This rapid review provides an assessment of the contemporary health impacts arising from the household (indoor) and ambient (outdoor) air pollution exposure in low income (LIC) and lower-middle-income countries (LMICs), with a specific focus upon children aged under 5 years. The review synthesises findings of key systematic reviews, as well as international and national reports, supported by relevant case studies and illustrative data from primary epidemiological studies. It is not intended to be exhaustive but intends to highlight key areas of scientific knowledge and to identify notable gaps in the evidence base.
- Air pollution is recognised as the largest global environmental risk to health contributing to an estimated 7 million premature deaths worldwide each year (WHO, 2018). Globally, an estimated 93% of children live in environments where outdoor air pollution levels exceed World Health Organisation health-based air quality limit values, and more than one in four deaths of children aged under 5 years is directly or indirectly related to environmental risks (WHO, 2018).
- The WHO estimates that urban air pollution levels increased by 8% from 2008-13 and 97% of cities in LICs and LMICs with over 100,000 inhabitants exceed WHO air quality guidelines; thereby contributing to global health inequity (WHO, 2018). The evidence suggests that the early years are also the best time to invest in a child’s health, through action to improve their environment and reduce pollutant exposure (UN, 2017).
- Although overall levels of air pollution have declined in High-Income Countries (HICs) over the past 25 years, they have continued to increase in LIC and LMIC settings, notably the African, South-East Asia, Eastern Mediterranean and Western Pacific regions (WHO, 2018a). These contexts present the dual contemporary public health challenge of exposure to hazardous levels of both ambient and household air pollution, as a consequence of rapid industrialisation, urbanisation and ongoing reliance upon solid biomass fuels for basic domestic energy needs.
- Actions taken to reduce exposure to air pollution, particularly among children who are among the most vulnerable, also offers an opportunity to reduce health, social and gender inequalities and therefore improve lifelong health, wellbeing and economic productivity (RCP, 2016). Reducing air pollution can also mitigate harmful climate change impacts as many air pollutants are atmospheric warming agents (IPCC, 2018).
- Quantifying the association between pollutant exposure and distribution of specific disease outcomes, provides the best available information for policymakers and facilitates public communication concerning air pollution risks. However, there exists a paucity of high quality, large scale epidemiological studies conducted in LIC and LMIC contexts, resulting in gaps in our current knowledge (Gall et al., 2013; Sun and Zhang, 2018).
- Specific challenges include the availability of vital statistics, access to health information management systems, inconsistency in clinical coding practices and limited public health research infrastructure.
- Globally, using available health and demographic data sources it has been estimated that among children aged under 5 years in 2016 air pollution was responsible for 543,000 deaths, including 403,000 deaths from Acute Respiratory Lung Infections (ARLIs) and 37 million total Disability-Adjusted Life Years (DALYs) (WHO, 2018b). This reflects 9% of the total deaths arising from air pollution worldwide concentrated among LICs and LMICs in sub-Saharan Africa, south and south-east Asia and the western pacific regions.