This document summarizes a presentation on indoor air quality in new low-carbon buildings in the UK. It finds that energy efficiency improvements can have unintended consequences for indoor air quality. A cross-sectoral study of schools, hospitals, offices and apartments found indoor pollution levels exceeding guidelines, especially for PM and NO2. Measures like improved ventilation strategies and source control are needed to provide better indoor air quality while achieving energy efficiency.

1. Indoor air quality in new ‘low carbon’ buildings in the UK:
a cross sectoral analysis
IAQM Routes to Clean Air 2018
Dr Esfand Burman
UCL Institute for Environmental Design and Engineering
29 October 2018
Birmingham Conference and Events Centre

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• Energy performance gap in new buildings
• Unintended consequences of energy efficiency policies
• Cross sectoral study of IAQ
• Impact of ventilation strategies
• Outdoor vs indoor sources of pollution
• Key lessons learned
Outline

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Schools
Offices
Actual SpreadDesign Spread
Source: CarbonBuzz, 2016
Energy performance gap

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energy efficiency of
buildings
totalbuilding
performance shortfall
+
ieq
-
-
-B
R
energy efficiency
improvements
unintended IEQ consequences
Unintended consequences of energy efficiency policies

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Cross sectoral study of the performance gap
Schools
Hospitals
Apartment blocks
Offices

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Total Performance of Low Carbon Buildings in China and
the UK (TOP)

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PM concentration levels in London schools (predominantly naturally ventilated)
Source: Mumovic, D., Chatzidialakou, L., Willliams, J, Burman, E., 2018. Indoor Air Quality in London’s Schools, Greater London Authority.

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• Annual personal exposure to PM in the classrooms may be
higher than WHO 2010 guidelines.
• In most monitored classrooms, PM concentrations were
above daily guideline values.
• The difference in indoor PM levels between urban and
suburban schools was not statistically significant.
• Indoor PM10 concentrations during the occupied period
were consistently higher than outdoors.
PM Concentrations in London schools
Source: Mumovic, D., Chatzidialakou, L., Willliams, J, Burman, E., 2018. Indoor Air Quality in London’s Schools, Greater London Authority.

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Natural ventilation is the ‘default option’ in building design
Source: CIBSE Guide B2 (ventilation design), 2016

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Source: BSRIA, 2009

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PM2.5 concentrations in London: implications for
ventilation strategies
• EU legal limit (annual mean): 25 µg/m³
• WHO guideline limit (annual mean): 10 µg/m³

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PM2.5 standards in different countries
Source: Giannadaki et al., Environmental Health (2016) 15:88

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Estimation of health impact of PM2.5 concentrations
Source: Giannadaki et al., Environmental Health (2016) 15:88
Global premature mortality attributed to PM2.5 for the population <5 and >=30 years old

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Indoor Air Quality in a mechanically ventilated hospital
• Hospital in Bristol City Centre
• Inpatient services for surgery and
medicine (two operating theatres)
• Full mechanical ventilation (10-12 ACH)
• Sealed envelope

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Monitoring of indoor/outdoor air quality: CO₂
CO₂ concentration levels are usually lower than 750 ppm.
(IDA Class 1 Ventilation in BS EN 13779)

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Monitoring of indoor/outdoor air quality: PM2.5
Indoor concentration levels are significantly lower than outdoor.
(F9/HEPA filtration in air handling units)

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Monitoring of indoor/outdoor air quality: NO₂
Indoor NO₂ closely follows outdoor NO₂!
(Activated carbon filter or other measures required)
‘….Rack space is available and rack location identified for future
implementation of carbon filters or combination particle/carbon
filters………The mechanical system is sized to accommodate
the additional filters’. The Well Building Standard

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NO₂ concentrations in ‘low energy’ non-domestic case
studies
Office Hospital School
WHO guideline limits:
• Annual mean (chronic health effects): 40 µg/m³ (21 ppb)
• Hourly mean (acute health effects): 200 µg/m³ (105 ppb)

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PM2.5 concentrations in ‘low energy’ non-domestic case
studies
WHO guideline limits:
• Annual mean (chronic health effects): 10 µg/m³
• Daily mean (acute health effects): 25 µg/m³
Office Hospital School

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• New-build apartment blocks in East London (completed in 2015)
• Low air permeability: 2-3 m³/hr/m² at 50 Pa
• Mechanical Ventilation with Heat Recovery (MVHR)
• Low ACH (<1): indoor sources become more relevant!

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Source: Abadie and Wargocki, 2016. IEA EBC Annex 68 – Indoor Air Quality Design
and Control in Low-energy Residential Buildings, Subtask 1, Defining the metrics.

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Towards an integrated view of energy & IAQ
Source: Abadie and Wargocki, 2016. IEA EBC Annex 68 – Indoor Air Quality Design
and Control in Low-energy Residential Buildings, Subtask 1, Defining the metrics.

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Passive sampling of VOCs: heating season
VOC concentration
(µg/m³)
&
Air Change rates per
Hour for each zone
APT. 3 (Block A, 9th Floor) APT. 4 (Block B, Ground Floor) IEA EBC
Annex 68
Long
Term ELVLiving
room
Kitchen Sample
bedroom
Living
room
Kitchen Sample
bedroom
Benzene 1.3 1.0 1.2 1.5 2.1 1.6 0.2
Formaldehyde 29.25 26.87 29.53 21.23 31.35 27.44 9
Trichloroethylene <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 2
Styrene 1.5 2.2 3.0 0.8 0.7 1.7 30
Naphthalene 5.4 5.4 5.0 0.9 0.9 1.3 2
Toluene 2.7 2.9 3.1 2.2 2.6 2.4 250
Tetrachloroethylene 0.6 <0.6 <0.6 1.5 1.2 1.8 100
ACH (PFT
measurements)
0.50 0.52 0.76 1.02 1.14 0.6 n/a
Concentration levels of benzene and formaldehyde are significantly higher than long-term/chronic
exposure limit values (ELVs) in both apartments 3 years after completion!

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Internal sources of pollution
• Formaldehyde in all apartments 3 x ELVs
after 3 and a half years.
• Perceived wisdom of 2-3 years to off-gas is
questionable.
• Source control measures
• Boost ventilation mode on MVHR required to
be used?

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CLICK TO EDIT RUNNING TITLE STYLE Source: NRC Canada, 2005

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Minimum ACH achievable from installed MVHR
(ACH=0.1)
Maximum ACH achievable from installed MVHR
(ACH= 1)
MVHR commissioned flow rate (ACH= 0.6)
Doubling MVHR airflow could bring the concentration levels down to the chronic ELV
(Increase in energy use could be offset with higher heating efficiency or lighting efficacy)
IAQX

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Conclusions
• Major outdoor sources of pollution (PM2.5, NO₂)
in congested urban areas
• Source control measures critical (e.g. diesel and
petrol cars ban by 2040 in the UK)
• In the meantime, IAQ could be improved with more
effective ventilation strategies & protection measures
• Risk of high VOCs in airtight ‘low energy’ dwellings
(e.g. formaldehyde)
• Significance of source control (construction material
and MDF furniture)
• Enhanced ventilation and its implications for energy
efficiency

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Towards ‘total’ energy & environmental performance
Contact: esfand.burman@ucl.ac.uk
Source: Evening Standard, 8 May 2017