When the open-hearth Utah Valley Steel Mill in the United States closed for 13 months, air pollution fell, creating a “natural experiment” that scientists drew on for years, producing studies that yielded startling results.
Hospitalisations in the area for pneumonia, pleurisy, bronchitis and asthma plummeted by half, there were 40 per cent fewer missed school days, and daily mortality fell by 16 per cent for every 100 µg/m3 drop in PM10 (pollution particles a fraction the size of a human hair) concentrations.
Women in the valley who were pregnant during the mill closing were less likely to deliver their babies prematurely.
These were among dozens of peer reviewed studies from around the world that a group of medical researchers reviewed, finding that reductions in air pollution produced fast and dramatic improvements to health, and cut the number of deaths by all causes.
The new research, “Health Benefits of Air Pollution Reduction,” published in the American Thoracic Society’s journal, Annals of the American Thoracic Society, found that anywhere that air pollution was reduced and at any scale— from the national level, through to cities, even to the home— yielded health benefits that were “almost immediate and substantial”, and stretched into the long term.
“Sweeping policies affecting a whole country can reduce mortality within weeks. Local programmes, such as reducing traffic, have also promptly improved many health measures,” said lead author of the report, Dean Schraufnagel, MD, ATSF, in a press release.
But the magnitude and speed of the health payoff of reducing air pollution surprised even the doctors who conducted the study.
“With some of this stuff, I had to do a double take,” Dr Schraufnagel told the New Scientist.
“We knew there were benefits from pollution control, but the magnitude and relatively short time duration to accomplish them were impressive,” he said.
The researchers found that this experience had been repeated in the United States and around the world.
For the 2008 Beijing Olympics, when China clamped down on factory emissions and instituted an odd-even ban on vehicles, lung function improved within two months, with fewer asthma-related visits to the doctor and less cardiovascular mortality.
The same happened in Atlanta, at the 1996 Olympic Games, when a 17-day “transportation strategy” closed parts of the city to help athletes make it to their events on time, while also greatly decreasing air pollution: in the following four weeks, children’s visits for asthma to clinics dropped by more than 40 per cent, trips to emergency departments fell by 11 per cent, and hospitalisations for asthma by 19 per cent.
Reducing air pollution in the home also delivered health benefits: in Nigeria, families with clean cookstoves that reduced indoor air pollution during a nine-month pregnancy term saw higher birthweights of newborns, longer pregnancies, less perinatal mortality (stilbirths and deaths of babies under seven days old).
The report found that since the Clean Air Act was enacted in the U.S. 25 years ago, the U.S. EPA estimated that the health benefits it brought people exceeded the costs by 32:1, saving 2 trillion dollars, and has been lauded as one of the most effective public health policies of all time in the country. Emissions of major pollutants dropped by 73 per cent, while U.S. economic output grew by over 250 per cent.
Schraufnagel told the Guardian that the findings made sense. Low oxygen levels are a key factor in coronary heart disease, for example, so the risk can be made worse by a bad air day.
“That could tip you over and cause a heart attack immediately,” he said.
The researchers found that health benefits accrued even when air pollution already below WHO levels were reduced further.
Thousands of studies have linked air quality to a whole spectrum of health impacts, affecting every organ in the body, and throughout the life cycle, from womb to grave, but this study looked retrospectively at what actually happened once air pollution fell when policies took effect.
The WHO has long called air pollution a public health emergency, attributing 7 million deaths (including 600,000 child deaths) to exposure to unhealthy air, which 90 per cent of the world’s population breathes.
The UN has called for urgent action to tackle the problem, which has direct links to action on climate change, as the sources of emissions that drive global warming and cause bad air quality overlap significantly; for example, two-thirds of outdoor air pollution is from fossil fuel consumption.
“Our findings indicate almost immediate and substantial effects on health outcomes followed reduced exposure to air pollution. It’s critical that governments adopt and enforce WHO guidelines for air pollution immediately,” said Schraufnagel.
“What are we waiting for? Here’s the evidence,” he continued. “If it is competing interests or commercialism [blocking action] then we have to tell the people, and the people then can come out strongly and tell politicians we want cleaner air.”
Read the report: Health Benefits of Air Pollution Reduction
Read the press release: New Report Shows Dramatic Health Benefits Following Air Pollution Reduction