Despite China’s rapid air pollution reduction, research reveals it’s still killing people by suicide and other methods

Researchers have discovered a novel method to investigate a potential link between air pollution and suicide. Their findings not only validated the existence of the association but also indicated that it is more evident than anticipated. In addition to the existing arguments to cease using fossil fuels, here is another one.

There is a strong connection between air pollution and physical health issues. A recent study has also shown that it may negatively impact mental health, perhaps leading to an increase in suicide rates. Dr. Tamma Carleton from the University of California, Santa Barbara, pointed out that this situation exemplifies association without implying causality. “Air pollution is correlated with various factors, which has been a significant challenge in previous research on this issue,” said Carleton. Weekdays have higher pollution levels compared to weekends, but it would be unsafe to imply that pollution is causing individuals to commit suicide.

“Our objective was to specifically examine the impact of pollution on suicide, excluding other potentially related factors,” said Carleton. Carleton and his colleagues looked into times when pollution levels rose because of temperature inversions. This is when levels of particles 2.5 microns or smaller (PM2.5) rose regardless of other conditions. These phenomena happen when a warm air layer prevents the dispersion of pollutants by trapping cold air below, leading to the accumulation of pollutants in a specific area. Some cities are more susceptible to these inversions due to the presence of adjacent hills.

If the pollution-suicide link is chronic due to prolonged exposure, this test would not be beneficial. If there is a strong relationship, inversions may help eliminate all the complicating aspects.

Carleton and co-authors found a 25% rise in suicide rates in Chinese counties from 2000 to 2019 during weeks with pollution spikes caused by inversions. They find that suicide rates significantly rise with increased air pollution. Older women see a 2.5-times higher rise in rates compared to the general population. The authors provide many potential reasons why older women are more susceptible, but they do not have a method to differentiate between them at this time.

Suicide rates do not decrease in the weeks after an inversion, which contradicts the assumption that additional pollution is only accelerating an inevitable tragedy.

Carleton’s interest in the subject was piqued after demonstrating that high temperatures lead to a rise in suicides in India, a troubling discovery in a world experiencing climate change. Nevertheless, she saw a worldwide decline in suicide rates, even as temperatures rose, with China seeing a particularly rapid decrease. The reduction in air pollution in Chinese urban areas is mostly due to the replacement of outdated coal-burning equipment with cleaner technology.

“Thirty years of warming in India had a similar impact on suicide rates as approximately five years of air pollution control in China,” said Carleton, with the latter measure saving nearly 46,000 lives. She pointed out that 90 percent of suicides are not attributable to pollution. The epidemic likely caused further confusion.

Although it is challenging to put a number on overall mental health issues, it is possible that suicide is only a small portion of a much larger issue that is also a result of air pollution.

This discovery is excellent for China. Air pollution has decreased significantly, but it is expected to decrease considerably more due to the significant rise in solar and wind energy production, which will likely begin displacing even very clean coal production, perhaps beginning this year. Electric cars have become quite popular in China, causing the number of petrol and diesel vehicles to reach their peak shortly.

It is not a good discovery for regions where pollution levels are rising, but it suggests that countries could gain additional benefits by forgoing the use of coal and oil during development and switching instead to renewable energy sources.

“Suicide and mental health are commonly viewed as issues that need to be addressed and resolved on an individual basis,” Carleton said. “This outcome highlights the significant impact of public policy, particularly environmental policy, in addressing mental health and suicide crises beyond individual-level actions.”

The research is featured in Nature Sustainability.