The toxicology branch of the disease control centers has a draft risk assessment that puts the safety level for medium-term exposure at three parts per billion.
Our results suggest that medium-term exposure to TRAP may induce an increased inflammatory/endothelial response, especially among diabetics and those not using statins.
For each air pollutant that was measured from stationary monitors, we considered the medium-term exposure windows of 1, 2, and 4 week moving average preceding each participant's examination.
In C. maenas, a reorganisation of gill epithelia was observed after short-term exposure to very high PCO2 (~4,340 μatm; 7 days), but not after medium-term exposure to high PCO2 (~2,270 μatm; 11 weeks) [ 36].
We compared the estimated effects of short- and medium-term exposure on mortality within cohort participants directly to estimated effects of long-term exposure on mortality within the same cohorts (Yap et al. 2012).
Three averaging periods were used for assessing short- and medium-term exposure: a 3-day average over the 3 days preceding the day of death; a 7-day average over the day of death and the preceding 6 days; and a 31-day average over the day of death and the preceding 30 days.
We also compared the estimated effects of short- and medium-term exposure with rate ratio estimates obtained from Poisson regression analysis of daily mortality within the general population from which the majority of cohort participants were selected (Beverland et al. 2007).
Bind et al. (2012) recently reported that short- and medium-term exposure to particle number, a measure of fresh traffic emissions, was positively associated with CRP and other markers of cardiovascular risk in a study of 704 highly selected elderly men.
Figure 2 summarizes the associations between PSS score and medium-term exposures measured from the stationary monitoring sites by season.
Table 4 summarizes the adjusted differences in PSS score and medium-term exposures to predicted PM2.5 and BC estimated from the spatio-temporal models.
There was also no indication of independent associations of hs-CRP with short- or medium-term exposures to PMALL or PMIND, whereas for PMTRA the positive association with hs-CRP increased with longer time windows of PMTRA exposure.
