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PROPOSAL:

Preliminary Results from Multiple Air Toxics Exposure Study-II

SYNOPSIS:

In October, 1997, the Board approved the Multiple Air Toxics Exposure Study-II monitoring program as part of its Environmental Justice Initiatives. This major field effort, comprised of both fixed and mobile platforms sites, began in April 1998 and will conclude next month. Over six months of samples have now been analyzed and data have been compiled. Staff will provide a summary of the field program to date, and will conclude preliminary results of the data analysis. Final results are expected this summer.

Barry R. Wallerstein, D.Env.
Executive Officer

Background

In October 1997, the Board approved ten Environmental Justice Initiatives. Initiative No. 2 called for a major air toxics monitoring program, referred to as MATES-II (Multiple Air Toxics Exposure Study). This program is more comprehensive than a similar study conducted over a decade ago, in that more sites are being sampled and more toxic compounds are being analyzed. The current program includes two key elements: 10 fixed sites characterizing neighborhood-scale conditions over a one-year period; and a complementary microscale study using three mobile platforms to sample for one month at each of 14 additional locations. The microscale sites were selected to reflect potential localized influences of toxic-emitting sources near residential neighborhoods. In total, this monitoring program represents one of the most comprehensive air toxics monitoring programs ever conducted in a major urban area in the country, and is being recognized as a model program.

Sampling began in April 1998 and is scheduled to conclude at the end of March 1999. When concluded, over 2000 air samples will have been collected for analysis. Because of the nature and complexity of analyzing for toxic pollutants, both AQMD and ARB laboratories are cooperatively sharing the analytical burden. It takes at least two months after field samples are collected to complete the analyses, quality-check the results, and compile the data. To this point in time, the first six months of data have been tabulated.

Throughout the process, AQMD staff has been guided by a technical panel of experts. The Air Toxics Study Technical Review Group (ATSTRG), is comprised of 13 individuals representing academia, environmental groups, industry and private sector consultants, and governmental agencies, including ARB, EPA, and the state Office of Environmental Health Hazard Assessment. This group has been meeting on a monthly basis, and has helped guide the technical aspects of the program.

In addition to the field work, MATES-II also includes a comprehensive toxics emissions inventory update, including microinventories around each of the microscale sites. Both the field data and emissions inventories, when completed, will be input into appropriate computer models to map out toxics risk patterns across the entire Basin. 

Progress Report

The program, with all its complexities, has progressed quite smoothly. Some logistical difficulties have delayed the onset of some of the monitoring. To establish new monitoring locations, even for the mobile platforms, required considerable efforts in working with property owners, cities, and power companies. Licenses, license agreements, city permits, inspections, and other coordinated efforts often took weeks or, in some cases months, to achieve, even with expedited processing. As a result, the three new MATES-II sites (Huntington Park, Compton, and Wilmington) did not begin operations until June 1998 and July 1998, as opposed to April 1998 when sampling began at existing AQMD sites.

For the mobile platforms, despite logistical difficulties, it is expected that 13 of the 14 sites will be completed by the end of the MATES-II sampling in March 1999. The final microscale site will conclude monitoring before the end of April 1999. To date, sampling at both MATES-II and microscale sites have generated a wealth of new data.

Because of the keen public interest in this program, staff is presenting a progress report at this time. Since risk evaluations are based on annualized conditions, and because different compounds vary according to seasonal factors, summarized findings from a portion of the year are considered preliminary and non-conclusionary. However, to the extent that they provide insight into what is being measured in the atmosphere, staff believes it is important at this time to share the MATES-II preliminary compilations with the public (i.e., an oral presentation at the Board Meeting).

A final report is expected to be completed by the end of the summer, and staff will report back to the Board at that time.

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