Associations of PM2.5 exposure with long COVID severity:insights from the P4O2 COVID-19 study

Long COVID, affecting 10-20% of COVID-19 cases, is characterized by persistent symptoms, including fatigue and dyspnea. The specific impact of exposure to fine particulate matter(PM_2.5) on the severity of long COVID is underexplored. This study aims to elucidate the relationships between personal and ambient PM_2.5 exposure and long COVID severity. The P4O2 COVID-19 study included 95 long COVID patients aged 40-65 years in the Netherlands and assessed lung function, fatigue, quality of life(QoL) and persistent symptoms 3-6 months post-infection. Personal and ambient PM_2.5 were measured in the participant’s homes and long-term ambient PM_2.5 exposure was estimated. Linear and logistic regression models analyzed associations between PM_2.5 exposure and markers for long COVID severity. Measurements were collected from 79 participants’ homes. The observed trends, while not statistically significant, appeared to be somewhat more pronounced for long-term ambient PM_2.5 exposure. After adjusting for individual-level confounders and pandemic characteristics, a 1µg/m³ increase in ambient PM_2.5 was associated with a -1.45%(95%CI:-9.85,6.95) decline in FEV1 predicted, a -0.07(95%CI:-0.18,0.04), decrease in QoL score and a 0.31(95%CI:-0.41,1.02) increase in fatigue scores. Adjusted ORs and 95%CIs for a 1µg/m³ increase in ambient PM_2.5 were 2.79(0.77-11.35) for respiratory symptoms and 2.23(0.69-8.20) for cardiovascular symptoms. While not statistically significant, the trends observed highlight the potential impact of PM_2.5 on shaping the progression of long COVID. Larger cohorts are necessary to validate these trends, ultimately contributing to targeted prevention and treatment strategies.