Ambient concentrations and dosimetry of inhaled size-segregated particulate matter during periods of low urban mobility in Braganca, Portugal

• Autor(a) principal: Cipoli, Yago Alonso
• Data de Publicação: 2022
• Outros Autores: Targino, Admir Creso, Krecl, Patricia, Furst, Leonardo, Alves, Célia, Feliciano, Manuel
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10198/27476
• topic: Size-segregated particulate matter; Mobile monitoring; Lockdown; Exposure assessment; MPPD dosimetry model

The restrictive measures in place during the COVID-19 pandemic provided a timely scenario to investigate the effects of human activities on air quality, and the extent to which mobility reduction strategies can impact atmospheric pollutant levels. Real-time concentrations of PM1, PM2.5 and PM(10 )were measured using a mobile platform in a small city of Portugal, during morning and afternoon rush hours, in two distinct phases of the pandemic: emergency phase (cold period, lockdown) and calamity phase (warm period, less restricted). The Multiple-Path Particle Dosimetry Model (MPPD) was used to calculate the PM deposition for adults. Large spatiotemporal variabilities and pronounced changes in mean PM concentrations were observed, with lower concentrations in the calamity phase: PM1 = 2.33 +/- 1.61 mu g m(-3); PM2.5 = 5.15 +/- 2.77 mu g m(-3); PM10 = 23.30 +/- 21.53 mu g m(-3) than in the emergency phase: PM1 = 16.85 +/- 31.80 mu g m(-3); PM2.5 = 30.92 +/- 31.93 mu g m(-3); PM10 = 111.27 +/- 104.53 mu g m(-3). These changes are explained by a combination of meteorological factors and local emissions, mainly residential firewood burning. Regarding regional deposition, PM1 was the main contributor to deposition in the tracheobronchial (5%) and pulmonary (12%) regions, and PM10 in the head region (92%). In general, total deposition doses were higher for males than for females. This work quantitatively demonstrated that even with a 38% reduction in urban mobility during the lockdown, the use of firewood for residential heating is the main contributor to the high concentrations of PM and the respective inhaled dose.