Part II: Impacts The health, comfort and energy consequences of poor indoor environmental quality for individuals and communities

Part II: ImpactsThe health, comfort and energy consequences of poor indoor environmental quality for individuals and communities

Homes and Communities Agency | ENEWorkshop – Overheating and indoor air quality in new homesTuesday 23rd June 2015, Future Business Centre, Peterborough

Dr Anna Mavrogianni | Lecturer in Sustainable Building and Urban DesignUCL Institute for Environmental Design and Engineering (IEDE), The Bartlett, University College London (UCL)

Homes and Communities Agency ENEWorkshop – Overheating and indoor air quality in new homesAnna Mavrogianni, UCL IEDE

In the context of the current global economic and climate crisis, there is a renewed interest in the linkage between indoor environmental quality, and •  comfort, •  energy, •  productivity, •  health and wellbeing.

Despite a notable progress in living standards and public health improvements in the last two centuries, a large proportion of the population in developed economies (predominantly low income households) is affected by: •  housing deficiencies, •  inadequate ventilation and poor indoor air quality, •  dampness and mould, •  overheating, •  overcrowding.

1 | Impacts of poor indoor environmental quality


Thermal discomfort is a negative impact in its own right. Over prolonged periods, thermal discomfort may lead to more serious health impacts for individuals. It can also cause sleep loss which may contribute to health risks for the person concerned and for others, as well as loss of work productivity.

For an individual, thermal comfort depends on: •  physical factors (air and mean radiant temperature,

air speed, relative humidity), •  behavioural factors (metabolic activity, clothing

levels), •  psychological factors (acclimatisation, expectations),

and •  social factors (social norms, habits, practices).

2 | Impacts of indoor overheating on thermal comfort


Human behaviour is an important determinant of summer thermal discomfort.


Living room operative temperature distribution for all window opening and lifestyle patterns for dwelling variants before and post full retrofit

(Mavrogianni et al. 2014, DOI: 10.1016/j.buildenv.2014.04.008)


A study of social housing residents in central London found that, although most follow general advice about hot weather, there are several areas where residents are poorly informed. Most notably there is a widespread misconception that opening windows can cool the home, as well as a lack of clarity about fan use.


Reasons for reluctance to open windows by social housing residents in South Islington (Kolm-Murray et al. 2013, www.climatesoutheast.org.uk/images/uploads/John_Kolm-Murray_231012.pdf)


Integrating adaptation and mitigation in building design is essential. Maladaptation to a warming climate, e.g. the uptake of air conditioning, will increase carbon emissions and operational costs.

5 | Impacts of indoor overheating on energy

Air conditioning use is currently very rare in England with less than 3% of households using fixed or portable air conditioning units during the summer months. However, according to current projections, air conditioning will be installed in half of all homes in England and Wales by 2050.


Extreme heat exposure can lead to hyperthermia, which may cause the symptoms of heat stress and, in particular: •  heat stroke, •  heat exhaustion, •  heat syncope and •  heat cramps.

6 | Impacts of indoor overheating on health

Among the most severely affected during a heatwave are: •  the elderly (above 65 years old), •  the chronically ill (in particular individuals suffering from cardiovascular,

cerebrovascular, renal and respiratory diseases), and •  the socially deprived population groups of the inner cities.


Excess seasonal mortality is generally defined as the short-term increase in the numbers of deaths above the average historic mortality figure recorded during an extreme weather episode in a given period and region.

7 | Impacts of indoor overheating on health

Excess mortality during the 2003 heatwave

Maximum central England temperature and daily mortality, England and Wales,July and August 2003

(Johnson et al. 2005, www.eurosurveillance.org/ViewArticle.aspx?ArticleId=558)


High temperatures can have detrimental effects on cognitive performance, work productivity, and health and safety. •  It is estimated that approximately a 7% increase in work productivity is present

in a workplace maintained at the population-average neutral temperature of between 20–24°C.

•  It is also estimated that productivity is affected after about one hour of moderate physical work in temperatures above 32°C.

•  Reductions in academic performance as great as 30% have been recorded when 9-10-year old children were exposed to classroom temperatures of 27 °C and 30 °C in comparison with 20 °C.

•  Further research is needed to link sleep deprivation due to overheating at home with potential work productivity losses and work accidents.

8 | Impacts of indoor overheating on productivity

Lundgren et al. 2013, DOI: 10.2486/indhealth.2012-0089


Indoor air pollution has a range of effects on health.

9 | Impacts of poor indoor air quality on health

Pollutant Source Health impact

PM Cooking, smoking, outdoors Respiratory and cardiovascular illnesses

SO2 Cooking, outdoors Impairment of respiratory function

NO2 Cooking, outdoors Lung irritation

CO Cooking, water heater, outdoors Toxic and fatal > 700 ppm

O3 Outdoors Asthma and allergic triggers

VOCs Building materials, paint Eye irritation, some are carcinogenic

Radon Earth and rocks Lung cancer

Biological air pollutants Pets, humans, dust mites Breathing problems


These effects are not uniformly distributed across the population: •  Adults and children with lung or heart conditions (usually older people) are at

increased risk of becoming ill and needing treatment. •  Low-income households are more likely to suffer from poor indoor air quality

than high-income households.

10 | Impacts of poor indoor air quality on health

Cooking PM2.5 concentrations for current and fully retrofitted scenarios, and across income and tenure groups (Shrubsole et al. 2015, DOI: 10.1080/17512549.2015.1014844


Thank you | Any questions?