However, this positive impact is more likely to be observed in wealthier populations, the research notes.

Since the advent of e-vehicles, often hailed as the future of mobility, there has been increasing evidence of reduced air pollution associated with the use of these modes of transport.

But few studies have focused on the effects on respiratory health, according to researchers from the University of Southern California’s Keck School of Medicine, who conducted the study published in “Science of the Total Environment”.

They focused on publicly available datasets to analyse various factors in several cities in California between 2013 and 2019.

The researchers began by looking at changes in the use of zero- or low-emission vehicles (electric cars, hybrid cars, hydrogen fuel cell cars), before looking at air pollution levels and finally at asthma-related emergency room visits.

The study found that, as the adoption of zero-emission vehicles increased within a city or neighbourhood, local air pollution levels and emergency room visits decreased. By area code, for every additional 20 electric cars per 1,000 people, the researchers noted a 3.2% decrease in the rate of asthma-related emergency-room visits, and a small suggestive reduction in nitrogen dioxide levels.

However, the study notes that a “zero-emissions vehicle adoption gap” threatens the equitable distribution of any associated benefits. Indeed, the researchers found that while the total number of e-vehicles has increased over time, the shift appears to be slower in low-income neighbourhoods.

“That disparity points to an opportunity to restore environmental justice in communities that are disproportionately affected by pollution and related health problems,” the authors added.