As lockdowns to contain the spread of COVID-19 shut down shops and restaurants, force most to stay home from school and workplaces, and generally reduce economic activity, there is no doubt a lot less fuel is being burned. What impact has this had on emissions and pollution? A new study quantifies the effects of these unprecedented changes through two channels: fewer people driving and less electricity being used.
Using daily cell phone data from February through April to measure changes in mobility—and by extension, vehicle miles traveled—as well hourly electricity data, Harris Public Policy Assistant Professor Steve Cicala and his co-authors found a 40 percent decline in driving and a 6 percent decline in electricity use. That decline means fewer emissions that impact public health, shorten lives, and lead to climate change. Altogether, they estimate there have been approximately 360 fewer deaths per month from particulate pollution in the United States during the COVID-19 pandemic. As a means of comparison, particulate pollution generated by driving and electricity production usually contributes to about 1,500 deaths in a normal month.
It is notoriously difficult to count pandemic deaths during the midst of a crisis, so epidemiologists often supplement official tallies with estimates of additional deaths that may ultimately be attributable to the disease. However, says Cicala, “It has been difficult to pin down the exact number of COVID-19 deaths, in part because there are other drivers of respiratory mortality that have been affected during the recent crisis. Pollution is one of those drivers. Accounting for the impact of pollution on mortality suggests that COVID-19 deaths are actually slightly higher than what you would calculate from looking at the change in overall respiratory mortality.”
Less driving and electricity use also means fewer emissions that cause climate change. The researchers found that social distancing measures resulted in about 46 million metric tons fewer CO2 emissions per month— that’s 19 percent of the 242 million metric tons that are typically emitted monthly from driving and using electricity.
Social distancing was not evenly distributed across the country as some states and cities issued stay-at-home policies for longer periods than others. As a result, the impact from less driving and electricity use varied widely, with the greatest reductions in deaths primarily seen in cities because a larger population drives more.
Social distancing in California accounted for about a third of U.S. reductions in deaths from driving-related air pollution, with Los Angeles alone contributing 20 percent of the national total. New York accounted for about 10 percent of the national total. New Jersey, Florida, and Illinois also saw large reductions in respiratory deaths linked to driving. Meanwhile, the Southeast and Midwest saw the largest reductions in deaths from the drop in electricity demand.
“Our findings also demonstrate the degree to which less reliance on fossil fuels yields benefits to our health and to the climate,” Cicala says. “Electricity consumption has been declining over the last decade. If that continues, and remote work becomes more common as the world recovers from COVID-19, this is perhaps a window into longer-term health improvements from less pollution.”
Cicala’s co-authors include Stephen P. Holland from the University of North Carolina at Greensboro, Erin T. Mansur from Dartmouth University, Nicholas Z. Muller from Carnegie Mellon University, and Andrew J. Yates from the University of North Carolina at Chapel Hill.