Atmos. Chem. Phys. Discuss., 8, 9641-9672, 2008
www.atmos-chem-phys-discuss.net/8/9641/2008/
doi:10.5194/acpd-8-9641-2008
© Author(s) 2008. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Intra-community spatial variability of particulate matter size distributions in southern California/Los Angeles
M. Krudysz1, K. Moore2, M. Geller2, C. Sioutas2, and J. Froines1
1Center for Occupational and Environmental Health and the Department of Environmental Health Sciences, University of California, Los Angeles, CA 90095, USA
2Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, CA 90089, USA

Abstract. Ultrafine particle (UFP) number concentrations vary significantly on small spatial and temporal scales due to their short atmospheric lifetimes and multiplicity of sources. To determine UFP exposure gradients within a community, simultaneous particle number concentration measurements at a network of sites are necessary. Concurrent particle size distribution measurements aid in identifying UFP sources, while providing data to investigate local scale effects of both photochemical and physical processes on UFP. From April to December 2007, we monitored particle size distributions at 13 sites within 350 m to 11 km of each other in the vicinity of the Ports of Los Angeles and Long Beach using Scanning Mobility Particle Sizers (SMPS). Typically, three SMPS units were simultaneously deployed and rotated among sites at 1–2 week intervals. Total particle number concentration measurements were conducted continuously at all sites. Seasonal and diurnal size distribution patterns are complex, highly dependent on local meteorology, nearby PM sources, and times of day, and cannot be generalized over the study area nor inferred from one or two sampling locations. Spatial variation in particle number size distributions was assessed by calculating the coefficient of divergence (COD) and correlation coefficients (r) between site pairs. Results show an overall inverse relationship between particle size and CODs, implying that number concentrations of smaller particles (<40 nm) differ from site to site, whereas larger particles tend to have similar concentrations at various sampling locations. In addition, variations in r values as a function of particle size are not necessarily consistent with corresponding COD values, indicating that using results from correlation analysis alone may not accurately assess spatial variability.

Citation: Krudysz, M., Moore, K., Geller, M., Sioutas, C., and Froines, J.: Intra-community spatial variability of particulate matter size distributions in southern California/Los Angeles, Atmos. Chem. Phys. Discuss., 8, 9641-9672, doi:10.5194/acpd-8-9641-2008, 2008.
 
Search ACPD
Discussion Paper
    XML
    Citation
    Final Revised Paper
    Share