Commentary: Lockdown didn’t cause lower ozone levels

By David T. Stevenson

High levels of ground-level ozone heighten symptoms for people with respiratory ailments, such as asthma and chronic obstructive pulmonary disease, and can result in more hospitalizations. Of seven key air pollutants, only ozone measures higher than the national air quality standard in most urban areas across the country.

David T. Stevenson

It was expected that the COVID-19 lockdowns would greatly reduce ozone. Contrary to statements based on anecdotal evidence by Sen. Thomas R. Carper (“Telework could lead to environmental solutions,” Aug. 8), actual U.S. Environmental Protection Agency air quality data from 16 counties surrounding Philadelphia, including New Castle County, showed that didn’t happen.

The lockdowns did work to reduce human activity. Delaware Department of Transportation reports that traffic on I-95 near Wilmington was down in late March and early April. The American Petroleum Institute estimated refinery operation fell 20%. Electricity use was also down.

Ozone is not emitted directly, but is created in the presence of nitrogen oxides and volatile organic compounds and reaches health-harming levels on warm, sunny days. Measured levels of nitrogen oxide fell by about half, but that by itself didn’t help air quality much. However, based on modeling, the reduction should have resulted in lower ozone. What happened?

The EPA estimates 70% of ozone precursors come from natural sources such as plants, insects and animals, wildfires, soil, lightning and volcanoes. There has been a long-standing debate about the relative importance of natural versus manmade pollutants in setting standards, thus the development of computer models. It appears the computer models are simply wrong.

Ozone levels have decreased 35% since 1980 by reducing manmade precursor sources. It appears we may be reaching the point of diminishing returns for regulatory actions because of the growing influence of uncontrollable natural sources. This has important consequences for setting air quality standards, and the ozone standards are being reviewed this year.

Tight regulatory permitting can add cost to the products we use every day. If regulatory action isn’t going to help much, then it may make sense to return to the previous standard.

Sen. Carper opined that we need to rely more on public transportation and do more remote working to reduce air pollution based on what we learned from the lockdowns. Driving did fall about 60%, but use of public transportation also fell about 75%. People were back in their cars, making essential trips, by May, and vehicle traffic is back to near normal, but public transport ridership has not recovered.

Let’s learn real lessons from the pandemic, instead of twisting facts to support favored policy solutions.

David T. Stevenson is director of the Center for Energy & Environmental Policy, Caesar Rodney Institute.