activity, most notably
chlorofluorocarbons (CFCs). Once they are in the atmosphere, CFCs persist
for many decades, but a global reduction in CFC emissions under the
Montreal Protocol2 has now stabilised the size of the Antarctic ozone hole.

This research highlights the importance of the Montreal Protocol in
reducing atmospheric CFC levels, or the Arctic ozone hole would have become
a regular occurrence long before now, even in relatively mild winters. The
challenge now is to improve the predictive power of current climate models
to estimate when Arctic ozone loss might match, or even exceed, early 2011
levels.

1. RECONCILE (Reconciliation of essential process parameters for an
enhanced predictability of arctic stratospheric ozone loss and its climate
interactions) is supported by the European Commission under the Seventh
Framework Programme. See: www.fp7-reconcile.eu

2. See: http://ozone.unep.org/

Source: Manney, G.L., Santee, M.L., Rex, M. et al. (2011). Unprecedented
Arctic ozone loss in 2011. Nature. DOI: 10.1038/nature10556.

Contact: <mailto:Gloria....@jpl.nasa.gov%20>
Gloria....@jpl.nasa.gov or <mailto:Michelle...@jpl.nasa.gov%20>
Michelle...@jpl.nasa.gov

Theme(s): Air pollution

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 16 December, 2011, Issue 266, “New ozone hole
discovered over the Arctic”, European Commission DG Environment News Alert
Service.

*****************************************

Air pollution increases DNA damage associated with disease

A study in the Czech Republic has found a link between exposure to certain
air pollutants and an increase in DNA damage for people exposed to high
levels of the pollution. They found that breathing small quantities of a
polycyclic aromatic hydrocarbon (PAH), called benzo[a]pyrene (B[a]P),
caused an increase in the number of certain 'biomarkers' in DNA associated
with a higher risk of diseases, including cancer.

Air pollution is a major problem around the world, particularly in urban
areas. In attempt to control regional air pollution levels, the EU has
introduced legal limits for exposure to a variety of different airborne
pollutants. For B[a]P , the EU air quality standard is 1 nanogram per
metre3 (ng/m3) as an annual average that has to be attained where possible
throughout the EU1.

To measure the risk of DNA damage and risk to health caused by exposure to
chemicals, such as PAHs, researchers sometimes use 'biomarkers' – these are
biological features that can provide an indicative picture of risk and
disease. Previous studies have suggested that 'DNA adducts' can be used as
biomarkers to measure exposure to PAHs. These are, in effect, small
molecules, such as PAHs, bound to the DNA. Similarly, 'chromosomal
aberrations' - structural changes to a stretch of DNA - can be used as
biomarkers to demonstrate the effect of some pollutants on DNA.

To test whether there was a possible link between exposure to PAHs and the
frequency of DNA adducts and chromosomal aberrations, the researchers,
supported by the EU EnviRisk and INTARESE projects2, examined DNA from 950
police officers and bus drivers in Prague. The participants, drawn from
three separate studies conducted over a five-year period, all worked
outdoors for more than eight hours a day. Each carried a device to measure
their personal exposure to PAHs and DNA was extracted from the
participants' white blood cells. The researchers also tested a new
technique for identifying chromosomal aberrations called 'fluorescence
in-situ hybridisation', or FISH, which is much more sensitive than previous
techniques.

The results revealed, for the first time, a significant relationship
between exposure to PAHs, the number of DNA adducts and the number of
chromosomal aberrations detected using FISH. In particular, PAH levels and
the occurrence of the two biomarkers were higher in winter than in summer.
In one of the studies, average personal exposure to B[a]P and PAHs in
January was measured as 1.58 ng/m3 and 9.07 ng/m3, respectively. In June,
this dropped to 0.18 ng/m3 and 1.92 ng/m3.

The number of B[a]P-like DNA adducts and chromosomal aberrations were
correspondingly much higher in January than in June. In fact, the number of
DNA adducts strongly mirrored exposure to PAHs in the past 30 days.

These findings are of concern because exposure to more than 1 ng/m3 of
B[a]P has been found to put people at higher risk of developing cancer
later in life. Previous studies have shown that DNA adducts can be an
indicator for cancer several years after exposure and the findings of this
study indicate that DNA adduct biomarkers and chromosomal aberrations
measured using FISH could help health authorities identify individuals at
higher risk of disease.

1. See: http://ec.europa.eu/environment/air/quality/standards.htm

2. Integrated Assessment of Health Risks of Environmental Stressors
in Europe and (INTARESE) and EnviRisk were both supported by the European
Commission under the Sixth Framework Programme. See: www.intarese.org and
http://envirisk.nilu.no/Home/tabid/178/Default.aspx

Source: Sram, R. J., Binkova, B., Beskid, O., et al. (2011). Biomarkers of
exposure and effect – interpretation in human risk assessment. Air Quality
and Atmospheric Health. 4: 161-168. This study is free to view at:
www.springerlink.com/content/8mj322hk77762332/

Contact: sr...@biomed.cas.cz <mailto:sr...@biomed.cas.cz>

Theme(s): Air Pollution, Environment and health

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 15 December, 2011, Issue 266, “Air pollution
increases DNA damage associated with disease”, European Commission DG
Environment News Alert Service.

*****************************************

Light-duty vehicles exceed EU emissions limits during on-road driving

The nitrogen dioxides (NOX) and carbon dioxide (CO2) emissions of some
light-duty petrol and diesel vehicles are higher during on-road driving
than during standard laboratory tests, according to a new study. This means
that in normal on-road driving, light-duty vehicles, which include
passenger cars and light commercial vehicles, may exceed European emissions
limits and could be having a greater impact on urban air quality than
previously thought.

Light-duty vehicles are a major source of air pollution in urban areas: in
2008, they contributed 8% to the NOx emissions and 27% to the carbon
monoxide emissions of the EU. The compliance of light-duty vehicles with
applicable emissions limits is currently verified by emissions tests in the
laboratory under standardised conditions.

To establish whether light-duty vehicles produce more air pollution during
on-road driving than in the laboratory, the researchers used portable
emissions measurement systems (PEMS) to monitor 12 vehicles driven over a
variety of urban and rural roads, including uphill and downhill sections
and motorways. The vehicles included petrol and diesel vehicles and one
vehicle with a petrol-hybrid engine. The researchers recorded carbon
monoxide, NOx, total hydrocarbons and CO2 emissions for each vehicle.

They found that the total hydrocarbon and carbon monoxide emissions of the
tested vehicles generally stayed below the European emissions limits if
vehicles are driven on the road.

NOx emissions were within EU limits for petrol vehicles, but not for diesel
vehicles. In fact, the on-road NOx emissions from diesel vehicle have not
declined significantly over the past ten years and currently exceed the
respective emissions limit by several factors. Looking more closely at the
data, the researchers found that NOx emissions were highest when the engine
was working hardest, such as on uphill sections and motorways. The
researchers also found that CO2 emissions on the road are around 20% higher
than during standard laboratory emissions testing.

However, the researchers note that their study has limitations,
particularly that the number of vehicles tested was relatively small. Also,
although test routes covered a variety of road types, they may not
necessarily be representative of the average driving patterns in Europe.

The results of this study indicate that the current emissions testing in
the laboratory may be insufficient to effectively limit the emissions of
light-duty vehicles under 'real world' driving conditions. The study
confirms the need to complement existing emissions tests in the laboratory
by on-road emissions tests of light-duty vehicles. The research suggests
that the portable emissions measurement systems (PEMS) used for this study
could be a suitable and reliable tool for this purpose.

Source: Weiss, M., Bonnel, P., Hummel, R., Provenza, A., Manfredi, U.
(2011) On-road emissions of light-duty vehicles in Europe. Environmental
Science and Technology. 45: 8575-8581.

Contact: martin...@jrc.ec.europa.eu

Theme(s): Air pollution, Climate change and energy, Sustainable mobility

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 22 December, 2011, Issue 267, “Light-duty vehicles
exceed EU emissions limits during on-road driving”, European Commission DG
Environment News Alert Service.

*****************************************

Leaked hydrogen fuel could have small negative effects on atmosphere

The precise impact of extensive hydrogen use on the chemistry of the
atmosphere is uncertain. Hydrogen, when used extensively, would have to be
produced, transported and stored on a large scale and could leak into the
atmosphere at any of these stages. In addition, air pollutants could be
emitted to the atmosphere during production of the hydrogen, depending on
how it was generated. For example, pollution could occur if hydrogen was
produced from fossil fuel sources.

The study investigated the potential impact on air pollution of the
large-scale use of hydrogen as a fuel in a future mix of energy sources,
using a combination of two modelling systems. A range of future scenarios
of hydrogen use from a global energy model was linked with a global
atmospheric model that simulated changes in air pollutants (carbon
monoxide, nitrogen oxides, sulphur dioxide and hydrogen) in the atmosphere.
It was assumed that hydrogen would be produced from methane, coal or
biomass feedstocks.

Hydrogen leakage from the production, distribution and end-use of hydrogen
fuel varied from 0.3% to 10%, depending on the estimated levels of leakage
throughout the hydrogen fuel chain. In absolute terms, the lower level is
comparable to the amount of hydrogen currently released to the atmosphere
from the combustion of fossil fuels, and the upper limit is five times
today's total hydrogen emissions.

Overall, air quality in the lower atmosphere (the troposphere) was found to
improve if hydrogen was introduced into the future mix of energy sources.
This improvement would occur as a result of the avoided use of fossil fuels
and reduced emissions of carbon monoxide (especially in tropical regions),
nitrogen oxides and sulphur dioxide, despite an increase in nitrous oxide
and volatile organic compound emissions if coal was used to produce the
hydrogen. High levels of hydrogen use also reduce the development of
ground-level ozone, another air pollutant, partly formed from fossil fuel
emissions.

There may also be some climate change impacts, other than through the
reduced use of fossil fuels as a major energy source. The hydrogen could
also potentially act as a GHG itself, and it could cause atmospheric
chemical reactions that extend the lifetime of methane (a GHG) in the
atmosphere, especially under high levels of hydrogen leakage.

A further impact comes from chemical reactions of hydrogen in the
stratosphere (the layer of atmosphere above the troposphere). Especially
under high hydrogen leakage, stratospheric ozone becomes slightly depleted.
However, the overall effect would be small since, under those conditions,
some tropospheric ozone is produced as a result of additional precursor
emissions in leaks.

The findings of this study highlight the importance of minimising hydrogen
leakage if used at large scale and suggest that additional policies on
hydrogen emissions and air pollutants would need to accompany policies that
promote hydrogen energy technologies, according to its authors.

Source: van Ruijven, B., Lamarque, J-F., van Vuuren, D.P. et al. (2011)
Emission scenarios for a global hydrogen economy and the consequences for
global air pollution. Global Environmental Change. 21: 983-994.

Contact: vrui...@ucar.edu

Theme(s): Air pollution, Climate change and energy

*****************************************

Analysing trends in tropospheric levels of ozone

Ozone in the lower part of the earth’s atmosphere (troposphere) is
recognised as a threat to human health and vegetation, and acts as a
greenhouse gas. A major source of ozone is the chemical reactions of
nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the
troposphere. To combat this, national and European legislation have reduced
the emissions of these substances over the past 20 years. To investigate
the impact of reducing these emissions, it is important to establish trends
in ozone levels over time.

The study analysed ozone data from 158 European rural observation sites,
mainly situated in central Europe, from the EU GEOmon project1 from 1996 to
2005. Annual and seasonal trends were determined as well as general
geographic variations.

Overall, the average level of ozone across all the European sites increased
each year by 0.16 parts per billion by volume (ppbv). However, within this
overall trend there were geographical variations. Increases in annual ozone
levels were observed at 54% of stations. Only 11% of stations experienced
decreasing annual levels of ozone and these were mainly in eastern and
south-west corners of Europe.

Very high average levels of ozone were recorded in several Austrian sites
and the largest increase over time was observed in the Po Valley, Italy.
This is a region with large anthropogenic emissions and very static weather
conditions, meaning that accumulating ozone is unlikely to shift.

The research investigated the possible impact of influential events on the
ozone levels, such as the 2003 north-western European heat wave. High
temperatures are known to increase levels of tropospheric ozone and, when
data from this year were removed from the calculations, fewer sites
exhibited increases in annual ozone levels.

The researchers suggested that these extreme events could potentially mask
the effect of emission reductions when considering trends over decades.
Indeed the study found that there was a near uniform decrease in levels of
NOx and VOC emissions in Europe, suggesting they are not reflected in the
observed ozone trends. To take these ‘freak years’ into account a longer
time-series would be required, which may show a stronger relationship
between emissions and ozone levels.

Finally, the research compared the observed levels of ozone with those
simulated by the CHIMERE2 model. The model predicted a smaller increasing
annual trend in the European average level of ozone than the study’s
results at 0.05 ppbv per year. It appears that the method of collecting
data from numerous stations is a robust way to explore regional trends.
However, there was a lack of data from sites in France, Spain and the
Mediterranean area, which may bias the ozone trends towards those in
Central/Northern Europe and longer time series may be needed to account for
individual years where there are particularly high levels of ozone caused
by climate and weather events.

1. GEOmon (Global Earth Observation and MONitoring) was supported by the
European Commission under the Sixth Framework Programme. See: www.geomon.eu

2. See: www.lmd.polytechnique.fr/chimere/

Source: Wilson, R.C., Fleming, Z.L., Monks, P.S. et al. (2011) Have primary
emission reduction measures reduced ozone across Europe? An analysis of
European rural background ozone trends 1996-2005. Atmospheric Chemistry and
Physics Discussions. 11:18433-18485. This study is free to view at:
www.atmos-chem-phys-discuss.net/11/18433/2011/acpd-11-18433-2011.html

Contact: p.s....@le.ac.uk

Theme(s): Air pollution

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 29 September, 2011, Issue 254, “Analysing trends
in tropospheric levels of ozone”, European Commission DG Environment News
Alert Service.

*****************************************

Researchers assess indoor air pollution across Europe

The quality of indoor air varies widely across Europe, according to a
recent study. Poor indoor air quality is mainly due to household products,
outdoor pollution and smoking yielding high levels of organic pollutants
harmful to human health. The study indicates higher levels of indoor air
pollution in southern Europe than in northern Europe, and with an
associated risk of cancer higher than the acceptable unit risk. However the
present data must be improved in A wide variety of organic compounds are
used in household products, such as cleaning materials, detergents, paints,
varnishes and waxes, and emitted by photocopiers and printers. Exposure to
these chemicals in indoor environments is of growing concern as it is
believed that they may be harmful to health. Two groups of chemicals
particularly affect indoor air quality: volatile organic compounds (VOCs)
(e.g. benzene, toluene, xylenes, styrene (BTXS) and terpenes) and
carbonyls, such as formaldehyde and acetaldehyde. These chemicals in indoor
air are not yet regulated by the EU, mainly because there is insufficient
hazard and risk assessment information, although the European Commission is
developing guidelines.

Partly conducted under the EU HEIMTSA project1, this study examined the
findings of previous research conducted over 20 years (1990-2008)
concerning major organic chemicals that affect indoor air quality in the
EU. In addition, the carcinogenic risk of these compounds to human health
was assessed. The results suggest that there is greater pollution of indoor
air from organic chemicals in residential buildings than in non-residential
buildings. This may be the result of legislation controlling exposure to
chemicals in the workplace but not in the home. The study suggests that
residents could be better protected against indoor air pollutants by
labelling schemes for emissions from building materials, domestic
appliances and other consumer products. Guideline limits for significant
indoor contaminants could also be developed and public awareness campaigns
for consumer could be run. Harmful chemicals could also be substituted with
less toxic alternatives.

Regional differences in indoor air pollution include the following:

* Concentrations of naphthalene are higher in southern European countries.
Indoor concentrations are higher where it is used to control moths.
* Styrene and xylene (commonly used in paints, detergents and glues, and is
also present in cigarette smoke and most carpets) levels are higher in
southern Europe than in the north and are mostly associated with cigarette
smoking, even though there is a greater use of carpets in northern
countries.
* Levels of indoor benzene and toluene contamination in the south are two
to three times higher than the north, probably due to materials used for
buildings, cigarette smoking and transport. Major sources come from
outdoors, (e.g. traffic fumes) and depend on building ventilation.

For all studied contaminants, in all countries, the risk of
pollutant-induced cancers was higher than the standard accepted risk
threshold of one extra case per million people exposed to the chemicals. In
contrast, the health effects of non-carcinogenic contaminants were
insignificant, except for formaldehyde. This study highlighted gaps in
data, particularly for Spain, Portugal and new Member States in
south-eastern Europe. In other EU countries, there are not always
sufficient data from a variety of sources, especially in cities and towns,
to provide an accurate picture of indoor air quality. Previous studies have
also analysed data in different ways, which means it is not easy to compare
results across studies. There is a need for harmonisation of monitoring,
sampling and evaluation procedures across the EU at urban and rural levels.

1. HEIMTSA (Health and Environment Integrated Methodology and Toolbox for
Scenario Assessment) was supported by the European

Commission under the Seventh Framework Programme. See: www.heimtsa.eu
<http://www.heimtsa.eu/>

Source: Sarigiannis, D.A, Karakitsios, S.P., Gotti, A. et al. (2011)
Exposure to major volatile organic compounds and carbonyls in European

indoor environments and associated health risk. Environment International.
37: 743–765.

Contact: de...@eng.auth.gr

Theme(s): Air pollution, Environment and health

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 15 September, 2011, Issue 253, “Researchers assess
indoor air pollution across Europe”, European Commission DG Environment
News Alert Service.

*****************************************

A simple model of urban air pollution

Traffic fumes can cause serious health problems, but their distribution and
spread in complex urban environments can be hard to predict. Now,
researchers have created the ‘STEMS-Air dispersion model’, which can be
used by planners and health authorities to give accurate daily and annual
estimates of exposure to traffic fumes and other forms of air pollution in
cities.

Air pollution from traffic and other sources in urban areas has been linked
with respiratory and cardiac illness, yet it can be difficult to measure
accurately how much air pollution people are exposed to. Mathematical
modelling provides an alternative way to estimate exposure in urban areas.
Existing modelling techniques, such as land use regression, can model air
pollution over long timescales but, as they do not account for local
weather conditions, they are not suitable for modelling daily exposure to
air pollution. Instead, dispersion models are often used for shorter
timescales, such as daily predictions. However, dispersion models can be
expensive and require large amounts of data. They can also struggle to
model the effects of many different sources of pollution over a large urban
area.

The STEMS-Air (Space Time Exposure Modelling System – Air pollution) model
aimed to overcome these limitations as it was designed to model many
emissions sources over a large urban area. To test the model the
researchers looked at the distribution of a single air pollutant, PM10,
which has well-established links with health problems, across London, UK.
Daily levels of PM10 were measured at six kerbside air pollution monitoring
sites and the researchers also obtained annual average PM10 levels for 53
sites from the London Air Quality Network website.

They found that, for daily exposure, the STEMS-Air model performed
reasonably well. The results were improved when the researchers included in
the model a measure of background PM10 taken from nearby rural areas. This
helped because the model initially only considered PM10 emissions from
traffic, whereas the kerbside monitors recorded total environmental PM10
levels.

When modelling long-term exposure, STEMS-Air under-estimated PM10 levels
because the annual meteorological data used in the model came from an
exposed site, where higher wind speeds reduced the amount of PM10 present.
The short-term predictions did not suffer the same problem because the
meteorological data here more closely resembled typical city wind speeds.
Despite this, the model still provided a reasonably accurate guide to air
pollution concentrations, which could be improved further by using wind
speed data from a less exposed site.

The researchers caution, however, that STEMS-Air should be used only as a
screening model as it cannot replace formal dispersion models, which use
more data to map relatively small areas in great detail. However, as
STEMS-Air can be used by non-specialists, it is a useful a mapping or
screening tool for anyone, such as planners and health authorities,
interested in air pollution effects on health.

Source: Gulliver, J. & Briggs, D. (2011) STEMS-Air: A simple GIS-based air
pollution dispersion model for city-wide exposure assessment. Science of
the Total Environment. 409: 2419-2429.

Contact: j.gul...@imperial.ac.uk

Theme(s): Air pollution

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 8 September, 2011, Issue 252, “A simple model of
urban air pollution”, European Commission DG Environment News Alert
Service.

*****************************************

Improved modelling techniques for predicting urban air quality

A recent study assesses new methods for comparing and predicting air
quality data in Helsinki, Finland and Thessaloniki, Greece that
significantly improve the capability to analyse and predict air quality in
these cities. There are good indications that the methods could be applied
to other European cities.

The Clean Air for Europe (CAFE) initiative and directive1 proposes the
development of common methods and air quality criteria for improved public
information. The study, funded by the EU2 under the COST ES0602 and
TRANSPHORM projects, tested a ‘computational intelligence’ modelling method
for comparing and predicting air

quality in selected cities (Helsinki and Thessaloniki).

This model allows large data sets to be analysed quickly and efficiently
without needing a priori information about the physical causes of local air
pollution. Instead, computers statistically investigate which factors, such
as traffic, contain the most explanatory information, which can then be
selected for use in forecasting models. This also excludes other factors
which make modelling unnecessarily complex.

The model was comprehensively tested for Helsinki and Thessaloniki. Air
quality data recorded included Particulate Matter (PM), nitrogen oxides and
ozone. Both cities have southern coastlines and part-maritime, part
continental climates, and similar populations of around 1 million. However,
Helsinki is relatively flat and dispersed, while

Thessaloniki is more mountainous and densely populated. Nevertheless, the
modelling was equally effective in both cities at predicting air quality,
suggesting it may be suitable for development toward a continental
standard.

The new model performed better at air quality forecasting than previously
used models, which the researchers believe is a result of their new method
of selecting the most significant model parameters. The study compared
several statistical analysis methods (‘Principal Component Analysis’ (PCA)
and ‘Artificial Neural Networks’ (ANN)) and their capacity to predict air
quality. PCA can identify simple relationships from within multiple data
sets, while ANN can resolve more complex, non-linear relationships. PCA
could explain around 70 per cent of the variability in air quality as
‘non-random’, i.e. attributable to a particular source or cause, but could
not identify every physical cause (about 25 per cent of variability related
to traffic and 20 per cent related to ‘seasonal influences’). ANN
introduced more predictive variables, and found that more are needed to
explain PM at background stations compared with traffic-dominated central
sites.

However, the effectiveness of the models, which can be constructed by the
new method, is limited by the range and completeness of the available input
data. In this study, some episodes of high PM in Thessaloniki were not
predicted, which might have been caused by long-range coarse particle
transport. The dataset of measured variables did not contain enough
parameters to predict these events.

The authors suggest further development of the method is needed to improve
the parameter selection from the PCA and also to improve the artificial
learning for forecasting. The forecasting tool is trained using measured
data - real forecasts would use predictions from meteorological models,
which may also limit the parameters available.

1. http://ec.europa.eu/environment/archives/cafe/index.htm

2. This project was supported by the European Commission under the projects
COST ES0602 and TRANSPHORM. TRANSPHORM is

funded under the Seventh Framework Programme. See: www.chemicalweather.eu
and www.transphorm.eu <http://www.transphorm.eu/>

Source: Voukantis, D., Karatzas, K., Kukkonen, J., et al. (2011).
Intercomparison of air quality data using principal component analysis and
forecasting of PM10 and PM2.5 concentrations using artificial neural
networks, in Thessaloniki and Helsinki. Science of the Total Environment.

409:1266-1276.

Contact: <mailto:kk...@eng.auth.gr> kk...@eng.auth.gr

Themes: Air pollution; Urban environment

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 7 April, 2011, Issue 236, “Improved modelling
techniques for predicting urban air quality”, European Commission DG
Environment News Alert Service.

*****************************************

Updated assessment of aviation's impact on the atmosphere

Aviation levels have increased substantially since the 1960s and are
projected to rise in the future. Emissions from aircraft engines change the
chemistry of the atmosphere and can modify the global climate and deplete
the ozone layer.

Undertaken as part of the EU ATTICA1 project, the research confirms the
major effects on climate change resulting from air traffic emissions,
including: the warming impact of CO2, soot particles, water vapour,
contrails (condensation trails from engines) and increased cirrus cloud
formation; and the cooling impact from sulphate particles. These results
are for subsonic aircraft that fly at altitudes ranging from 8-12 km.

In addition, aviation nitrogen oxide emissions have both a warming effect
through the formation of ozone, a greenhouse gas (GHG), in the lower
atmosphere, and a cooling effect, through the destruction of methane, also
a GHG. The overall impact on the climate from nitrogen oxide emissions is
probably warming. However, nitrogen oxide emissions from subsonic aircraft
do not appear to deplete ozone in the upper atmosphere.

Estimates suggest aviation contributed about 3.5 per cent (excluding the
effects on increased cloudiness) to the total climate warming from human
activities in 2005, and this figure is expected to rise to 4 to 4.7 per
cent by 2050. In 2005, 2.5 per cent of man-made CO2 emissions came from
aviation. Projections suggest CO2 from aviation in 2050 will increase 2.7
to 3.9 times, compared with 2000 levels.

Further work is needed to understand and quantify the effects of aviation
on clouds, including contrails, increased cirrus cloud development from
spreading contrails and altered properties of clouds from soot emissions.
Nevertheless, the effect of contrails and probable additional cloud
formation is likely to have an overall warming impact on the climate.

Technological advances have the potential to mitigate some of aviation’s
impacts on climate change and the ozone layer but could take some time to
reach the market: aircraft are generally in use for around 20-25 years and
although feasible, technology that significantly reduces emissions of CO2,
nitrogen oxide, water and aerosols typically takes time to develop. In
addition, technological advances would probably require trade-offs between
reducing nitrogen oxide emissions and contrail development (at a cost of
higher fuel consumption) and reducing CO2 emissions through lowering fuel
consumption. Operational changes, such as adjusting flight altitudes and
times of flights, could potentially cut down contrail formation and reduce
the impact on the climate.

Conventional kerosene jet fuels could be replaced with alternative fuels,
such as liquid hydrogen or biofuels. Liquid hydrogen produces water and
nitrogen oxide, but not carbon emissions. Overall climate impacts depend on
the energy sources used to produce the liquid hydrogen. Substantial changes
to the aircraft design, general infrastructure and fuel production would be
necessary and would probably only occur as part of a wider hydrogen-fuelled
economy.

1. ATTICA (European Assessment of Transport Impacts on Climate Change and
Ozone Depletion was supported by the European Commission under the Sixth
Framework Programme. <http://www.pa.op.dlr.de/attica>
www.pa.op.dlr.de/attica

Source: Lee, D.S., Pitari, G., Grewe V. et al. (2010) Transport impacts on
atmosphere and climate: Aviation. Atmospheric Environment. 44: 4678–4734.

Contact: D.S...@mmu.ac.uk

Theme(s): Air pollution, Climate change and energy

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 20 January, 2011, Issue 225, “Updated assessment
of aviation's impact on the atmosphere”, European Commission DG Environment
News Alert Service.

*****************************************

Air pollution and climate change: which has greater health impacts?

The health effects of exposure to airborne particles emitted from human
activities, such as the burning of fossil fuels, is a major cause of global
ill health and premature deaths. For example, exposure to particulate
matter (PM10) in urban areas is estimated to cause around 800,000 early
deaths every year and a further 2 million deaths arise from inhaling indoor
smoke from solid fuel fires around the world.

Supported by the European-funded EUCAARI project1, this study investigated
some of the complex relationships between air pollution, health problems
and climate change by examining the impact of shipping on human health.
Ships contribute to aerosol pollution by releasing sulphur oxides, nitrogen
oxides and PM to the atmosphere.

Aerosol emissions can also affect the climate by having either a warming or
a cooling effect. For example, black carbon (or soot) has an overall
warming effect, because it absorbs the sun’s radiation. Other particles
(e.g. sulphates) produce a net cooling effect by reflecting back the sun’s
radiation, altering the reflective properties of clouds or affecting
atmospheric circulation patterns. However, on balance, the combined effect
of aerosol emissions from shipping is that of cooling.

Although warmer temperatures could have local benefits, such as fewer
winter deaths, climate change will create extra health burdens. For
example, a 0.4˚C increase in temperature in 2000 (compared with the
1961-1990 average) is estimated to have caused 160,000 climate-related
deaths from malaria, diarrhoea, malnutrition, heatwaves and floods.

The researchers analysed the ‘total health effects’ (the combined number of
deaths from exposure to air pollutants and climate change) but were not
able to determine whether shipping emissions had overall positive or
negative effects on human health. For example, one estimate suggests
shipping emissions could account for 63,000 deaths a year due to air
pollution, but climate cooling from emissions could potentially save 20,000
lives. The ‘total health effect’ would therefore be 43,000 deaths.

Despite a number of uncertainties about calculating the health effects
caused by air pollution and climate change, the researchers suggest there
are some short-term benefits from emissions that cause climate cooling.
Therefore, it would be preferable to focus mitigation efforts initially on
reducing pollutants that cause climate warming, such as black carbon.

Since the major impacts from shipping typically occur within 400 km from
the shore and the busiest shipping lanes are found off South East Asia,
Europe and North America, the researchers suggest a geographic focus on
regulations might be beneficial. Any efforts to reduce air pollution should
take into account the impact such reductions would have on warming the
climate.

1. EUCAARI (European Integrated Project on Aerosol Cloud Climate Air
Quality Interactions) was supported by the European Commission under the
Sixth Framework Programme. See: www.atm.helsinki.fi/eucaari

Source: Löndahl, J., Swietlicki, E., Lindgren, E. and Loft, S. (2010)
Aerosol exposure versus aerosol cooling of climate: what is the optimal
emission reduction strategy for human health? Atmospheric Chemistry and
Physics. 10: 9441–9449.

Contact: jakob....@nuclear.lu.se

Theme(s): Air pollution, Climate change and energy, Environment and health

Source: “Science
<http://ec.europa.eu/environment/integration/research/research_alert_en.htm>
for Environment Policy”, 20 January, 2011, Issue 225, “Air pollution and
climate change: which has greater health impacts?”, European Commission DG
Environment News Alert Service.

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Subject: [cenn] Science for Environment Policy Air Digest

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