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Challenges Faced in Relation to Indoor Air Quality and Ventilation

PCA Conference 2017

Clive ShrubsoleSenior Research Associate (Healthy Buildings)

UCL Institute for Environmental Design and EngineeringThe Bartlett School of Environment Energy and ResourcesUniversity College London (UCL)

UCL Institute for Environmental Design & Engineering

Stating the obvious….

What do we mean by Indoor Air Quality (IAQ)?

‘Indoor Air Quality (IAQ) refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants’ (Environmental Protection Agency).

How about Indoor Environmental Quality (IEQ)?

‘Indoor environmental quality (IEQ) refers to the quality of a building’s environment in relation to the health and wellbeing of those who occupy space within it. IEQ is determined by many factors, including lighting, air quality, and damp conditions’ (Centres for Disease Control and Prevention)

What do we mean by Ventilation?

‘The provision of fresh air to a room, building, etc.’ (Oxford English Dictionary)


Factors Impacting IAQ

• Policy and Governance - New and Existing Buildings

• Outdoor Sources: Location – Geography/Meteorology

• Indoor Sources (Source Control)

• Ventilation

• Deposition to Surfaces and Chemical reactions.

• Occupant Behaviour (Lifestyle Changes)


Policy and Governance – New and Existing Buildings:The drive for energy efficiency

As the proposed energy efficiency standards in Part L of the Building Regulations are likely to result in more airtight buildings, it is therefore……

……necessary to amend Part F of the Building Regulations at the same time to ensure that adequate ventilation is provided.


Ventilation/Energy Efficiency trade-offs

What will be the practical optimum balance between improving energy efficiency via infiltration/ventilation heat loss control and the associated health impacts due to changes in IAQ?


Designing Out Poor Indoor Air Quality:Ventilation and Source Control


Guidance Documents for IAQ design


Design factors affecting indoor pollution concentrations

(+) Ingress of external pollutants

• Infiltration via permeabilities in the building envelope, trickle vents

• Windows and doors.

• Ventilation system (Filtration and Maintenance)PSV, MEV, MVHR

• Intakes away from extracts and external sources

• Location and orientation relative to external pollutant source


Design factors affecting indoor pollution concentrations

(-) Pollutant removal

• Exfiltration via permeabilities in the building envelope

• Windows and doors

• Deposition onto surfaces. Re-suspension?

• Ventilation issues: closed trickle vents , blocked air bricks, PSV

• Extraction equipment: appropriate, close to source and switched on! MEV

• MVHR systems ☺ Filtered


Pollutants in the Home: Indoor Sources

Source: Crump D. Maintaining Good Air Quality in Your Home. BRE IP 9/04. Garston: BRE, 2004


The ASBP is a cross sector, not for profit organisation, comprising, building product manufacturers and distributors, specifiers, designers, contractors, public interest and sustainability organisations, academics and other building practitioners.

‘Committed to accelerating the transition to a high performance, healthy and low carbon built environment by championing the increased understanding and use of building products that meet demonstrably high standards of sustainability’.

Products: materials low embodied carbon, sustainably sourced and have low emissions

http://asbp.org.uk/


Pollutants in the Home: Indoor Sources

Pollutant Sources Health Impacts

Nitrogen dioxide (NO2) Heating and cooking

appliances

Associated with respiratory symptoms

Carbon monoxide (CO) Heating* and cooking

appliances

Lethal at high levels, potential chronic

effects at low levels

Particulate matter (PM) Cooking , smoking ,

domestic activities

Reduced lung function and increased risk

of heart and respiratory disease

Environmental tobacco

smoke (ETS)

Cigarettes, cigars and pipes Lung cancer, chronic obstructive pulmonary

disease, asthma and reduced lung function

Allergens Moulds and house dust

mites

Worsening of symptoms of asthma;

causation of wheezing

Volatile organic compounds

(VOCs)

Cleaning products, paints et

al.

Respiratory tract irritation, possible effects

on asthmatics

FormaldehydeHair products, clothes, linen

and air fresheners, particle

board, plywood, and (MDF)

Associated with respiratory symptoms,

known carcinogen

*Unventilated mobile gas heaters allowed under part J of the Building Regulations.

(Composed using data from: Weschlar, 2009; PostNote 366, Shrubsole et al., 2012)


Detection: Can we rely on our senses?

Nose blindness: Even if you can sense it, do you stop noticing it, or ignore it?

Pollutant Type Sensory Characteristics

Particulate Matter PM10 and PM2.5

Visible (sometimes), smells (sometimes) Size, shape, mass, composition

Radon (222Rn) Colourless, odourless, tasteless

Nitrogen Dioxide (NO2) Brown, pungent irritating odour

Carbon monoxide (CO) Colourless, odourless, tasteless

Ozone (O3) Bluish, acrid smell, tightens breathing

Sulphur Dioxide (SO2) Colourless, pungent irritating odour

VOCs Generally colourless, smells (sometimes) and a variety of smells, not always unpleasant Source: http://activerain.com/


Monitoring: now and in the future

• Lack of sufficient data on indoor exposures

• Robust methods of analysis are required to ensure good IAQ.

• Dose response relationships

• Link to other dimensions: e.g. energy efficiency of building stock


Signs of poor IAQ: Advice to Occupants and Others

While poor IAQ can often manifest itself in ways that are undetectable (for example higher-than-safe CO concentrations), there are some warning signs to look out for, including: • musty, mouldy smells, • visible mould, • visible water build-up • stuffy atmosphere• health symptoms such as headache, dry/sore throat, dizziness and fatigue.

These symptoms often get ignored as seasonal allergies, but it may be the living environment that is to blame.

In some cases, poor IAQ can exacerbate respiratory problems like asthma and existing allergies.

A wide range of interventions are available, which can be classified according to the level at which they are effective: Interventions on the source of pollution

Interventions to the living environmentChanges in user behaviour


The complex and dynamic links arising from building envelope airtightening (without PPV) in the domestic stock and the impact on buildings, people and the wider environment

Shrubsole, C., Macmillan, A., Davies, M. and May, N. (2014). 100 Unintended consequences of policies to improve the energy efficiency of the UK housing stock. Indoor and Built Environment, 23(3), 340-352. Doi: 10.1177/1420326X14524586

Unintended consequences of policies to improve the energy efficiency of the UK housing stock.

http://dx.doi.org/10.1177/1420326X14524586


Unintended consequences of policies to improve the energy efficiency of the UK housing stock.


Conclusions

• Interventions (retrofitting) to the current building stock are needed in order to achieve carbon reduction targets.

• Policies to improve energy efficiency are having a big impact on IAQ.

• Interventions must be properly designed to avoid unintended consequences, including negative impacts on IAQ.

• Without adequate ventilation strategies, efficiency gains are made at the expense of human health.

• IAQ in buildings is a dynamic and complex issue that needs to be addressed along side other priorities.

• Public awareness of the issues of IAQ are rising and need to be addressed by building professionals.


Thank you for listening

Clive Shrubsole [email protected]