Smoothed temporal patterns for 2-week averages of silicon based on CSN data collected at four sites co-located with NPACT fixed sites generally did not vary greatly when based on data collected every sixth day versus every third day at the same site, although a few local differences were evident (Figure 3).
Approach 1: Full spatiotemporal models combining the CSN/IMPROVE and NPACT data.
Approach 2: Simplified spatiotemporal models based on the NPACT data only.
EPA site data with those for EC and silicon based on fixed site NPACT data, we concluded that the patterns did not tend to be consistent enough to support using other pollutant data to generate full spatiotemporal models for [PM.
We explored the features of regulatory and NPACT monitoring data for EC and silicon relevant to our goal of combining all available exposure data in spatiotemporal prediction models to investigate health effects of long-term exposures to [PM.
We found inconsistencies between measurements from the NPACT and regulatory monitoring networks for both EC and silicon, even when both networks used the same filter analysis methods.
Differences between silicon measurements from co-located NPACT and CSN monitors placed a few meters away from each other might be driven by microscale local plume gradients.
5] component concentrations across the target cohort residences, the NPACT options were either to use the NPACT data alone or to combine the NPACT data with regulatory monitoring data.
NPACT epidemiologic study of components of fine particulate matter and cardiovascular disease in the MESA and WHI-OS cohorts.
Locations of CSN, IMPROVE, and NPACT monitoring sites for [PM.
Time-series plots of log-transformed (Ln) 2-week averages of silicon between every-3rd-day and every-6th-day measurements at the same four CSN sites co-located with four NPACT fixed sites in Chicago, Minneapolis- St.
3]) for the overlapping period from May 2007 through August 2008 between co-located CSN and NPACT fixed sites in each of six MESA city areas.