Associations between exposure to air pollution and health
: a longitudinal study of middle-aged and older adults in China

  • Kai Hu

Student thesis: Doctoral Thesis (PhD)

Abstract

The Chinese population is ageing rapidly, and older Chinese adults (aged 45 and over) have spent a large proportion of their lives exposed to historically high levels of air pollution (AP). Previous studies suggest that there is a strong association between AP and individual health outcomes, but most of them have relied on cross-sectional measures of AP exposure and health, or both. These limit our understanding of how short-term, long-term, and cumulative exposures lead to changes in health outcomes. This PhD thesis addresses these gaps by investigating the longitudinal relationship between long-term and short-term exposure to AP and the health of older adults in China.

The thesis uses two kinds of survey data and two kinds of AP data. The Chinese Longitudinal Healthy Longevity Survey (CLHLS) 2011 and 2014 is linked with monitoring station AP data (used in chapter 4), and the China Health and Retirement Longitudinal Survey (CHARLS) 2011, 2013 and 2015, is linked with PM2.5 data that are retrieved from satellite data via remote sensing technology (used in chapters 5 and 6).

The main finding of the first empirical chapter using the CLHLS is that increased frailty incidence is associated with higher long-term exposure to AP rather than short-term fluctuations. The second empirical chapter using the CHARLS shows that exposure to PM2.5 over 15 years is associated with higher multimorbidity accumulation, and higher levels of PM2.5 are associated with a higher likelihood of membership to both respiratory and cardio-metabolic disease classes. The results of the third empirical chapter indicate that long-term exposure to PM2.5 is associated with poorer cognitive function, but different measures of long-term AP exposure are associated with different levels of cognitive decline. Overall, the three chapters indicate that long-term AP exposure has a negative association with elderly health, but that there may be some individual and contextual differences which are being conflated with these associations, and which deserve further exploration.

This thesis, therefore, makes several substantive and methodological contributions. First, I create a unique longitudinal dataset by linking historical AP data to representative longitudinal ageing surveys at the city level. Second, I investigate the associations of short-term and long-term exposure with health outcomes. Third, health outcomes of older adults are measured longitudinally using three comprehensive indicators that can reflect the complex relationship between AP and elderly health. The findings highlight the need to further consider cumulative and life-course AP exposure on elderly health at a smaller geographical scale.
Date of Award4 May 2022
Original languageEnglish
Awarding Institution
  • University of St Andrews
SupervisorKatherine Lisa Keenan (Supervisor), Joanna Mhairi Hale (Supervisor), Hill Kulu (Supervisor) & Tobias Borger (Supervisor)

Keywords

  • Air pollution
  • Elderly health
  • Frailty
  • Multimorbidity
  • Cognitive decline
  • Longitudinal analysis
  • China

Access Status

  • Full text embargoed until
  • 07 May 2025

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