The UFP concentrations (# cm3) were measured by means of
continuous monitoring using NanoTracer PNT 1000 (Philips
Electronics N.V., Netherlands) placed in the living room. The
NanoTracer counted particles in the range from 10 nm up to
300 nm. The UFP are defined as particles smaller than 100 nm,
thus also slightly larger particles than in the usual UFP cut-off of
100 nm were included. The UFP measurements consisted of
representative 24-h period. The PM2.5 concentrations were
measured using a cyclone sampling head GK 2.05-KTL (BGI
Incorporated, USA) powered by BGI 400 sampling pumps (BGI
Incorporated, USA) with a constant sampling rate of 4 l min1.
The pumps collected particles continuously over the entire study
period; however, the filters were changed after seven days.
Concentrations of PM2.5 were calculated as mg m3. Details of the
procedure are given in Ref.