Will our clean air last after COVID-19? Study says it's possible

Since millions of Californians began staying home and avoiding the roads in March, air quality in the Golden State has visibly improved. However, once life returns to normal, air pollution levels will likely return to pre-pandemic levels.

A team of researchers at UCLA says this is not necessarily our destiny.

In a peer-reviewed study published May 4 in the journal Nature Sustainability, they describe a path for California to significantly reduce greenhouse gas emissions and air pollution by 2050. Taken together, these measures would prevent an estimated 14,000 premature deaths from air pollution-related illnesses each year, while helping to reduce climate change, the researchers say.

Air pollution is linked to a range of health problems, including respiratory and cardiovascular diseases, neurological problems, cancers and adverse pregnancy outcomes. People exposed to high levels of air pollution also have a higher risk of contracting influenza and are more vulnerable to VIDOC-19.

"A global pandemic is not necessary to create cleaner air and healthier lives," said Yifang Zhu, one of the study's lead authors and a professor at UCLA's Fielding School of Public Health. "Climate action directly benefits people at the local and regional level by creating cleaner air. The public health benefits are both immediate and long-term, and we can save the economy billions each year.

To limit the global temperature increase to 3.6 degrees Fahrenheit (2 degrees Celsius) above pre-industrial levels by 2100 - the threshold to avoid the most serious effects of global warming - the UN Intergovernmental Panel on Climate Change warns that man-made emissions will have to be reduced to almost zero, and any remaining emissions will have to be captured and stored. This is called net zero emissions, or carbon neutrality.

It is not easy to achieve this globally, but the study shows how it can be done in California, creating the first-ever roadmap for the state to achieve it by 2050 using existing policies and technologies.

"Nothing we suggest is science fiction, but it will take a lot more than what we are doing now," said study co-author Tony Wang, a California Air Resources Board engineer who recently earned a PhD in environmental science and engineering from UCLA.

Collaborators from UCLA's Joint Institute for Regional Earth System Science and Engineering contributed state-of-the-art modeling to analyze how ambient air quality would change under a zero net emissions scenario. Researchers then combined the model with epidemiological data and information to estimate the impact of cleaner air on public health.

In addition to finding that about 14,000 premature deaths could be prevented each year in California by 2050, zero net emissions could also be achieved:

Reduce acute respiratory symptoms in 8.4 million adults.
Reduce asthma exacerbation in 1 million children.
Reduce the number of lost work days by 1.4 million.
Reduce the number of hospital admissions for cardiovascular disease by 4,500.
While all communities would benefit, the 25 percent of the state's most polluted census tracts would receive about 35 percent of the health benefits resulting from the expected improvements in air quality, according to the study.

"We are pleased to see that when you reduce these emissions, you bring disproportionately higher levels of air quality benefits to disadvantaged communities," said Mr. Zhu.

In contrast to the current VIDOC-19 crisis, achieving zero net emissions after the pandemic would benefit the economy. By 2050, the monetary savings from reducing greenhouse gases will exceed the cost of $109 billion per year, according to the study.

The authors of the study intend that their research will help national and local policymakers visualize how bold climate change measures will directly benefit people.

"Reducing greenhouse gas emissions in our state will not only slow global climate change, but more importantly improve air quality and protect the health of people in our local community," said study co-author Bin Zhao, a former UCLA scientist who is now an earth science researcher at the Pacific Northwest National Laboratory.