A new study shows that air quality in the United States suffered between 2016 and 2018, after seven straight years of improvement starting during the first years of Barack Obama's administration.

The rise in pollution— which data shows started in 2016, just before Donald Trump took office and after years of economic recovery in the United States — has led to thousands of premature deaths across the country, according to the economists from Carnegie Mellon University who studied Environmental Protection Agency data from those time periods.

“That increase was associated with 9,700 premature deaths in 2018,” wrote Karen Clay and Nicholas Muller in a new paper detailing their research.

The researchers determined that the deaths had a heavy economic toll, in addition to the obvious human loss: around $89 billion in damages, they say.

The causes of the rise in particulate matter comes from a variety of sources, the researchers said, including a strong US economy, the burning of wildfires in parched areas of the country, and the destruction of American environmental protection rules, which Donald Trump’s administration has pursued vigorously.

London smog: in pictures Show all 13 1 /13 London smog: in pictures London smog: in pictures November 1922: Fog at Ludgate Circus, London. (Photo by Topical Press Agency/Getty Images) Topical Press Agency Getty Images London smog: in pictures Fog At Liverpool Street Edward Miller Getty Images London smog: in pictures A London policeman wearing a mask for protection against the thick fog which hit most of the country and turned to smog in the city. (Photo by Keystone/Getty Images) Keystone Getty Images London smog: in pictures A man guiding a London bus through thick fog with a flaming torch. (Photo by Monty Fresco/Getty Images) Monty Fresco Getty Images London smog: in pictures BOAC airliners sit grounded on the runway at London Airport due to heavy fog gripping the capital PA PA Archive/PA Images London smog: in pictures A London bus makes its way along Fleet Street in heavy smog, 6th December 1952. (Photo by Edward Miller/Keystone/Hulton Archive/Getty Images) Edward Miller Getty Images London smog: in pictures Heavy smog in Piccadilly Circus, London, 6th December 1952. (Photo by Central Press/Hulton Archive/Getty Images) Central Press Getty Images London smog: in pictures 06/12/1952 - On this Day in History - A thick smog envelopes London causing many deaths and injuries London was blanketed by thick fog (smog) at Ludgate Circus. This picture was taken at 2pm. On the right is a Bus emerging from Fleet Street, while on left is seen glow of the street fog lighting in operation PA PA Archive/PA Images London smog: in pictures 2nd October 1960: An autumn mist falls on Victoria Bus Station in London. (Photo by Fox Photos/Getty Images) Fox Photos Getty Images London smog: in pictures 5th December 1962: A heavy fog descends on Christmas shoppers in London's Regent Street. (Photo by Peter King/Fox Photos/Getty Images) Peter King Getty Images London smog: in pictures 5th December 1952: Morning traffic at Blackfriars, London almost at a standstill because of the blanket smog. (Photo by Don Price/Fox Photos/Getty Images) Don Price Getty Images London smog: in pictures PA Photo: OLDHAM, CIRCA 1956. A library file picture of housing and factories in Oldham, Lancashire, taken from the Pennines. A heavy smog hangs over the area. PA PA Archive/PA Images London smog: in pictures 06/12/1952 - On this Day in History - A thick smog envelopes London causing many deaths and injuries London was blanketed by thick fog (smog) at Ludgate Circus. This picture was taken at 2pm. On the right is a Bus emerging from Fleet Street, while on left is seen glow of the street fog lighting in operation PA PA Archive/PA Images

When it comes to the economy, a major culprit of pollution has been the increased use of trucks to transport goods, the researchers said, leading to increased burning of dirty fossil fuels.

“The chemical composition of particulates point to increased use of natural gas and to vehicle miles travelled as likely contributors to the increase” in pollution, they wrote. “We conclude that the effect is due to diesel vehicles as well as some industrial boilers.”

The rise in wildfires was marked beginning in 2016, especially in California, where devastating blazes have occurred very close to population centres.