Wednesday, April 05, 2017

The impact of smoke pollution on health in the 19th century

The good old days republicans want to return to.

Quantifying the impact of smoke pollution on health in the 19th century
Timothy Hatton 03 April 2017
Professor of Economics, Australian National University and University of Essex; and Research Fellow, CEPR

There is growing concern over the effects of atmospheric pollution on health. In 2016 WHO reported that 92% of the world’s population lives in in places where air pollution exceeds WHO limits (WHO 2016). It is calculated that outdoor air pollution accounts for three million deaths per year. And most of these deaths occur in low- and middle-income countries. The dense smog in China’s cities provides a sharp contrast to the relatively clean air of cities in the West.

But it was a different story a century ago. Coal-fired industrialisation in Europe spawned factories that belched black smoke, with little government regulation. Black smoke from these emissions was in the order of 50 times higher than today. Partly for this reason, urban centres had much higher mortality rates than rural areas. Indeed, there is evidence that the mortality gradient by industrial emissions was steeper in 19th century Britain than it is in China today (Hanlon and Tian 2015).

The more modest levels of atmospheric pollution in recent times, as reflected by concentrations of particulate matter and other pollutants, have been linked to premature death and to a variety of illnesses (Currie et al. 2013). Children are especially vulnerable as their lungs are still developing and they are prone to repeated infection.


We use regression analysis to control for household characteristics, including the social class of the head of the household and the number of siblings in the family. We also control for local population density, which has a strong negative effect on height. In the presence of these controls we find a significant negative relationship between coal intensity and adult height. This predicts a difference of nearly an inch (2cm) between the least and the most coal-intensive locations (10th vs 90th percentiles).


In order to identify the channels through which atmospheric pollution affected adult height during childhood, we turn to the mortality statistics. Respiratory diseases accounted for over 20% of all deaths of those aged under five. Death rates from respiratory causes varied widely between districts and they are strongly correlated with the death rates from all causes. Looking across districts, we find that our measure of coal intensity has a strong positive effect on the respiratory death rate.


From the birth cohorts of the 1890s to the those of the 1980s the heights of British men have increased by 2.75 inches (7cm) (Hatton and Bray 2010). So the decline in atmospheric pollution may have contributed significantly to improved health over the long run.

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