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Health effects of air pollution

Modelling the health impact of air pollution in Lambeth and Southwark

13 May 2021

Quantifying the health and economic impacts of NO2 and PM2.5

In brief

Extensive evidence has demonstrated that short-term and long-term exposure to air pollution has an adverse effect on people’s health. Short-term exposure to air pollutants has been linked to increased hospitalisations and exacerbations in diseases including, for example, Chronic Obstructive Pulmonary Disease (COPD) and asthma. Long-term exposure to air pollutants is related to the development of diseases including coronary heart disease (CHD), lung cancer and stroke. The main pollutants that impact health are particulate matter (PM) and Nitrogen dioxide (NO2).

This study uses a mathematical model to quantify the health and economic impacts of both NO2 and PM2.5 under different scenarios. The findings of this study build on the existing body of knowledge on this topic, including Public Health England’s ‘Estimation of costs to the NHS and social care due to the health impacts of air pollution’ (2018); Walton et al. (2019) ‘Health impact assessment of air pollution on asthma in London’; and Webber et al. (2020) ‘Modelling the long-term health impacts of changing exposure to NO2 and PM2.5 in London’.

Executive summary

Air pollution has an adverse effect on people’s health, both in the long- and short-term. We commissioned Health Lumen to quantify the impact of air pollution on the health of the populations of the London boroughs of Lambeth and Southwark. In these areas, the majority of air pollution comes from road traffic, but also from heating and construction emissions.

A number of policies have been put in place London-wide to reduce air pollution emissions and therefore prevent related impacts (for example ULEZ and BreatheLondon), as well as locally in Lambeth and Southwark. The findings of this study build on the existing body of knowledge on this topic by quantifying the impact of specific scenarios on air-pollution related health burden.

Aims of the report

  • Quantify the current annual morbidity, including disease incidence and NHS costs, attributable to air pollution in Lambeth and Southwark.
  • Quantify the long-term morbidity impacts, including reductions in disease incidence, NHS cost savings, and quality-adjusted life years (QALYs) gained, over the next 5 years’ time if Southwark and Lambeth were to meet the limits set by the WHO for PM5.
  • Quantify the long-term morbidity impacts over the next 5 years’ time in a ‘best case scenario’ where Lambeth and Southwark reach the NO2 and PM5 levels of the local authority with the lowest NO2 and PM2.5 levels in London (Havering).
  • Quantify the long-term morbidity impacts over the next 5 years’ time if Southwark and Lambeth reduce their NO2 and PM5 levels by the same percentage as it has been reduced in the COVID lockdown.

Annual disease incidence attributable to NO2 by year in Lambeth

Key findings

This study estimated the long-term health impacts (excluding disease exacerbations) of exposure to air pollution in Lambeth and Southwark from 2020 to 2024. Between 2020 and 2024, the total number of new disease cases attributable to NO2 and PM2.5 in Lambeth for diseases with an established evidence base is estimated to be 2,125. If including diseases with an emerging evidence base, this would rise to 4,730 cases. In Southwark in this same time period, the estimated new number of diseases attributable to NO2 and PM2.5 is 1,620 among diseases in the established evidence base, and 5,130 new cases when combined with emerging evidence.

Key findings from this study include:

  • For NO2 the largest number of cumulative cases of new disease avoided by 2024 would be 1,106 under the borough-specific COVID-19 ambitious scenario where NO2 is reduced by the same percentage as during the COVID lockdown for each borough. Of these cases, 155 are for child asthma, which has an established evidence base. The total health costs avoided by Lambeth and Southwark under this scenario would be £58,180 for child asthma alone and a total of £4,520,940 by 2024 when all evidence is included.
  • If both Lambeth and Southwark met the World Health Organization targets for PM5 (10 μg/m3annual mean) by 2024, an estimated total of 2,821 disease cases could be avoided, resulting in a reduction of £14,402,406 in cumulative healthcare costs (emerging and established evidence). For those diseases with an established evidence base only, we would see a reduction in 1,184 cases resulting in a reduction of £3,851,374 in cumulative healthcare costs across both boroughs.
  • A savings to the NHS of £14,402,406 if both Lambeth and Southwark met the World Health Organization targets for PM5, would be equivalent to annual salaries for 86 nurses over 5 years.[1]
  • The total costs avoided if Lambeth and Southwark reduced their air pollution (for NO2 and PM5 combined) to that of Havering (lowest London levels of NO2 and PM2.5) would be £6,713,061. Of this, £917,739 would be from diseases with the most established evidence base.

[1] This based on the Royal College of Nursing’s 2018 calculation of £33,384 average annual pay for nurses.

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