Seasonal Depression in Summer - Effects of Poor Air Quality

Though commonly associated with shorter winter days, many individuals experience seasonal depression as the weather warms. This mental health challenge is a specific category of seasonal affective disorder (SAD), and there is compelling evidence suggesting that poor air quality might be a contributing factor.

Seasonal affective disorder

Seasonal affective disorder, commonly known as SAD, is defined by the Mayo Clinic as "a type of depression that's related to changes in seasons." The official designation by the American Psychiatric Association is "Major Depressive Disorder with a Seasonal Pattern" or MDD-SP. Symptoms of SAD resemble classical depression, with distinctions between fall/winter and spring/summer varieties, as outlined below:

Fall & Winter SAD	Spring & Summer SAD
Oversleeping	Insomnia
Weight Gain/Increase in Appetite	Weight Loss/Decrease in Appetite
Low Energy/Fatigue	Agitation, Anxiety, & Irritability

Source: Mayo Clinic

The cause of winter-onset SAD is linked to a biochemical imbalance in the brain due to shorter daylight hours and reduced sunlight in winter. However, the triggers for summer-onset SAD are more intricate, with emerging evidence pointing to the role of air quality.

Causes of air pollution

While air quality is typically worse in winter, certain air quality issues accompany warmer weather, potentially contributing to spring/summer SAD.

1. **Wildfires:** Particle pollution levels can spike during the summer, particularly on the West Coast of the U.S., due to wildfires. Short-term exposure to particle pollution has been linked to psychiatric symptoms and increased hospitalizations.

2. **Ozone:** Ground-level ozone peaks in summer as sunlight reacts with pollutants, especially vehicle exhaust. Even low-level ozone exposure has been associated with depression in adolescents.

3. **Pollen:** Pollen allergies may increase susceptibility to non-winter SAD, as reported by individuals with pollen allergies.

Effects of air pollution

Both air pollution and pollen may elevate the risk of clinical depression, especially in spring-onset seasonal depression. One theory suggests that pollution and pollen trigger proinflammatory cytokines, proteins associated with the body's immune response and linked to depression. Another mechanism involves smaller particulate matter (PM2.5), which can penetrate the brain directly, causing structural changes and potentially contributing to depression.

How to prevent air pollution?

Indoor air purifiers, particularly those equipped with true HEPA filters capturing 99.97% of particle sizes, can help mitigate particulate matter and pollen. ActivePure Technology, integrated into many devices, not only neutralizes captured bacteria, mold, and viruses but also addresses contaminants present in the room.