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Aerosol number size distributions were measured continuously in Helsinki, Finland from 5 May 1997 to 28 February 2003. The daily, monthly and annual patterns were investigated. The temporal variation of the particle number concentration was seen to follow the traffic density. The highest total particle number concentrations were usu-5 ally observed during(More)
During the calendar years 1998–2002, 147 clear 8 nm diameter particle formation events have been identified at the SMEAR I station in Värriö, northern Finland. The events have been classified in detail according to the particle formation rate, growth rate, event starting time, different trace gas concentrations and pre-existing particle concentrations as(More)
The effect of displacement flow on the distribution of aerosol concentration was investigated in an industrial hall. According to the displacement ventilation principle, vertical upflow is accomplished by introducing fresh air, cooler than room air, into the occupied zone near floor level. The fresh air is introduced from low-velocity devices and heated by(More)
Out-of-hospital cardiac arrest (OHCA) has been previously associated with exposure to particulate air pollution. However, there is uncertainty about the agents and mechanisms that are involved. We aimed to determine the association of gases and particulates with OHCA, and differences in pollutant effects on OHCAs due to acute myocardial infarction (AMI) vs(More)
OBJECTIVES The influence of traffic and meteorological conditions on aerosol characteristics outdoors, the relationship between indoor and outdoor aerosol particles, and the pollutant transport indoors by means of a mechanical ventilation system were studied. METHODS Indoor and outdoor concentrations of fine-particle numbers were measured during the(More)
We investigated the time span and spatial scale of regional new particle formation (NPF) events in Finland and Southern Sweden using measured particle number size distributions at five background stations. We define the time span of a NPF event as the time period from the first moment when the newly formed mode of aerosol particles is observable below 25 nm(More)
In species that disperse by airborne propagules an inverse relationship is often assumed between propagule size and dispersal distance. However, for microscopic spores the evidence for the relationship remains ambiguous. Lagrangian stochastic dispersion models that have been successful in predicting seed dispersal appear to predict similar dispersal for all(More)
We have identified 147 clear 8 nm diameter particle formation events at the SMEAR I station in V ¨ arrï o, northern Finland during calendar years 1998–2002. The events have been classified in detail according to the particle formation rate, growth rate, event starting time, different gas phase species concentrations and pre-existing particle con-5(More)
We developed a simple model to calculate the regional deposited dose of submicron aerosol particles in the respiratory system. This model incorporates measured outdoor and modeled indoor particle number size distributions, detailed activity patterns of three age groups (teens, adults, and the elderly), semi-empirical estimation of the regional deposition(More)
The use of nanoparticles (NPs) in industry is increasing rapidly, but knowledge of the occupational health and safety aspects of NPs is still limited. This is because quantitative NP exposure levels are scarce, and the metrics to describe doses are unclear. This study presents one method for estimating workers' calculated regional inhalation dose of(More)