Long-term exposure to pollutants and mental health

• In Event: Environmental Determinants of Health: Evidence from Air, Water, and Heat

Abstract

Exposures to pollutants like particulate matter are known to have negative impacts on our cognitive and mental health. Studies show that particulate matter (PM) exposure is significantly associated with various psychiatric disorders including depression (Bhui et al., 2023; Park, 2024). In this paper, we aim to examine the impact of long-term exposure to air pollution on depression and other cognitive health measures among older adults in India.

We use the Longitudinal Aging Study in India (LASI) 2017-18, which is a nationally representative data set that contains various self-reports and objective measures of health including depression and measures of cognitive health. In the survey, about 40% of the respondents reported that they have never moved since birth.

Using this sample of respondents who never moved, we estimate the impact of long term air pollutant exposure on mental health among the elderly.  We identified several states that consistently had high and low concentrations of PM2.5 from 1998 to 2020 using the data on fine particulate matter (PM 2.5) and findings from research (Guttikunda and KA, 2022). Some states had a level of PM2.5 that is at or below the World Health Organization’s annual guideline of 5 µg/m3 whereas other states consistently had PM 2.5 level of above 40µg/m3 (India’s national average). Compared to 1998, PM 2.5 concentrations (annual average) increased steadily across states. Even though the overall level increased, the leading states with PM2.5 concentrations remain nearly the same (or got worse over time) and vice versa.  

We created an indicator variable that equals 1 for states that had consistently high PM2.5 concentration and 0 for states that had steadily low PM 2.5 concentrations. We also created an indicator variable for those who are born in the winter (Dec-Feb) where more exposure to pollution is expected.  We estimate a fixed effects model on depression (both subjective and objective measures) and other cognitive health outcomes controlling for sociodemographic characteristics (age, educational attainment, gender, marital status, whether you live in rural area, employment status, annual earnings, religion, and mother tongue), health care utilization and insurance coverage, and state fixed effects.

We found that respondents who lived (and never moved) in high PM states and born during winter were significantly more likely than those who lived in low PM states to have higher CESD scores. Furthermore, those individuals who were born in the winter month and lived in Northern states (areas that have higher PM concentration than other areas) are more likely to recall 3 or less words out of 10 words correctly.

 

Author

• Anna Choi, Sejong University
  Presenting Author