Air and road travel has decreased during the Covid period, and air pollution levels have also fallen

In the first year of the Covid-19 pandemic, global road travel and commercial flight activity fell by 50% and 60%, respectively, compared to pre-pandemic levels. During the lockdowns imposed by cities in the early months of Covid, flight activity in particular came to a standstill, dropping by 96 percent — nearly triple the percentage of flight reductions after the 9/11 attacks.

This unexpected and widespread outage has given researchers the opportunity to study the effects of these changes in mobility on air pollution, particularly ultrafine particles. Now, a new study by the Boston University School of Public Health (BUSPH) has found that the reduction in aviation and road traffic in the first months of the outbreak reduced ultrafine particle concentrations by 50%.

It was published in the magazine Environmental Science and Technology LettersThe study analyzed measurements of ultrafine particles, called particle number concentrations (PNC), collected on rooftops near Boston’s Logan International Airport before and during the first year of Covid. The findings show that during the April-June 2020 emergency period, average PNC was 48% lower than before the outbreak, with 74% less flight activity, 51% less highway traffic, and 39% less local traffic than pre-pandemic levels.

Overall air quality measurements took place from April 2020 to June 2021, and the researchers compared them to pre-pandemic measurements from 2017 and 2018.

By June 2021, traffic volumes had returned to pre-Covid levels, while flight activity remained 44% lower than normal. Similar to traffic volume, average PNC levels have returned to normal in the summer of 2021—except for Logan Airport, where the area is lower.

The findings build on previous studies on PNC, which focused mainly on road traffic emissions, over a very short period of time. The new study is the first to separate the contributions to PNC between aviation and automobile-related emissions, providing a clearer understanding of the specific emissions produced by each transportation source.

Identifying and quantifying the sources of emissions that contribute the most to air pollution levels in an area or region is critical to air quality management, the researchers said.

“Urban air pollution is a major public health threat, and living in neighborhoods near sources of fine particles such as major highways, trains, and airports has been shown to have significant health effects,” said study leader Sean Mueller, Ph.D. .D. student in the Department of Environmental Health at BUSPH.

“Our work shows that while aircraft can contribute to some high community-level exposures to ultrafine particles, these exposures mainly occur under specific weather conditions. Following the differences in road and flight activity before and during the outbreak allowed us to understand this. In the community, PNC typically measures road traffic patterns.” It follows—that is, it’s highest during normal transit rush hour and lowest after midnight—but the highest air pollution levels occur when the station lands at Logan Airport.

Ultrafine particles, which are 800 times smaller than a human hair, are toxic substances that can cause inflammation, especially in the lungs, brain and other organs. They are also not regulated by the US Environmental Protection Agency. About 40 million people in the United States, including many in low-income neighborhoods, live near major airports and bear the health effects of exposure to these pollutants.

In the absence of federal regulation, there are still policy changes that could help reduce exposure, including the adoption of sustainable aviation fuel technology such as low-sulfur fuel and electric motors, said assistant professor Dr. Kevin Lane, senior author of the study. Environmental Health at BUSPH.

“The EPA currently believes there is insufficient health evidence to declare an optimal air quality standard, so more research is needed to support regulatory development,” says Lane.

“Pending federal action and the development and integration of new technologies to reduce exposure to air pollution, action can be taken at the local level by bringing together communities near airports, researchers, and airport managers to explore ways to reduce community exposure. Including.