Newbury, Heron, Kirkbride, 2024

“Depression and anxiety were measured at age 13 years via parent-completed Development and Well-being Assessments. Responses were classified into probabilistic bands according to Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria for major depressive disorder and generalized anxiety disorder, and dichotomized for analysis (bands 0-2, 0; bands 3-5, 1).”

Once the participants were 13 years old, the researchers had the participants’ parents complete a well-being assessment to measure depression and anxiety in the participants. After responses were collected, they were turned into scores (bands 0-5) depending on the criteria they met, from a diagnostic manual. Then, they were divided into two final groups (bands 0-2 being group 0, and bands 3-5 being group 1), to simplify the presence or absence of depression and anxiety.

“Air pollution comprises toxic gases and particulate matter (ie, organic and inorganic solid and liquid aerosols) of mostly anthropogenic origin. Understanding the potential effect of air pollution on mental health is increasingly crucial, given the human and societal cost of poor mental health, the global shift toward urban living, and the backdrop of emissions-induced climate change.”

Air pollution is made up of many toxic gases and particles that are mostly human made which can impact the environment. It is important to understand the possible effects of air pollution on mental health, since there is an increase in urban neighbourhoods, because there is an increase in climate change from air pollution, and poor mental health can negatively affect human lives.

“Following covariate adjustment, IQR increases in PM2.5 during pregnancy were associated with elevated odds for depression (eg, AOR, 1.10 [95%CI, 1.02-1.18]; P = .01 during pregnancy). There were no associations between NO2 (eg, AOR, 1.10 [95%CI, 0.98-1.24]; P = .10 during pregnancy) or noise pollution (eg, AOR, 1.02 [95%CI, 0.89-1.18]; P = .74 during pregnancy) and depression.”

After adjusting for different factors that might influence the effect of air pollution on mental health, the researchers found that PM2.5 exposure during pregnancy is linked to an increased risk of depression. They found that exposure to NO2 and noise pollution during pregnancy were not linked to an increased risk of depression.

“For noise pollution, evidence was strongest for childhood and adolescent exposure. Childhood and adolescent noise pollution exposure could increase anxiety by increasing stress and disrupting sleep, with high noise potentially leading to chronic physiological arousal and disruption to endocrinology. Noise pollution could also impact cognition, which could increase anxiety by impacting concentration during school years.”

The effect of noise pollution on mental health is most noticeable in children and adolescents that have been exposed to noise pollution. Noise pollution exposure in children and adolescents could increase stress and disrupt sleep, which might increase anxiety. High noise pollution can also disrupt hormonal and physiological systems in growing children and adolescents. Anxiety may also increase as noise pollution can impact concentration and cognition in school.

In future research, it would be beneficial to test a wider range of air pollutants to see if and how an association between pollution and mental health is made. This study mainly focused on two types of air pollutants, but I think having multiple types may show a greater presence or absence of depression or anxiety in participants. The study also used participants in high-income urban neighbourhoods, who may have greater access to healthcare and mental facilities. Using participants from low-income neighbourhoods may show results that cater to a larger and more at-risk population.

The most challenging part to understand was reading the results section. There were terms I was not familiar with that I had to research definitions for, to understand why the results did or did not show an increase of mental disorders. For example, in some parts the authors said that an environmental toxin had a large effect on increased mental health issues, but later on, after doing multiple statistical analyses I did not understand, the results changed and showed no effect.