Businesses invest a great deal of time and money in interventions that claim to increase workers’ productivity through on-the-job training, new protocols, advice from consultants, and so on. Recent research suggests that there’s a surprising input into productivity that no one ever thinks about: clean air.
We all know that air pollution is bad for our health, and researchers continue to find evidence of pollution’s negative effects. But recent research has gone further, starting to catalog how pollution might affect our productivity. Several studies have demonstrated that pollution reduces the output of both farm workers and factory workers. When pollution levels — namely outdoor ozone and indoor particulate matter — increase, physical laborers can’t help but slow down.
But what about the productivity of indoor workers who sit in front of a computer all day? We wanted to know whether those workers were hurt by pollution too. To find out, we investigated the effect of air pollution on call-center workers at Ctrip, China’s largest travel agency. Workers at Ctrip are knowledge workers; they spend their day not in a factory or on a farm, but handling customers’ phone calls. If they’re affected by pollution, then we might all be vulnerable.
Several aspects of the firm’s operations allowed us to credibly isolate the effect of pollution on productivity. First, the firm keeps detailed records on the productivity of each worker: completed calls each day, length of breaks, time logged in. Ctrip has multiple call centers, and all calls are routed through a central system, so overall workflow is not determined by local pollution. And since Ctrip’s clients call them from locations throughout China, we were able to separate out the effects of pollution on worker productivity from the effects of local pollution on the demand for travel services.
In analyzing Ctrip’s personnel records, we found a surprisingly robust relationship between daily air pollution levels and worker productivity. On average, a 10-unit increase in the Air Quality Index (AQI) led to a 0.35% decline in the number of calls handled by a Ctrip worker. That finding suggests that workers are 5%–6% more productive when air pollution levels are rated as good by the Environmental Protection Agency (AQI of 0–50) versus when they are rated as unhealthy (AQI of 150–200). To our knowledge, our study is the first to document the impact of air pollution on white-collar work.
What’s more, we found that pollution affected Ctrip workers’ productivity even when pollution levels were relatively low. We found significant productivity effects at pollution levels commonly seen in major metropolitan areas across the United States (100–150 AQI). For example, in 2014 Los Angeles experienced 13 days with AQI greater than 150, and Phoenix experienced 33 such days, with nearly half those days exceeding an AQI of 200. These levels are even more common throughout Europe, where air quality standards are generally more lenient.
While more work needs to be done to pin down the mechanism at play here, we do know something about how pollution diminishes cognitive function. Particulate matter is small enough to be absorbed into the bloodstream, and even travels along the axons of the olfactory and trigeminal nerves into the central nervous system (CNS), where it can become embedded deep within the brain stem. This, in turn, can cause inflammation of the CNS, cortical stress, and cerebrovascular damage. Greater exposure to fine particles is associated with lower intelligence and diminished performance over a range of cognitive domains. If the negative impact on productivity that we found in our research are the result of diminished cognitive function, it could mean that the negative impact of pollution on productivity may be greatest in higher-skilled jobs.
All of this might really matter for the economy as a whole. For policy makers, the evidence changes the cost-benefit analysis of environmental regulation and suggests that prioritizing industrial expansion over environmental protection may actually undermine economic growth. Indeed, a quick back-of-the-envelope calculation suggests that for Shanghai, air pollution is costing its service sector billions of dollars each year in lost productivity.
For businesses, this suggests that installing air filters may bring surprising benefits; HEPA air filters can remove much of the pollution that, we’ve shown, hampers productivity. That said, it’s not clear that air filters can completely remove these pollutants. Moreover, while businesses can invest in a good air filtration system, they can’t lower the pollution levels their workers face when they go home. The fact that there is only so much an individual firm can do should not be surprising. The air we breathe is the epitome of a shared resource, and air pollution recognizes no corporate or political boundaries. Therefore, air pollution can only be efficiently controlled by policy that extends beyond the borders of a single firm.
For everyone else, our findings are a reminder that our own productivity isn’t completely in our control. Instead, it hinges partly on complicated environmental factors like pollution. If your productivity seems a little off one day, the answer might be partly in the air.