SALT LAKE CITY — A new analysis of March pollution levels along the Wasatch Front shows the pandemic-fueled shutdown of schools and businesses dramatically reduced pollutants that form ugly haze and threaten public health.
While March air quality is typically good most years, March 2020 will likely be viewed as a historic benchmark that demonstrates what can happen when vehicles leave the roadways and people shelter in place.
“For environmental scientists, this was a once-in-a-lifetime opportunity to study the air quality impacts of fewer cars on the road,” said Bryce Bird, director of the Air Quality Division within the Utah Department of Environmental Quality.
Bird said there will be additional analysis carried out for the period when people were teleworking and driving less, and is hopeful the results will help inform behavior and policy in the future.
The research focused on the last half of March, when physical distancing measures went into effect, and used data from multiple air monitoring stations in the Salt Lake Valley.
- Fine particulate matter, or PM2.5, was down 59%, and especially at night.
- Oxides of nitrogen were lower due to traffic reductions, especially during rush hour peaks. The pollutant was 57% lower than the average March and nitrogen dioxide was 36% lower than an average March.
- Carbon dioxide levels were 19% and 33% lower than average at the Sugarhouse and University of Utah stations, respectively.
The results, researchers say, are some of the first to integrate ground-based air quality and greenhouse gas emissions with satellite observations to understand how emissions have changed during physical distancing measures.
“These measurements, taken together, paint a consistent picture of cleaner air from reduced emissions, especially from reduced traffic,” said Logan Mitchell, research assistant professor in the Department of Atmospheric Sciences at the University of Utah who conducted the analysis.
“It shows how fast the air quality improves after a reduction in emissions and suggests that as the economy starts to recover and emissions ramp up, we’re going to see our air quality get worse again,” he noted.
Mitchell said there is more analysis that needs to be done, including a review of weather conditions that will give a more complete picture of the emissions from March 2020 compared to previous years.
These preliminary findings, he added, provide a teaching opportunity when it comes to understanding air quality along the Wasatch Front.
“I think the lesson is that it shows if we reduce emissions it is possible to have better air quality. It also shows that air quality is a result of our activities. It is here locally. As soon as we lower our emissions, the air quality immediately gets better in a matter of days,” Mitchell said. “That to me is a really powerful symbol of what we could have in the future if we reduce emissions.”
Mitchell said the numbers from the Utah Department of Transportation indicate traffic declined 40% to 50%.
“Obviously we don’t want a global pandemic to reduce emissions, but if we were to convert 50% of our cars to electric, that would produce the same results,” Mitchell said.
Like many people, Mitchell is taking a crash course in working from home and making adjustments to how he works.
But he is hopeful once the economy gets going again that this data provides an opportunity for reshaping behavior.
“When the pandemic is over, there is going to be an investment to rebuild the economy,” he said. “It is going to be an open question about what we should invest in. I think it would be a smart investment to invest in renewable energy and electric vehicles.”