Assessment of Particulate Matter Levels in Vulnerable Communities in North Charleston, South Carolina prior to Port Expansion

Abstract

Introduction: The Port of Charleston, one of the busiest US ports, currently operates five terminals. The fifth terminal is being planned for expansion to accommodate container ships from the proposed Panama Canal expansion. Such expansion is expected to increase traffic within local vulnerable North Charleston neck communities by at least 7,000 diesel truck trips per day, more than a 70% increase from the present average rate of 10,000 trucks per day. Our objective was to measure the current particulate matter (PM) concentrations in North Charleston communities as a baseline to contrast against future air pollution after the proposed port expansion.

Methods: Saturation study was performed to determine spatial variability of PM in local Charleston neck communities. In addition, the temporal trends in particulate air pollution within the region were determined across several decades. With the BGI sampler, PM samples were collected for 24 hours comparable to the federal reference method protocol. Gravimetric analysis of the PM filter samples was conducted following EPA protocol.

Results: The range of the PM10 annual average across the region from 1982 to 2006 was 17.0-55.0 μg/m3. On only two occasions were the records of PM10 averaged above the 50.0 μg/m3 national standard. In the case of PM2.5, the annual average for 1999-2006 ranged from 11.0 to 13.5 μg/m3 and no annual average exceeded the 15.0 μg/m3 PM2.5 annual standard.

Conclusions: Although ambient PM levels have fallen in the Charleston region since the 1960s due to aggressive monitoring by the stakeholders against air pollution, local air pollution sources within the North Charleston neck communities have consistently contributed to the PM levels in the region for several decades. This baseline assessment of ambient PM will allow for comparisons with future assessments to ascertain the impact of the increased truck and port traffic on PM concentrations.

Keywords: air pollution; air quality; community; environmental justice; particulate matter; port; urban.

Figure 1

Charleston, SC peninsula indicating areas of port activity and SC ambient monitoring network sites. The blue dots represent air monitoring sites within the study communities. The red areas represent the study communities.

Figure 2

Air quality monitoring saturation study area: North Charleston and South Carolina (2008). Large yellow dots: current SCDHEC air monitoring stations; large green dots: planned project monitoring sites; small red triangles: air emission sites registered with SCDHEC; small yellow dots: discontinued ambient monitoring sites; small blue dots: Howard Heights saturation/FRM site.

Figure 3

Charleston seasonal windrose (2007).

Figure 4

Trend in annual PM₁₀ averages in Charleston across ambient monitoring stations (1980–2012).

Figure 5

Trend in annual PM_2.5 averages in Charleston across ambient monitoring stations (1998–2012).

Figure 6

Results of particulate matter saturation study for Charleston Neck communities in 2008.

Figure 7

Log-plot of geometric mean total suspended particulate concentrations from air quality monitoring stations in the Charleston metropolitan area, South Carolina (1968–2010).