Dust to dust: How natural air pollution induces work accidents

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Air pollution can increase the risk of workplace injury. Workers breathing in harmful pollutants, including dust, are more likely to lose focus, experience fatigue and even become less patient. These factors can lead to a greater risk of getting hurt, from misusing a machine or by falling over. This column takes data from Spain, exploring how dust precipitation affects workplace accidents. The authors find evidence to show that a day of dust precipitation induces an average 1.2% increase in workplace accidents, compared with days with no dust. They argue that firms and policymakers should be wary of the risks posed by pollution, both directly to people’s health but also through increasing their risk of having an accident.


Occupational accidents are a major threat for European workers. Every year millions of people still suffer from their consequences. When thinking about how to avoid work accidents, improving air quality might not be the first thing that comes to mind. But a recent series of studies, focusing on different countries and pollutants, shows that air pollution contributes to accidents at work. Dirtier air means a more dangerous workplace, for many.

In this column, we review these recent findings and present additional evidence from natural pollution originating from Saharan dust. This analysis reveals interesting patterns across groups of workers. On average, one thousand workers die each day due to work accidents worldwide (World Bank, 2024). In the EU, at least 2.9 million workers suffered non-fatal accidents in 2021 (Eurostat 2024). Besides the suffering and distress for the victims, their families, and the local community, work accidents result in important societal losses due to medical costs, impaired human capital and foregone production. Only recently has the connection between air quality and workplace safety started to receive more attention. The evidence uncovers a serious risk factor for workers’ health.

 

Air quality and occupational safety

For decades now, economists have documented the negative effects of pollution in health (Graff Zivin and Neidell, 2013). More recently, researchers have paid increasing attention to the effects of air pollution on ‘non-health’ outcomes, such as physical and cognitive performance, risk behaviours and productivity (Aguilar-Gomez et al. 2022). The focus of this recent body of work is on the consequences of the sub-clinical physiological effects of air pollution. We refer to ‘sub-clinical effects’ as those that affect individuals which we consider, for the most part, to be in good health.

Exposure to air pollution affects a myriad of our bodily functions, even below the sickness threshold. Poor air quality affects our blood pressure, decreases our brains’ neurotransmitter production, reduces lung efficiency in exchanging oxygen for carbon dioxide, irritates our eyes, and affects our respiratory organs. The list goes on. These physiological changes mean that people experience tiredness, lack of focus, irritability and impatience. These afflictions are the channel we (and other economists) hypothesize can become risk factors in the workplace. Someone who is distracted, tired and/or impatient may be more at risk of having an accident, it seems.

Put differently, a worker exposed to air pollution can be more inattentive to risks, conduct hazardous tasks with less precision, or suffer from delayed reaction times to danger. For a machine operator adjusting settings on a high-speed assembly line, a momentary lapse in concentration can lead to entanglement or crush injuries from moving parts. A warehouse worker stocking shelves who misjudges the weight of a box risks a back strain. A waitress navigating a crowded restaurant at peak hour risks slipping and falling if they miss a spilled glass on the floor. Our hypothesis is that this type of deviation can be triggered by air pollution exposure and affect a broad spectrum of workers. From cafes to factories, dirty air can lead to lapses in concentration, and then to injuries.

Three other studies have looked at the causal effect of air pollution on work accidents in different settings. First, Lavy et al. 2019 look at the effect of NO2 concentrations on work accidents at construction sites in Israel. The headline finding is that a 10-ppb (parts per billion) increase in NO2 levels is associated with a 25% higher accident rate. This finding is, however, limited to a specific sector: construction. Second, Curci et al. 2024 focus on the effect of PM10 (particles with a diameter of 10 microns or less) and a composite measure of air pollution on work accident rates in Italy. In their main analysis, the authors use various heating rules in Italian regions to obtain pollution levels that change independently of other factors of work accidents. They find that a 1% increase in PM10 concentration leads to an increase of 0.23% in work accidents. Finally, Cabral and Dillender 2024 study the effect of PM2.5 (particles with a diameter of 2.5 microns or less) due to wildfire smoke on work accidents in Texas. They conclude that an additional day of smoke coverage increases work accidents by 2.8%. From Israel to Italy to the United States, pollution makes working more dangerous.

 

Evidence from dust precipitation events

In our latest working paper, we focus on the sensitivity of work accidents to an under-looked source of air pollution: dust precipitation. Dust precipitation is a phenomenon resulting from wind erosion over arid soil regions, such as the Sahara in Northern Africa, the Gobi Desert in East Asia, and the ‘North American Desert’ in the Southern United States and Northern Mexico. Dust storms in these regions launch vast amounts of fine dust particles to high altitudes. Wind can then transport these particles across long distances, sometimes reaching different continents. When dust precipitates to ground level, it adds up to the air pollution of receiving regions. Some important dust-receiving regions are the Mediterranean Basin, the Caribbean and the Pacific, though many other places are affected by this phenomenon, making dust ambient concentration a near world-wide environmental factor. Like with many other pollution sources, the effects of dust storms are felt far from where the gusts first blow.

We focus on Spain as a study case, and exploit dust precipitation as air pollution shocks which are unrelated to local economic activity. Our main analysis uses daily data of Spanish municipalities, with information about work accidents and local dust precipitation intensity. Our regression analysis compares seasonally adjusted work accident counts of the same municipality with similar weather conditions. This allows us to compare days with similar expected work accidents that differ only in the presence of dust precipitation. The idea here is to isolate the effect of dust on workplace risk.

We find that a day of dust precipitation induces an average 1.2% increase in work accidents, compared with days with no dust. On top of that, we show two additional sets of results. First, we examine the effect of dust precipitation on different groups of workers. Effects are significant for occupations of high and medium work-accident-risk (about 40% of the Spanish workforce).

The percentage increase of work accidents remains remarkably stable across occupations with a very different baseline risk of having a work accident. The overall burden of additional work accidents due to dust precipitation, however, is carried by the workers with the riskiest occupations. An additional day of dust pollution increases the accidents per worker more than 23 times more for the highest risk group than for the lowest. Effects of similar size are also present for both male and female workers. Finally, along the age dimension, we find statistically significant effects for prime-age workers – those who suffer the bulk of the work accidents. We find these effects are pervasive for workers of different wage levels, from the second to the fourth quintile of the income distribution. It doesn’t matter who you are or where you work. Dust poses a risk.

Second, we provide evidence for the mechanism behind the effect of dust precipitation on work accidents. Physical activities such as machine operations, or using manual tasks such as filling shelves, lifting furniture, binding, pulling, or screwing, as well as walking or running, make up the bulk of dust-related work accidents. Our evidence supports the causal path highlighted earlier about the origin of the effect of dust on work accidents.

 

Conclusion

Our research uncovers the role of dust pollution as a significant determinant of workplace safety. The findings reveal that dust precipitation elevates considerably the risk of accidents for workers across many occupations and income levels. This suggests that the safety of a broader spectrum of workers than previously recognised is vulnerable to air pollutants. These results underscore the importance of considering environmental risk factors in workplace safety protocols. The evidence advocates for a multidisciplinary approach to workplace safety, where environmental, occupational and public health policies converge to ensure safer working conditions for all.

Authors: Ismael Moreno Martinez, Benjamin Hattemer