Air pollution hurts us in ways we typically do not think of

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Readers will not be surprised to learn that air pollution adversely affects our well-being in a variety of ways. For instance, we have known for quite a while that air pollution causes respiratory illness and cardiovascular disease. More recently, evidence has appeared that air pollution negatively affects the productivity of workers and the number of hours they work. In addition, high levels of air pollution have been associated with criminal activity and with unethical behavior.

The productivity losses from a particular kind of air pollution, namely, the presence of fine particulate matter that is 2.5 microns or less in width or PM2.5 (there are 25,000 microns in an inch) are noteworthy. Evidence has accumulated that PM2.5 adversely influences even relatively undemanding jobs such as work in call centers and that it plays a role in reducing the standardized test scores of high school students.

The above insalubrious impacts of air pollution notwithstanding, readers probably do not think of air pollution and sleeplessness as being causally connected. However, interesting new research by Anthony Heyes and Mingying Zhu shows that, in fact, they are. These researchers focus on the 19 largest cities in China and construct an unusual measure of sleeplessness. Specifically, this measure utilizes the nightly frequency with which the Chinese characters meaning “cannot sleep,” “sleepless,” etc., are used on the widely known social media site Weibo. Then, using econometric techniques, they show that there is a definite relationship between their constructed measure of sleeplessness and same-day local air quality in the different cities.

How important is this relationship quantitatively? The research shows that a one standard deviation in the air quality index (a measure of air pollution) leads to an 11.6 percent increase in sleeplessness. In addition, when attention is restricted to only PM2.5, the corresponding increase in sleeplessness is 12.6 percent.

Sleep is clearly a key contributor to human well-being and hence all sleep disturbances are likely to have one or more adverse impacts. That said, if air pollution in a city detrimentally affects how well the residents of this city sleep, then this means that there is an unaccounted social cost of air pollution that policymakers need to ponder when formulating air pollution control regulations.

Is there a causal relationship between air pollution and road safety? Exciting new research by Lutz Sager sheds light on this question by estimating the impact of an increase in air pollution, measured as the daily average concentration of PM2.5, on the number of vehicles that are involved in road traffic accidents in 153 regions in the United Kingdom between 2009 and 2014. This estimation exercise is tricky because road traffic itself is a major source of air pollution.

Therefore, to plausibly identify the impact of interest, this research uses the notion of a temperature inversion to account for variations in air pollution levels. A temperature inversion is a meteorological phenomenon in which atmospheric temperature profiles deviate from what is standard. So, on most days, when temperature decreases with altitude, pollutants generally rise and then scatter. However, during an inversion incident, the temperature profile is inverted, meaning that warmer air at higher altitudes traps pollutants close to the ground.

The results demonstrate that there exists a positive and statistically significant effect of air pollution on the number of vehicles involved in traffic accidents. Quantitatively speaking, this means that a 1 microgram per cubic meter increase in the average concentration of PM2.5 leads to a 0.4 percent increase in the number of vehicles involved in accidents. If we were to apply this finding to the city of London, then a one standard deviation reduction in PM2.5 for a single day would lower accident costs by about £500,000 or US $690,000.

Our current approach to figuring out the social costs of air pollution are generally focused on the health implications of this pollution. However, new research clearly shows that by omitting the effect that air pollution has on traffic accidents, we may, like the case of sleeplessness, be underestimating the true cost of air pollution to society.

Given the research findings delineated here, it is time for policymakers to look comprehensively at the societal costs of air pollution. Otherwise, our many pollution control regulations will only be tackling a part of the Hydra-headed beast that air pollution appears to be.

Batabyal is the Arthur J. Gosnell professor of economics at the Rochester Institute of Technology but these views are his own.