How do indoor environments affect health inequalities, inequities and injustice?

Health inequalities are a crucial aspect of public health and a pressing societal challenge. Access to healthy indoor spaces that are optimised to promote health should be seen as a fundamental right for all. This special issue is a starting point for the built-environment and public health communities to identify many existing inequities in order to improve methodological approaches, share vocabularies between disciplines, and create new knowledge necessary to create a safe and healthy indoor environments for all. Equitable design could translate into prioritising air quality improvements in the homes of people suffering from respiratory conditions, introducing inclusive design elements for disabled people, or providing energy retrofit subsidies to low-income, fuel-poor households.

Guest editors: Anna Mavrogianni & Marcella Ucci

There is compelling evidence that aspects of indoor environments, e.g. thermal, visual, acoustic conditions and air quality, can adversely affect health, but the role of indoor environments in health inequalities is less understood.

One fundamental question for public health and built-environment research is understanding how and to what extent indoor environments act as effect modifiers of structural inequalities or of other intermediary factors (e.g. outdoor conditions). This would then help address the other fundamental question: which pathways or levers pertaining indoor environments may be most effective at removing inequalities and delivering health equity?

The terms 'health inequality', 'health equity' and 'social determinants of health' deserve explanation.  Health inequality refers to mapping and understanding health disparities and their root causes. This can refer to differences in health status (e.g. life expectancy) but also in access to or quality of healthcare services, as well as differences in risky health behaviours (e.g. smoking) and, more broadly, differences in the wider 'social determinants of health'. The latter are deeply intertwined with the notion of health inequalities, framing health as a social phenomenon and emphasising how an individual's (or a group's) position in society plays a central role in health inequities. The most important structural stratifiers and their proxy indicators include: income, education, occupation, social class, gender and race/ethnicity (WHO Commission on the Social Determinants of Health). Several 'intermediary determinants' shape health outcomes-these include 'material circumstances', such as indoor (and outdoor) environmental conditions where people live and work. The term 'equity' refers to the principles that should guide the identification of potential 'fair' solutions.

The papers published in this special issue illustrate what can be achieved by integrating different methods (e.g. building stock modelling and focus groups) and data sources (e.g. Energy Performance Certificates and mental health data). Beyond their specific findings, the papers are a significant and novel contribution to the literature by providing a blueprint for the successful synthesis of methods and materials originally produced by different disciplines and sectors, and discussing the challenges and opportunities of their respective study designs and approaches.

Table of contents

Health inequalities and indoor environments: research challenges and priorities [editorial]
M. Ucci & A. Mavrogianni

Assessing retrofit policies for fuel-poor homes in London
M. C. Georgiadou, D. Greenwood, R. Schiano-Phan & F. Russo

IAQ and environmental health literacy: lived experiences of vulnerable people
C. Smith, A. Drinkwater, M. Modlich, D. van der Horst & R. Doherty

Linking housing, sociodemographic, environmental and mental health data at scale
P. Symonds, C. H. Simpson, G. Petrou, L. Ferguson, A. Mavrogianni & M. Davies

Measuring health inequities due to housing characteristics
K. Govertsen & M. Kane

A population-level framework to estimate unequal indoor heat and air-pollution exposure
R. Cole, C. Simpson, L. Ferguson, P. Symonds, J. Taylor, C. Heaviside, P. Murage, H. Macintyre, S. Hajat, A. Mavrogianni & M. Davies