Pollution from freeways and wildfires turns the morning sky bright orange over Los Angeles.

The smog that frequently hangs over cities like Los Angeles, Paris, Mumbai and Beijing may seem like a reality of modern life, but it’s also responsible for significantly more deaths, as well.

It causes as many as one in five premature deaths, in fact, according to a new study published in the journal Environmental Research.

“Our study certainly isn’t in isolation in finding a large impact on health due to exposure to air pollution, but we were blown away by just how large the estimate was that we obtained,” Eloise Marais, an expert in atmospheric chemistry at University College London, and a co-author of the study, said in a statement.

A separate report by the International Energy Agency offered a bit more positive news. It forecast global carbon dioxide emissions dropping about 8% on a daily basis due to cutbacks on everything from manufacturing to driving during the coronavirus pandemic. That is expected to be a temporary reprieve, however.

Air pollution more deadly than anticipated

China is taking dramatic steps to improve the air quality in its largest cities.

Air pollution has long been recognized as a serious health hazard but the new study by Harvard University and three British universities was aimed at developing hard data. The findings are particularly worrisome because they indicate the number of premature deaths specifically linked to the use of fossil fuels is twice what previous research had indicated.

Smog isn’t a new problem. As former President Ronald Reagan once declared, trees contribute to unwanted emissions. And the massive forest fires that swept through California last year created major health problems, not only for those in-state, but also for those living in areas where smoke was blown beyond California’s borders.

All told, the researchers concluded that 8.7 million people worldwide die from exposure to the particulates released by burning oil, coal and other fossil fuels each year – about a fifth of total deaths resulting from air pollution. Much of that comes from transportation sources, including automobiles and aircraft. And even the nascent switch to electrified vehicles could pose a risk if they rely on energy coming from non-renewable sources.

New study focuses specifically on fossil fuel impact

Paris banned on diesel vehicles in the city to help alleviate the air quality issues it faced.

Previous efforts to quantify the problem largely relied on satellite and surface imagery which meant scientists were “seeing only pieces of the puzzle,” said co-author Loretta J. Mickley, resulting in “gaps in the data.”

The new study aimed to distinguish between the sources of air pollution, separating out the impact of burned fuels, wildfire particulates and even dust swept up from deserts.

The impact varies by region, the final report indicated, reflecting factors such as the dependence upon fossil fuels and the lack of pollution control technologies. In Eastern Asia, for example, 30.7% of premature deaths were attributed to air pollution.

That should come as no surprise considering the problems in coal-dependent China. The government several years ago revised its pollution measurements as the numbers routinely went off the normal scale in cities like Beijing and Shanghai.

In Europe, the study found, 16.8% of premature deaths were blamed on fossil fuel pollution. The report did not break out specific types of pollution which could have indicated whether the European numbers reflect the continent’s traditionally heavy reliance on diesel fuel for automobiles and trucks. Paris, for one, has set in place a mandate that will soon ban the sale and use of vehicles running on diesel.

Traffic on I-405 in Los Angeles is uncharacteristically light in the wake of the coronavirus.

As for the United States, the study blamed 13.1% of annual premature deaths on fossil fuels.

Pandemic could have unexpectedly positive impact

The coronavirus pandemic could provide at least one positive outcome, according to the separate report by the IEA released last year. It estimated that fossil fuel emissions would drop by 8%, the largest dip ever recorded, during the pandemic.

Preliminary reports since then have indicated substantial improvements in air quality in places like Los Angeles. But follow-up studies are needed, environmental and energy researchers said, to see if the reductions in air pollution continue as life slowly returns to more “normal” conditions.