Solar and geomagnetic activity reduces pulmonary function and enhances particulate pollution effects

Increased solar and geomagnetic activity (SGA) may alter sympathetic nervous system activity, reduce antioxidant activity, and modulate physiochemical processes that contribute to atmospheric aerosols, all which may reduce pulmonary function.

Investigate associations between forced expiratory volume at 1 s (FEV₁) and forced vital capacity (FVC) with SGA, and assess whether SGA enhances adverse effects of particulate pollution, black carbon (BC) and particulate matter ≤2.5 μm in diameter (PM_2.5).

We conducted a repeated measures analysis in 726 Normative Aging Study participants (Boston, Massachusetts, USA) between 2000 and 2017, using interplanetary magnetic field (IMF), planetary K index (Kp), and sunspot number (SSN) as SGA measures. Linear mixed effects models were used to assess exposure moving averages up to 28 days for both SGA and pollution.

Increases in IMF, Kp Index and SSN from the day of the pulmonary function test averaged through day 28 of were associated with a significant decrement in FEV₁ and FVC, after adjusting for potential confounders. There were greater effects for longer moving averages and enhanced effects of PM_2.5 and BC on FEV₁ and FVC with increased SGA. For example, for each inter-quartile increase (4.55 μg/m3) in average PM_2.5 28 days before testing, low IMF (10th percentile: 3.2 nT) was associated with a -21.4 ml (95 % CI: -60.8, 18.1) and -7.1 ml (95 % CI: -37.7, 23·4) decrease in FVC and FEV₁, respectively; high IMF (90th percentile: 9.0 nT) was associated with a -120.7 ml (95 % CI:-166.5, -74.9) and -78.6 ml (95 % CI: -114.3, -42·8) decrease in FVC and FEV₁, respectively.

Increased periods of solar and geomagnetic activity may directly contribute to impaired pulmonary function and also enhance effects of PM_2.5 and BC. Since exposure to solar activity is ubiquitous, stricter measures in reducing air pollution exposures are warranted, particularly in elderly populations.