Long COVID is an emerging medical condition defined by continuing symptoms reported by those who had previously recovered from COVID-19. The aforementioned symptoms impose significant effects on several physiological systems, especially the respiratory system. During the COVID-19 pandemic, several countries, including Thailand, encountered the issue of PM_(2.5) pollution, which has had adverse effects on human health. This study was to evaluate the impact of short-term exposure to PM_(2.5) on the respiratory system and its correlation with the prevalence of Long COVID, while also examining the relevant factors, particularly the presence of PM_(2.5) exposure. This Cross-Sectional analytical study was conducted with 694 participants who had recovered from COVID-19 in the northeast of Thailand. A generalized linear mixed model was used to identify the associations. It was found that the prevalence of Long COVID on the respiratory system: participants exposed to PM_(2.5) at 26-37 µg m^(-3). had an increased risk of developing Long COVID on the respiratory system at 50.54% (95% CI: 40.20-60.84), exposure to PM_(2.5) ≥ 1 hour per day (AOR = 1.84, 95% CI: 1.33-2.55, lived in urban areas (AOR: 1.64, 95% CI: 1.13-2.37), not wore a face mask to prevent PM_(2.5) exposure (AOR: 1.78, 95% CI: 1.25-2.54), female (AOR: 1.51, 95% CI: 1.05-2.18), farmer (AOR: 5.78, 95% CI: 1.05–2.18). The risk of exposure to PM_(2.5) is still at a level that affects health, and also affects Long COVID in many systems, especially the respiratory system. Therefore, risk groups and relevant agencies should use the study results as a prevention guideline to reduce the risk that may occur in each aspect of health. And there should be a process to prevent the risk of PM_(2.5) exposure.