Air quality in Los Angeles has improved during the COVID-19 pandemic, UCLA professors and the Environmental Protection Agency confirmed in April.
Stay-at-home orders have reduced road traffic, which is a major source of air pollution, said Yifang Zhu, associate director of the Center for Clean Air at the UCLA Institute of the Environment and Sustainability. Burning gasoline releases volatile organic compounds, also known as VOCs, and nitrogen oxides into the air.
“This creates secondary ozone, and that is the key source for Los Angeles smog,” Zhu said.
Traffic on Los Angeles roads, especially on freeways, has decreased since mid-March, Zhu said. The reduction in emissions from transportation has reduced pollution for the past six weeks, creating the longest period of “good” air quality in over two decades, according to CNN.
A decrease in Southern California traffic led to decreases in microscopic air pollutants known as fine particulate matter, or PM 2.5. This contributed to a 20% improvement in air quality across Southern California, according to Zhu’s findings and Environmental Protection Agency data.
Recent weather conditions, including increased rainfall during April, also improved the air quality, Zhu added. This rain has further reduced harmful chemicals in the air, making the air the cleanest it has been in decades, she said.
The “good” air quality streak has come to an end, however, as the temperature has increased in Southern California. While decreased emissions likely made a significant contribution to decreased pollution, air quality will likely continue to worsen as temperatures rise and precipitation falls in the upcoming months, according to an article published in the Los Angeles Times.
Poor air quality has negative consequences for public health; increased concentrations of carbon monoxide and fine particulate matter in the air can lead to increases in asthma attacks and hospital admissions for respiratory diseases, said Suzanne Paulson, director of the Center for Clean Air.
Efforts to improve air quality in Los Angeles over the past few decades have decreased the amount of overall carbon in the air and improved lung capacity in children, she added.
Poor air quality can also increase the risk of dying of COVID-19, since it is a respiratory disease, Zhu said.
Jesus Araujo, director of environmental cardiology at the UCLA David Geffen School of Medicine, said preliminary data shows that areas with more pollution have a higher COVID-19 fatality rate than areas with less pollution. In addition, air particles have been found to carry portions of the COVID-19 virus, however it isn’t known if those portions can contribute to the virus’ transmission, he added.
Araujo said he recommends those with preexisting conditions try to spend time in areas with less air pollution, even after the pandemic.
Human activity is the primary cause of poor air quality, Paulson said. Although vehicles are one of the largest contributors, industrial sources, planes, ships and any type of burning that happens inside of homes can also negatively impact air quality, Paulson added.
The improved air quality resulting from stay at home orders will be quickly reversed when the pandemic ends, Zhu said. More long-term actions, such as driving less, will be necessary to improve air quality permanently.
“It doesn’t take very long for the air pollution to come back once you get gas emissions on the road again,” she said.
Zhu said she thinks society should evaluate how people can work together to improve air quality in the long term.
“We want to communicate to the public that we don’t need a pandemic to get better air,” Zhu said.