Can workers avoid the damaging effects of high levels of air pollution? The answer, it appears, is overwhelmingly linked to socio-economic status.
Our recent study looks at how workers adjust their daily labor supply in response to increased concentrations of fine particulate matter known at PM 2.5, which originates, among other sources, from gasoline- and diesel-powered vehicles, as well as construction and industrial processes. We found that different types of workers respond differently to that highly pernicious form of pollution that can cause reduced cognitive function, disease and mortality.
We found that reductions in the labor supply on high-pollution days reflected workers’ decisions – as opposed to firms temporarily closing or reducing workers’ hours—and is consistent with workers reducing their labor supply to avoid air pollution exposure.
Income Matters Most
On average, workers in the bottom decile of income reduce their working hours 61% less than workers in the top income decile on days of high pollution. A 2019 survey in lower income neighborhoods of Mexico City found that nearly 95% of households reported that air pollution was a “problem” or “big problem.”
Workers can react to these threatening conditions by reducing their work hours on high pollution days and increasing their work hours in subsequent ones. But lower income workers have much less flexibility to do so. Indeed, on an average high pollution day in the peak pollution season at the beginning of the year, high-income workers reduce the hours that they work daily by an average of around an hour and 40 minutes, compared to just 48 minutes for a low-income worker.
Moreover, we found unequal responses to pollution based on other factors, such as job informality, but the differences are smaller than for income. For example, examining different categories like informal versus formal workers or employed versus self-employed workers doesn’t seem to change this basic dynamic. Nor does comparing workers who labor outdoors to those who labor indoors or considering government policy, like the closing of schools or public offices or the issuing of air quality alerts. Income is what matters most.
Interestingly, when high pollution is persistent over many consecutive days, both high- and low-income workers return to their normal work hours. When neither of the two preceding days had high levels of PM 2.5, they reduce their hours of labor in response to air contamination to the greatest degree. When there are more than two days in a row of high pollution, however, a limit to this adaptive behavior emerges. The reduction in hours worked eventually disappears, with lower-income workers more quickly making the transition to their usual work schedules.
Together, these findings suggest that lower-income workers are less able to adapt to environmental shocks. In addition, the findings indicate that workers will eventually accommodate to unrelenting pollution. If it were to increase so that its currently extreme levels became persistent, it is likely they would simply work their normal hours in a more polluted environment.
A Pollution Study with Implications for Social Policy
Our unique findings, using rich, high frequency data that provides for more subtlety and detail than weekly averages, have important implications for the implementation of social programs, not only in Mexico City, but in other large cities of the region, like Santiago, Lima and Bogota. Low-income workers in those cities – as well as many other developing ones – often lack publicly or privately funded sick leave. Measures that help such workers avoid steep drops in income when they avoid work on high pollution days could make a big difference in protecting their health.
Reducing Inequalities
Air pollution is not inevitable. But governments should at a minimum strive to curb peak pollution days when workers feel most at risk and reduce their working hours the most. They should also consider social programs that give lower-income workers greater flexibility to avoid work on dangerously unhealthy days. While many low-income workers already suffer from unequal access to health services, the right social programs could limit some of pollution’s disproportionate effects on them.
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