Indoor and Outdoor Nanoparticle Concentrations in an Urban Background Area in Northern Sweden: The NanoOffice Study

In recent years, nanoparticles (NPs) have received much attention due to their very small size, high penetration capacity, and toxicity. urban environments, combustion-formed (CFNPs) dominate in particle number concentrations (PNCs), exposure those particles constitutes a risk human health. Even though fine (<2.5 µm) are regularly monitored, information on NP concentrations, both indoors outdoors, is still limited. the NanoOffice study, of (10–300 nm) were measured outdoors with 5-min time resolution at twelve office buildings Umeå. Measurements taken during one-week period heating season non-heating season. The measuring equipment SMPS 3938 was used for indoor measurements, DISCmini outdoor measurements. highest offices close bus terminal lowest near park. addition, temporal effect appeared, usually higher found daytime background area, whereas considerably lower nanoparticle often present nighttime. Infiltration from air into also common. However, indoor/outdoor ratios (I/O ratios) NPs showed large variations between buildings, seasons, periods, I/O range 0.06 0.59. reasons infiltration rates could be emissions adjacent sources. We see growth since were, average, almost twice as outdoors. Despite relatively low nighttime, they rise local sources, infiltrated air.