Analysis of inequalities in personal exposure to PM2.5: A modelling study for the Greater London school-aged population

Exposure to air pollution can lead to negative health impacts, with children highly susceptible due to their immature immune and lung systems. Childhood exposure may vary by socio-economic status (SES) due to differences in both outdoor and indoor air pollution levels, the latter of which depends on, for example, building quality, overcrowding and occupant behaviours; however, exposure estimates typically rely on the outdoor component only. Quantifying population exposure across SES requires accounting for variations in time-activity patterns, outdoor air pollution concentrations, and concentrations in indoor microenvironments that account for pollution-generating occupant behaviours and building characteristics. Here, we present a model that estimates personal exposure to PM2.5 for ~1.3 million children aged 4–16 years old in the Greater London region from different income groups. The model combines 1) A national time-activity database, which gives the percentage of each group in different residential and non-residential microenvironments throughout a typical day; 2) Distributions of modelled outdoor PM2.5 concentrations; 3) Detailed estimates of domestic indoor concentrations for different housing and occupant typologies from the building physics model, EnergyPlus, and; 4) Non-domestic concentrations derived from a mass-balance approach. The results show differences in personal exposure across socio-economic groups for children, where the median daily exposure across all scenarios (winter/summer and weekends/weekdays) is 17.2 μg/m3 (95%CIs: 12.1 μg/m3–41.2 μg/m3) for children from households in the lowest income quintile versus 14.5 μg/m3 (95%CIs: 11.5 μg/m3 – 27.9 μg/m3) for those in the highest income quintile. Though those from lower-income homes generally fare worse, approximately 57 % of London's school-aged population across all income groups, equivalent to 761,976 children, have a median daily exposure which exceeds guideline 24-h limits set by the World Health Organisation. The findings suggest residential indoor sources of PM2.5 are a large contributor to personal exposure for school children in London. Interventions to reduce indoor exposure in the home (for example, via the maintenance of kitchen extract ventilation and transition to cleaner cooking fuels) should therefore be prioritised along with the continued mitigation of outdoor sources in Greater London

Setting the standard: The acceptability of kitchen ventilation for the English housing stock

Exposure to particulate matter with diameter ≤2.5 μm (PM2.5) is associated with an elevated risk of adverse health effects and cooking is a primary source of PM2.5 in non-smoking households. Therefore, it is important to investigate PM2.5 concentrations that might be found in domestic kitchens, and the appropriate ventilation mechanisms to reduce them.Uncertainty in daily mean PM2.5 concentrations in English kitchens is predicted using a statistical model and stochastic simulation. A worst-case heating season scenario is considered where 3 meals are cooked per day and fresh air is provided by infiltration and fans.The model predicts that >98% of English houses are too airtight to dilute PM2.5 emissions solely by infiltration so that daily mean concentrations in kitchens are below the WHO guideline of 25 μg/m3. Therefore, controlled ventilation is required in all kitchens. Ventilation strategies prescribed by English Building Regulations and ASHRAE 62.2 are found to be adequate for [less than] 12% and 75% of houses, respectively, when applied during cooking. Continuing to ventilate for a further 10 minutes has a significant effect when using an intermittent strategy, increasing the centiles of compliant houses to 46% and >98%, respectively. A cooker hood is the most effective ventilation strategy when used during cooking plus 10 minutes. Standards should be amended to incorporate required combinations of airflow rates and capture efficiencies. A hood with a capture efficiency of 50% requires airflow rates of 52 l/s and 90 l/s for PM2.5 concentrations to remain below WHO guidelines in 75% and 98% of houses, respectively

Analysis of inequalities in personal exposure to PM2.5: A modelling study for the greater London school-aged population

Exposure to air pollution can lead to negative health impacts, with children highly susceptible due to their immature immune and lung systems. Childhood exposure may vary by socio-economic status (SES) due to differences in both outdoor and indoor air pollution levels, the latter of which depends on, for example, building quality, overcrowding and occupant behaviours; however, exposure estimates typically rely on the outdoor component only. Quantifying population exposure across SES requires accounting for variations in time-activity patterns, outdoor air pollution concentrations, and concentrations in indoor microenvironments that account for pollution-generating occupant behaviours and building characteristics. Here, we present a model that estimates personal exposure to PM2.5 for ~1.3 million children aged 4–16 years old in the Greater London region from different income groups. The model combines 1) A national time-activity database, which gives the percentage of each group in different residential and non-residential microenvironments throughout a typical day; 2) Distributions of modelled outdoor PM2.5 concentrations; 3) Detailed estimates of domestic indoor concentrations for different housing and occupant typologies from the building physics model, EnergyPlus, and; 4) Non-domestic concentrations derived from a mass-balance approach. The results show differences in personal exposure across socio-economic groups for children, where the median daily exposure across all scenarios (winter/summer and weekends/weekdays) is 17.2 μg/m3 (95%CIs: 12.1 μg/m3–41.2 μg/m3) for children from households in the lowest income quintile versus 14.5 μg/m3 (95%CIs: 11.5 μg/m3 – 27.9 μg/m3) for those in the highest income quintile. Though those from lower-income homes generally fare worse, approximately 57 % of London's school-aged population across all income groups, equivalent to 761,976 children, have a median daily exposure which exceeds guideline 24-h limits set by the World Health Organisation. The findings suggest residential indoor sources of PM2.5 are a large contributor to personal exposure for school children in London. Interventions to reduce indoor exposure in the home (for example, via the maintenance of kitchen extract ventilation and transition to cleaner cooking fuels) should therefore be prioritised along with the continued mitigation of outdoor sources in Greater London.Peer reviewe

Indoor Air Quality

This is a report from the Air Quality Expert Group to the Department for Environment, Food and Rural Affairs; Scottish Government; Welsh Government; and Department of Agriculture, Environment and Rural Affairs in Northern Ireland, on indoor air quality in the UK. The information contained within this report represents a review of the understanding and evidence available at the time of writing

Health effects of indoor air quality on children and young people

Air pollution is the environmental public health problem of our time. The United Nations Convention on the Rights of the Child sets out clear guidance to protecting the rights of children and young people, including a child's right to the best possible health (Article 24) and the right to a good standard of living. Unicef also consider that clean air is a right for all children. The UK Royal Medical Colleges vigorously advocate for a healthy environment at the population level and in local communities, especially where socio-economic circumstances limit the choice of where people can live, and which school children attend. Despite substantial progress in understanding outdoor air pollution, the potential risk to health, especially that of children and young people, from the indoor air has been largely overlooked, yet in modern times, the indoor environment has never been more important as lockdown with the Covi-19 virus pandemic has shown us. Here we provide an abridged version of the RCPCH/RCP Report The inside story: Health effects of indoor air quality on children and young people but without the section on recommendations. The full Report along with recommendations, released on 28 January 2020, can be accessed at https://www.rcpch.ac.uk/resources/inside-story-health-effects-indoor-air-quality-children-young-people. While we recognise that some aspects of this commentary are UK specific, much of the content has wide implication

Developing a programme theory for a transdisciplinary research collaboration: Complex Urban Systems for Sustainability and Health

Background: Environmental improvement is a priority for urban sustainability and health and achieving it requires transformative change in cities. An approach to achieving such change is to bring together researchers, decision-makers, and public groups in the creation of research and use of scientific evidence. Methods: This article describes the development of a programme theory for Complex Urban Systems for Sustainability and Health (CUSSH), a four-year Wellcome-funded research collaboration which aims to improve capacity to guide transformational health and environmental changes in cities. Results: Drawing on ideas about complex systems, programme evaluation, and transdisciplinary learning, we describe how the programme is understood to “work” in terms of its anticipated processes and resulting changes. The programme theory describes a chain of outputs that ultimately leads to improvement in city sustainability and health (described in an ‘action model’), and the kinds of changes that we expect CUSSH should lead to in people, processes, policies, practices, and research (described in a ‘change model’). Conclusions: Our paper adds to a growing body of research on the process of developing a comprehensive understanding of a transdisciplinary, multiagency, multi-context programme. The programme theory was developed collaboratively over two years. It involved a participatory process to ensure that a broad range of perspectives were included, to contribute to shared understanding across a multidisciplinary team. Examining our approach allowed an appreciation of the benefits and challenges of developing a programme theory for a complex, transdisciplinary research collaboration. Benefits included the development of teamworking and shared understanding and the use of programme theory in guiding evaluation. Challenges included changing membership within a large group, reaching agreement on what the theory would be ‘about’, and the inherent unpredictability of complex initiatives

Housing, Indoor Air Pollution, and Health in High-Income Countries

Despite the overwhelming evidence that living in poor-quality housing and built environments are significant contributors to public health problems, housing issues persist and represent a considerable societal and economic burden worldwide. The complex interaction between multiple behavioral, lifestyle, and environmental factors influencing health throughout the “life-course” (i.e., from childhood to adulthood) in high-income countries has limited the ability to develop more salutogenic housing interventions. The resultant, usually negative, health outcomes depend on many specific housing factors including housing quality and standards, affordability, overcrowding, the type of tenure and property. The immediate outdoor environment also plays an important role in health and wellbeing at the population level, which includes air (indoor and outdoor), noise pollution and the quality of accessible natural environments. These exposures are particularly important for more vulnerable populations, such as the elderly or infirm, and those living in insecure accommodation or in fuel poverty (i.e., being unable to heat the home adequately). Being homeless also is associated with increased risks in a number of health problems. Investigating pathways to protecting health and wellbeing has led to a range of studies examining the potential benefits resulting from accessing more natural environments, more sustainable communities, and housing interventions such as “green construction” techniques. Built environment interventions focusing on the provision of adequate housing designs that incorporate a “life-course” approach, affordable and environmentally sustainable homes, and urban regeneration along with active community engagement, appear capable of improving the overall physical and mental health of residents. While some interventions have resulted in improved public health outcomes in more high-income countries, others have led to a range of unintended consequences that can adversely affect residents’ health and wellbeing. Furthering understanding into four interrelated factors such as housing-specific issues, the immediate environment and housing, vulnerable populations, and natural spaces and sustainable communities can help to inform the development of future interventions