Immediate effects of particulate air pollutants on heart rate and respiratory rate in hypertensive rats.

Time-series studies have shown that the lag time between elevated particulate air pollution (PM) and increases in cardiovascular-related hospital admissions and death is very short 1 d or less. If PM does cause serious cardiovascular effects shortly after exposure, one would expect to see some physiological change during exposure. In this study, spontaneously hypertensive rats (SHRs) with surgically implanted blood pressure transmitters were exposed to concentrated ambient PM (CAPS) for 4 h to determine whether CAPS inhalation causes immediate effects.