2008 Progress Report: Sources, Composition, Variability and Toxicological Characteristics of Coarse (PM10-2.5) Particles in Southern CaliforniaEPA Grant Number: R833743
Title: Sources, Composition, Variability and Toxicological Characteristics of Coarse (PM10-2.5) Particles in Southern California
Investigators: Sioutas, Constantinos , Cho, Arthur K. , Froines, John R. , Geller, Michael , Moore, Katherine F , Nel, Andre E. , Schauer, James J.
Current Investigators: Sioutas, Constantinos , Cho, Arthur K. , Froines, John R. , Moore, Katharine F. , Nel, Andre E. , Schauer, James J.
Institution: University of Southern California , University of California - Los Angeles , University of Wisconsin - Madison
EPA Project Officer: Chung, Serena
Project Period: November 1, 2007 through October 31, 2009 (Extended to October 31, 2012)
Project Period Covered by this Report: November 1, 2007 through October 31,2008
Project Amount: $1,120,641
RFA: Sources, Composition, and Health Effects of Coarse Particulate Matter (2006) RFA Text | Recipients Lists
Research Category: Air , Air Quality and Air Toxics , Particulate Matter
Objective:The objective of this study is to provide the much-needed information on the relationships between coarse particulate matter (PM) sources, spatial and seasonal characteristics, and toxicity in Southern California. The multidisciplinary research currently underway combines ambient measurements, exposure assessment and toxicology. The results of this study – the Los Angeles Basin (LAB) Coarse PM Study – will be integrated with other major research efforts currently under way in Southern California, including the EPA-funded Southern California PM Center.
During Year 1, the LAB Coarse PM Study performed the following tasks:
- Coordinated access to and received permission to sample at the 10 sampling sites identified for the study. This included identifying an appropriate alternate site for the indoor sampling study in the Long Beach area.
- Designed, assembled, tested and deployed to the field the 10 outdoor coarse PM samplers used to collect the filter samples that are the foundation of this project. Field deployment commenced in April 2008 (the end of Q2) and weekly collection of 24-hour integrated samples continued uninterrupted through the end of Q4.
- Designed, assembled, tested and deployed to the field the two different coarse PM samplers used to collect the indoor data. Phase I of the indoor sampling started in mid-July 2008 (Q3) and continued successfully for 9 consecutive weeks through early September 2008 (Q4) at two locations. Collection of a single 24-hour integrated weekly sample was matched with the operation of the adjacent/nearby outdoor coarse PM sampler.
- Following factory recalibration and testing at USC, three TEOM units modified to measure coarse PM only were deployed to sampling sites in Riverside, Lancaster and downtown Los Angeles to provide continuous hourly data. Deployment commenced in April (late Q2) and May 2008 (Q3) and measurements continued through the end of Q4.
- Detailed field maintenance sampling protocols were developed for the collection of both the integrated and continuous data for the regular weekly visit to each site.
- Supporting hourly air quality data (e.g. meteorological parameters) were obtained for each continuous coarse PM sampling site commencing in Q2 and continuing through Q4.
- The mass concentration of each filter was calculated on an on-going basis.
- Preliminary QA/QC was performed on both the continuous and time-integrated measurements based primarily on the mass concentration data reported for each filter. Comparisons between the continuous and time-integrated data also helped to identify problematic data. For the Q2 and Q3 filters, > 90% of all possible filters passed QA/QC and were submitted for chemical and biological analysis.
The preliminary integrated mass concentration results indicate that ambient coarse PM varies from as little as a few µg/m3 to more than 30 µg/m3 at the ten sites in the Los Angeles basin. Mean 24-hour coarse PM concentrations at all sites are typically 10 – 20 µg/m3. It is difficult to discern any particular trend in the integrated mass concentration observations as a function of the season thus far. The two Riverside area sites exhibit the highest 24-hour coarse PM mass concentrations on average. Concentrations at the western Los Angeles sites tended to be comparable from week-to-week. Meteorological factors may explain some of the inter-site consistency. More insight into the seasonal trends of coarse PM will be developed as the study progresses into the winter period in the Los Angeles Basin. The USC Coarse Particle Concentrator-derived coarse PM mass concentrations are slightly more variable from week-to-week than concentrations based upon the PCIS - coarse fraction. The coarse PM mass concentrations derived from both of these samplers were compared to each other at 9 of the 10 outdoor monitoring sites. Agreement in the coarse PM concentrations produced by these two samplers is very reasonable (within ca. 20% on average ) with PCIS concentrations typically lower.
Temporal and spatial coefficients of variation for the outdoor 24-hour integrated PCIS coarse PM mass concentrations are roughly comparable in range (approximately 20 – 40%). Higher mean COVs were observed in August and at the two Riverside/Mira Loma sampling locations. The same COV analysis for the USC Coarse Particle Concentrator yielded broadly similar results. The coefficients of divergence (CODs) were calculated using all of the coarse PM mass concentration data for paired sites. The median CODs were on the order of 0.3 – 0.4 suggesting that coarse PM integrated mass concentrations were moderately heterogeneous across the Los Angeles basin. There was no seasonal pattern discerned in the COD analysis, although as discussed earlier, a better insight into these trends will be developed once a full year of measurements is completed.
Continuous observations of coarse PM concentrations and additional supporting data at three sites indicate consistent daily patterns for stable meteorological conditions. At all sites, spikes in CO concentrations in the morning generally precede the daily increase in coarse PM concentrations. CO and NOx concentrations exhibited similar mean diurnal patterns. At the USC site (PIU), PM2.5 concentrations are greater than the coarse PM concentrations and the daily mid-day peak in PM10 concentrations is from the contribution of the coarse mode. By contrast, at the desert site of Lancaster (LAN), there is little difference between coarse PM and PM10 concentrations, indicating that in most instances PM2.5 is not important in this desert community. At the Riverside site of Van Buren (VBR), considerable additional continuous data are available from the three SCAQMD regulatory monitoring sites in the nearby communities. Interpretation of the VBR data is complicated by a local construction site, which likely represents a strong source of coarse PM during the day. At all 3 sites, meteorological conditions associated with the strong dry off-shore wind conditions known as “Santa Anas” are associated with sharply elevated coarse PM concentrations during some time periods in October. The COV and COD analysis of the continuous data yields more variable results than the 24-hour mean coarse PM concentration analysis did as time-averaging effects were mitigated.
During the indoor study conducted at two sites, the ratio of indoors to outdoors 24-hour integrated mass concentration measurements was 24% on average (range 14 – 35%) in eastern Los Angeles and 56% (range 24 – 94%) in Long Beach during phase one of the indoor study. More week-to-week and overall variability was observed in Long Beach.
The major objectives for the next reporting period of the LAB Coarse PM project are:
· Continue regular outdoor sample collection,
· Start and complete the second phase of the indoor sample collection study,
· Start the intensive sample collection study,
· Continue chemical analysis of the collected samples,
· Continue biological analysis of the collected samples,
· Continue data analysis
· Prepare and present preliminary results at technical conferences, and
· Begin and complete the first technical manuscripts to be submitted for peer reviewed publication.
The second phase of the indoor sample collection study will be performed during Q1/Q2 to obtain “winter” data to pair with phrase one summer data. The first phase of the intensive study will begin in Q3/Q4 to obtain “summer” data. Regular outdoor sample collection will be suspended as planned during the intensive study time period. Chemical and biological analyses, data analysis, the preparation of conference presentations and technical manuscripts will continue through all 4 quarters of Year 2.
Journal Articles:No journal articles submitted with this report: View all 21 publications for this project
Air pollution, ambient air quality, monitoring, environmental exposure, toxicology, human health, sensitive populations, environmental monitoring, air sampling, airborne particulate matter, chemical characteristics, chemical speciation sampling, source apportionment, quarter (Q). , RFA, Scientific Discipline, Air, particulate matter, Health Risk Assessment, Biology, atmospheric particulate matter, PM10, atmospheric particles, cardiopulmonary responses, human health effects, bioavailability, cardiovascular vulnerability, cardiotoxicity, coarse pm, exposure assessment