The bright side of Covid restrictions: lives saved from less pollution
A new study estimates some 360 fewer monthly deaths, mostly from reductions in vehicle emissions.
One of the few silver linings of the Covid-19 pandemic and its resulting economic turmoil has been the environmental benefits of shutting down cities. The massive reduction in greenhouse gas emissions is great for the long-term fight against climate change. But improved air quality has a more immediate impact as well, in terms of saving lives.
A new analysis puts a number to that health outcome for the U.S., estimating that more than 360 monthly deaths have been avoided during the outbreak — the result of enormous dips in vehicle pollution and more moderate dips in electricity-related emissions. The research, published this week in an NBER working paper, comes from a group of economists and public policy scholars.
The group concludes:
In this state of the world as observed in early April 2020, power demand is only marginally affected, whereas personal travel declines appreciably. The paper shows significant local health benefits from this adjustment.
To conduct their analysis, the researchers first collected data on vehicle use and electricity consumption during the Covid outbreak, focusing on the period of February to April 2020. They then compared these recent trends against historical trends from years past. They found a 40 percent decline in (non-truck) vehicle miles and a 6 percent dip in power use.
With that baseline insight, the researchers then modeled the reduction in deaths from pollution, taking into account local demographic and environmental factors. During a typical month in the past, the U.S. averaged about 1,525 premature deaths attributable to pollution. The model estimated that 1,162 pollution-related deaths occurred during Covid interventions — 363 lives saved over the norm.
The bulk of the benefit came from fewer people driving through cities. The analysis estimated that Covid interventions spared 315 lives from vehicle pollution (primarily through reductions in nitrogen oxide). Another 49 deaths were prevented through the reduction of electricity-related emissions (primarily sulfur dioxide).
With respect to the impact of vehicle emissions in particular, the estimates varied widely by city. The model found the greatest reduction in expected deaths in car- and smog-heavy Los Angeles (77), with nearby Santa Ana (8) also high on the list. New York City ranked second in lives spared (26), followed by Chicago (12). Here’s the top 10:
A similar list isn’t possible for the reductions in deaths from electricity generation, because power grids don’t map cleanly onto city boundaries. But there was still a lot of variation by region. The model found the greatest reduction in deaths in the Southeast (13) and Midwest (12) utility markets, potentially reflecting the relatively greater coal-reliance of the electricity grids in these regions.
The study’s biggest limitation is that the emissions reductions are extrapolated from historical emission rates, not direct measurements. That said, if anything, the analysis understates the number of lives saved through emissions reductions, since it’s based on historical mortality rates that don’t take into account the fact that pollution has been found to exacerbate Covid.
The analysis isn’t meant to minimize the impact of Covid in any way, but it does provide a small form of solace at a tough moment, and it also helps bring the health benefits of reducing fossil fuel reliance into clearer, more personal focus. Such work has implications for the future of urban development, both in the short-term recovery period and over a longer horizon.
With respect to mobility, the research underscores the need for cities to focus attention on avoiding a post-pandemic surge in traffic congestion. As the economy reopens, many city residents will flock to their cars out of fear of using public transportation, leading in turn to more deaths from vehicle pollution (as well as collisions). Efforts to restore confidence in transit and expand alternatives such as cycling and safe pedestrian space will be critical — with such initiatives potentially paid for by a pollution surcharge on non-electric vehicles.
With respect to electricity, the work shows there’s still a ways to go, given that it took a total economic shutdown to cut power use by 6 percent. Cities should double down on building techniques that reduce energy needs, such as Passive House. Building on significant advances in renewable power, they must also find ways not only to generate and store clean power but to deploy it during peak periods, when the electricity grid still relies on fossil fuels. That strain only stands to increase as more electric vehicles join the mix and as more cities move away from natural gas.
There haven’t been many silver linings of this crisis, which makes it all the more important to take the ones that emerge as opportunities for the future.
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