Ultrafine particles exposure and early subclinical cardiovascular effects from shipping and port activities

Seaborne transport handles 80 % of goods across the world, producing 3 % of the world's greenhouse gases and other hazardous pollutants, among which are ultrafine particles (UFPs). The cardiovascular and pulmonary systems are the main targets of exposure to UFPs. Some studies highlight a possible role of airborne UFPs exposure in determining short-term subclinical effects, with alterations of heart rate variability (HRV) associated with autonomic dysregulation. We evaluated the concentrations, absorption doses and main sources of UFPs in Sardinian port areas, using two different methods of sampling: the characterization of UFPs by a stationary airborne particle sampling followed by a chemical characterization with a SEM-X-ray analysis, and a personal UFP exposure assessment by a portable particle counter. Finally, we evaluated the relationship between individual UFP exposure and heart rate variability (HRV) changes as an index of early subclinical cardiac effects in four healthy volunteers. The results from stationary samplings showed significant concentrations of airborne particles, primarily in the nanometre size range, with modes between 10 and 40 nm, characteristic of combustion sources. UFP concentration peaks often reached or exceeded 1 × 10⁵ part. cm^-3, with a peak of 7 × 10⁵ part. cm^-3, associated with the docking activities of ships. Chemical analysis revealed the presence of transition metal ions (vanadium, nickel, iron, manganese) and combustion products (carbon, oxygen, sulphur). The personal exposure data indicated that exposure to UFPs, measured as total particle dose (TPD), was significantly associated with short-term changes in HRV. Specifically, TPD had a significant association with parasympathetic nervous system (PNS) tone, decreasing it, and an opposite association with the sympathetic nervous system (SNS). Also, the size of UFP significantly associate with autonomic nervous system balance. The study concludes that people in port areas are exposed to UFPs from port activities and this exposure is linked to early HRV changes, due to autonomic dysregulation.