Air pollution is a growing health problem for urban populations
in emerging economies. The present study examines the (cross-
sectional) relation between blood pressure and particulate air
pollution in schoolchildren of Lahore (Pakistan). We recruited a
sample of 8–12year-old children (mean age 9.9years; 45% girls)
from two schools in Lahore situated in areas with low (n=79) and
high (n=100) air pollution, respectively. During the study
period (January-April 2009) particulate pollution [PM10 and
PM2.5i.e. particles with aerodynamic diameters below 10μm or
2.5μm, respectively] was measured at the school sites with a
laser operated device (Metone Aerocet 531). Blood pressure was
measured, after 5 minutes of sitting rest, using an automated
device (average of 5 consecutive measurements). Spot urine
samples were also collected and concentrations of Na and K were
measured. Mean daily values of PM2.5 were 28.5μg/m3 (SD: 10.3)
and 183μg/m3 (SD: 30.2), in the low and high pollution areas,
respectively. Systolic and di