Air pollution remains a concern for public health and the environment,
according to the most recent analyses published by the European Environment Agency. 2013 is the Year of Air!
We are starting today series on air pollution first article from Chris Sherrington, who is an environmental economist,
with PhD research into socio-economic constraints on
the development of renewable energy in the
UK.
There’s something undeniably
appealing about a wood fire and even the smell of wood smoke wafting down from
someone’s chimney. Perhaps it stirs something deep within us, evoking a time
when fire meant safety, and an alternative to raw food, in a world much more
dangerous than that we inhabit today. A gas hob and a combi boiler just don’t
offer the same appeal. Whether it be this ancestral attachment, or the more
prosaic drivers of increased gas and electricity prices, burning wood is
enjoying a resurgence. Sales of domestic woodburning stoves have rocketed over
the past few years.[1]
Wood-burning is
attractive to many who see it as harmless, homely and, since wood is a
renewable resource, green. But I’m increasingly concerned that wood has a range
of environmental downsides as a fuel. In this article I want to ask whether we
understand what the trend for biomass means for air quality. The answer, as we
shall see, is yes - but also no. It is certainly not clear that air quality
legislation is geared up to tackling what may be a growing problem.
While there is increasing
evidence that particulate air pollution derived from wood-burning stoves can
lead to a number of adverse health effects, the magnitude of these impacts is
little understood. I plan to return in a future article to the nature of the
damage for which there is evidence, but suffice it to say that there are
associations with acute and chronic illnesses. Our lack of a clear
understanding is in large part due to the fact that while such emissions are,
in theory, subject to regulations intended to protect UK air quality, no-one
really knows what is being burnt by whom. Meanwhile, enforcement of existing
legislation would appear to be virtually non-existent.
Anti-smoking
law
The Clean Air Act 1993
(a consolidation of 1956 and 1968 legislation) aims to safeguard public health
from emissions of smoke. In particular it empowers local authorities to declare
smoke control areas in which, under Section 20, it is an offence to emit smoke
from chimneys. However, households in those areas may use an “authorised”
smokeless fuel, which could be
(a) anthracite;
(b) semi-anthracite;
(c) electricity;
(d) gas;
(e) low volatile steam
coals; or
(f) one of the fifty
nine fuels described in the current Smoke Control Areas (Authorised Fuels)
Regulations[2].
These are typically briquettes or fire logs.
In addition, Section
21 of the 1993 Act provides that:
the
Secretary of State may, by order, exempt specified classes of fireplace from
the provisions of Section 20 if satisfied that they can be used for burning
fuel other than authorised fuels without producing any, or a substantial
quantity of, smoke.
This does not mean
that exempt fireplaces are allowed to burn any fuels. The types of fuel
permitted to be used with each exempt appliance listed in the current Smoke
Control Areas (Exempt Fireplaces) Regulations[3], are
clearly identified. Moreover, the regulations specify that appliances are to be
operated according to specific parameters, typically relating to airflow. For
example, some appliances must be fitted with mechanical stops to prevent
closure of the air control beyond a certain position; a fire that has little
oxygen burns less cleanly and produces more smoke.
Compliance with the
regulations is therefore no simple matter, requiring knowledge of whether you
live in a smoke control area, and if so, the specific fuels that may be burned
in your particular appliance, and the restrictions on their operation.
While the regulations
are clear and specific, that doesn’t make them easy to enforce. Good monitoring
is the key, but when dealing with a huge number of point source emitters, producing
variable and intermittent emissions this is a considerable challenge. It is
particularly acute bearing in mind that this task falls to cash-strapped local
authorities.
I recently spoke with
a local authority pollution control officer who expressed the opinion that
there was widespread understanding among householders of the requirements in
respect of smoke control areas. I find this questionable – but even if the
rules are understood, this does not mean everyone is acting within the letter
of the law. The officer further explained that enforcement typically stems from
complaints by members of the public. Essentially the approach taken is reactive,
and based on neighbours’ perceptions of nuisance rather than any objective measure
of air quality.
With wood-burning
stoves on the rise, perhaps we need to think again about how to monitor and
enforce in this area if we’re to avoid a return to the smoggy air of industrial
Britain. A feasible alternative might be to require every household wanting to
use a solid fuel burning appliance to apply for a licence, in which they would
have to describe the appliance and the fuel used. Other details relevant to
regulatory risk could also be recorded, such as whether it was the primary or
an auxiliary source of domestic heat.
This simple step would
certainly increase householders’ awareness of authorised fuels, permitted
appliances, the fuels they could burn in these appliances, and the associated operational
restrictions. It would help to bring into line those who inadvertently flout
the regulations.
It would also greatly
help local authorities, by enabling them to focus regulatory resource on
heavier users and those with less efficient appliances, alongside random
checks. If smoke was spotted or reported from a home that had no licence, this
would attract enforcement.
Equally importantly,
knowing the number, and location, of households using solid fuel combustion as
the primary or secondary source of domestic heat, would assist in developing a
better picture of the extent of the emissions produced within any given area or
across the UK.
While this could be a
useful first step, there are many more questions to be answered: On what basis
should smoke control areas be chosen, and what should we actually be looking to
control? The focus of the Clean Air Act is squarely on visible smoke. There is
no consideration of, for example, particulate matter, nitrogen oxides, or
sulphur dioxide. With our greater information and computational power should we
not now be considering the cumulative impacts of domestic wood smoke in
specific locations, taking account of variations in ambient air quality, and
the number of people affected?
The health impacts of
specific emissions will vary depending on factors such as topography, weather
and the number of nearby ‘sensitive receptors’- notably us, that may be harmed
by the presence of the smoke. The Clean Air Act does not do this. In theory,
every single house in the country could burn solid fuel, in ways fully
compliant with the Act, with unimaginable consequences for the air that we
breathe. While the implementation of the original Clean Air Act in 1956 undeniably
led to considerable health improvement, it is arguably not fit for purpose in
2013. Moreover, with DECC enthusiastically promoting the combustion of biomass
through the Renewable Heat Incentive, I do wonder whether the issue of air
quality is receiving the full attention of central government.
From 1st
April 2013 local authorities will take on a range of public health
responsibilities, giving them a much stronger incentive to take action on activities
that may have detrimental effects. The inclusion of air pollution as one of the
health protection indicators in the Public Health Outcomes Framework[4] will
thus enable Directors of Public Health to prioritise action on air quality in
their local area. However, without knowing the extent to which the domestic
burning of solid fuel contributes to poor local air quality, identifying
cost-effective interventions will be difficult. Accordingly, I suspect that any
subsequent action may well focus solely on emissions from transport, where data
quality is better but the marginal abatement costs would, I imagine, be much
higher. Appropriate, cost-effective, management of our desire for a living
flame therefore appears dependent on being able to accurately identify and attribute
impacts, and the extent to which the evidence enables us to do this is
something I will be exploring in a future article.
Chris Sherrington
This article first
appeared on the Isonomia
blog at http://www.isonomia.co.uk/?p=1558
[2] Note that different regulations cover England, Wales, Scotland
& Northern Ireland
[3] Note that different regulations cover England, Wales, Scotland
& Northern Ireland
[4] Department of Health (2012) Healthy Lives, Healthy People:
Improving Outcomes and Supporting Transparency. Part 2: Summary Technical
Specifications of Public Health Indicators, January 2012
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