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Higher ozone levels predicted increase in depressive symptoms over time, study finds

Exposure to ozone from air pollution has been linked to an increase in depressive symptoms for adolescents over time, even in neighborhoods that meet air quality standards, according to new research published by the American Psychological Association.

Ozone is a gas that is produced when various pollutants from motor vehicle exhaust, power plants and other sources react to sunlight. Higher ozone levels have been linked to various physical ailments, including asthma, respiratory viruses and premature death from respiratory causes. This study is the first to link ozone levels to the development of depression symptoms in adolescents over time. Those symptoms may include persistent feelings of sadness or hopelessness, difficulty with concentration, sleep disturbances and thoughts about suicide.

“I think our findings really speak to the importance of considering air pollution’s impact on mental health in addition to physical health,” said lead researcher Erika Manczak, PhD, an assistant professor of psychology at the University of Denver.

The researchers analyzed data from a previous study about early life stress with 213 adolescent participants (aged 9 to 13 years old) in the San Francisco Bay area. The researchers compared data about the adolescents’ mental health over a four-year period with Census tracts for their home addresses and air quality data for those tracts from the California Environmental Protection Agency.

Adolescents who lived in areas with relatively higher ozone levels showed significant increases in depressive symptoms over time, even though the ozone levels in their neighborhoods didn’t exceed state or national air quality standards. The findings weren’t affected by the participants’ sex, age, race, household income, parental education or socioeconomic characteristics of their neighborhoods. The research was published online in Developmental Psychology.

“It was surprising that the average level of ozone was fairly low even in the communities with relatively higher ozone exposure,” Manczak said. “This really underscores the fact that even low levels of ozone exposure have potentially harmful effects.”

Ozone and other components of air pollution can contribute to high levels of inflammation in the body, which has been linked to the onset and development of depression. Adolescents may be especially sensitive to these effects because they spend more time outdoors.

The study included a relatively small sample size from one area of the United States. The findings are correlational so it can’t be proven that ozone levels caused an increase in depressive symptoms, only that there is a link between them. It’s also possible that other components of air pollution besides ozone could be a factor.

Because air pollution disproportionately affects marginalized communities, ozone levels could be contributing to health disparities, Manczak said. Communities also should consider ways to reduce ozone exposure, such as holding youth sporting events indoors when necessary and limiting driving during peak hours of air pollution alerts. Investment in clean and renewable energy sources that reduce air pollution also could be helpful.

“I believe state and federal air quality standards should be stricter, and we should have tighter regulations on industries that contribute to pollution,” Manczak said. “Our findings and other studies suggest that even low levels of ozone exposure can pose potentially serious risks to both physical and mental health.”

Air pollution linked to depressive symptoms in adolescents: Higher ozone levels predicted increase in depressive symptoms over time, study finds — ScienceDaily

Since 2013, China has implemented a series of emission reduction policies, such as the “Clean Air Action” and the “Blue Sky Protection Campaign.” Accordingly, the concentrations of air pollutants have generally decreased significantly. However, PM2.5 pollution still occurs in China under unfavorable weather conditions. El Niño–Southern Oscillation (ENSO) is the strongest signal that modulates the interannual variations in the ocean–atmosphere system near the equator. It oscillates between its warm period (El Niño) and cold period (La Niña) and can significantly influence aerosol concentrations.

Recently, a team lead by Prof. Yang Yang from Nanjing University of Information Science and Technology studied the variability of wintertime PM2.5 concentrations in four megacity clusters in China during ENSO events from 2014 to 2021.

Their paper reveals that the wintertime PM2.5 concentrations in the Beijing–Tianjin–Hebei and Fenwei Plain regions during El Niño years are higher than those during La Niña years, which can be explained by the anomalous winds during ENSO events. In the Pearl River Delta region, PM2.5 concentrations decrease in El Niño relative to La Niña years owing to the enhanced precipitation in El Niño events. In the Yangtze River Delta region, the comprehensive effects of wind and precipitation anomalies lead to the unpredictability of the impacts of ENSO on PM2.5.

“ENSO’s modulation of PM2.5 can be stronger than the year-by-year emission changes,” says Prof. Yang. The results have been published in Atmospheric and Oceanic Science Letters.

Impacts of El Niño–Southern Oscillation diversity on wintertime PM2.5 pollution in four Chinese megacities

Illnesses including rheumatoid arthritis and Crohn’s more likely after long-term exposure to particulates, study finds

Long-term exposure to air pollution can increase the risk of autoimmune disease, research has found.

Exposure to particulates has already been linked to strokes, brain cancer, miscarriage and mental health problems. A global review, published in 2019, concluded that almost every cell in the body could be affected by dirty air.

Now researchers at the University of Verona have found that long-term exposure to high levels of air pollution was associated with an approximately 40% higher risk of rheumatoid arthritis, a 20% higher risk of inflammatory bowel disease such as Crohn’s and ulcerative colitis, and a 15% higher risk of connective tissue diseases, such as lupus.

The study, published in the journal RMD Open, took comprehensive medical information about 81,363 men and women on an Italian database monitoring risk of fractures between June 2016 and November 2020. About 12% were diagnosed with an autoimmune disease during this period.

Each patient was linked to the nearest air quality monitoring station via their residential postcode.

The study analysed average long-term exposure to fine particulate matter (known as PM10 and PM2.5), which is produced by sources such as vehicles and power stations. Concentration levels of 30µg/m3 for PM10 and 20µg/m3 for PM2.5 are the thresholds generally considered harmful to human health.

The study concluded that overall, long-term exposure to particulates above these levels was associated with, respectively, a 12% and 13% higher risk of developing an autoimmune disease.

Felicity Gavins, the director of the Centre for Inflammation Research and Translational Medicine at Brunel University London, said: “This study further supports the mounting evidence suggesting a link between air pollution exposure and immune-mediated diseases.”

But she cautioned against inferring that dirty air caused these conditions. “Whether air pollution exposure specifically causes autoimmune diseases remains controversial, although there is no doubt that there is a link.”

She also said more research was needed to ascertain why some areas of Italy had seen heightened growth in autoimmune conditions, and to look at the impact of passive smoking on the findings.

The researchers acknowledge their findings do not prove a causal link and that other factors may be at play, including lack of information on when autoimmune disease symptoms began, or that air quality monitoring might not reflect personal exposure to pollutants, and that the findings might not be more widely applicable because study participants largely comprised older women at risk of fractures.

But air pollution has already been linked to immune system abnormalities, and smoking, which shares some toxins with fossil fuel emissions, was a predisposing factor for rheumatoid arthritis, said Dr Giovanni Adami, one of the report’s authors and a rheumatologist at the University of Verona.

“The World Health Organization has recently identified air pollution as one of the greatest environmental risks to health,” he said. “Our study provides new real-life evidence on the link between autoimmune diseases and air pollution exposure. In addition, there is a strong biological rationale underpinning our findings. However, a causal relationship is hard to prove. Indeed, it is unlikely that randomised controlled studies could be conducted on such topic.”

Air pollution linked to higher risk of autoimmune diseases | Air pollution | The Guardian