Berkeley Lab’s air monitoring program is designed to meet the following set of requirements:

• 40 CFR Part 61, Subpart H (NESHAPs)¹;
  
• DOE Order 5400.1 (General Environmental Protection Program)²; and
  
• DOE Order 5400.5 (Radiation Protection of the Public and the Environment).³

NESHAPs and DOE Order 5400.5 authorize monitoring requirements for radiological air emissions, while DOE Order 5400.1 includes additional requirements for nonradiological air emissions.

Under present requirements, Berkeley Lab’s air quality program measures only radiological components. Estimates of nonradiological air emissions use alternative methodologies (e.g., engineering calculations, record-keeping, and dose/risk modeling) to satisfy regulatory requirements. The comprehensive Environmental Monitoring Plan⁴ describes the basis and current scope of the air monitoring program at the Laboratory.

The air monitoring program consists of two separate elements: exhaust emissions monitoring and ambient air surveillance. Emission monitoring measures airborne contaminants in building exhaust systems (e.g., stacks). Ambient air surveillance measures air contaminants in the outdoor environment.

Ambient air surveillance results alone cannot distinguish between Berkeley Lab, non-Berkeley Lab, and natural background emission sources. When combined with exhaust emissions monitoring results and local meteorological information, however, ambient air surveillance results can sufficiently characterize the environmental impact of Laboratory activities. The number and placement of monitoring stations, as well as the parameters monitored and their frequency, are routinely reviewed to account for changes in Laboratory operations or external requirements.

§4.2      II. EXHAUST SYSTEM SAMPLING RESULTS

Berkeley Lab uses various radionuclides in its radiochemical and biomedical research programs. In addition, radioactive materials are generated from the operations of charged particle accelerators. Radionuclide releases from on-site building exhaust systems are usually in the form of vapor or gas. Releases in solid form as particulate matter are the least common form.

Table 4-1 contains the names and decay characteristics of the most significant radionuclides used at Berkeley Lab. Radioactive gases produced by accelerator operations are mainly short-lived radionuclides, such as carbon-11, nitrogen-13, oxygen-15, and argon-41.

The NESHAPs regulations require source measurement if the potential dose, or exposure over time, from emissions exceeds 1.0 ´10^-3 mSv/yr (0.1 mrem/yr).¹ As discussed in §3.7, Berkeley Lab uses a comprehensive tiered strategy approved by US/EPA to satisfy this requirement. See Table 4-2. This strategy involves three distinct levels of assessment:

• Real-time monitoring. Sophisticated monitoring systems that provide measurements in real time.
  
• Continuous sampling. In-line instrumentation for collection of time-integrated air samples that undergo laboratory analysis following US/EPA-approved protocols.
  
• Administrative controls. Strict administrative limits on radionuclide inventories combined with emission estimates.

The number and location of sources under each assessment category change in response to the research at Berkeley Lab. All but one source are considered “small sources” of emissions under NESHAPs. A large majority fall into compliance assessment Category V, which requires no monitoring. The 96 sources in this group adhere to strict inventory limits specified in individual work authorizations. Twenty locations use continuous sampling, including the only compliance Category I source on-site (the tritium stack at Building 75). Three locations have more rigorous real-time monitoring systems to estimate emissions with radionuclide half-lives that are less than 100 hours. Table 4-3 lists the breakdown of source assessment by category for the reporting year.

The stack monitoring program analyzed emission samples for five radiological parameters in 1999: gross alpha, gross beta, carbon-14, iodine-125, and tritium. As in past years, tritium in the form of tritiated water vapor was the predominant radionuclide emitted from Berkeley Lab activities. Tritium emissions totaling 1.15 × 10¹² Bq (31.2 Ci) were measured during the year, with nearly all tritium emitted from the National Tritium Labeling Facility’s (NTLF) exhaust stacks. Table 4-4 provides the list of the most significant radionuclide air emissions from site activities for the year. For information on the projected dose from all radionuclide emissions, see Chapter 9.

Tritium emissions for 1999 continue to be below regulatory levels of concern. The NTLF annual emission of 1.11 × 10¹² Bq (30 Ci) was below both the five- and ten-year averages for that facility. In fact, the total annual emissions were less than one-third of US/EPA’s reportable quantity for a singular release of tritium of 3.70 × 10¹² Bq (100 Ci).⁵ For information on trends in annual tritium releases from NTLF, see Figure 4-1.

Berkeley Lab determined levels of airborne tritium in the environment in 1999 at six monitoring sites. Three of the locations were on-site and three were off-site, as seen in Figure 4-2. The sites were chosen based on emission source locations, local wind patterns, and proximity to off-site residential areas and facilities. Equipment at each site continuously samples outdoor air. The sampling media are replaced and analyzed monthly.

Table 4-5 summarizes the network’s atmospheric tritium concentrations for the year. Average and maximum concentration values are far below 1% of the allowable DOE annual exposure standard for tritium in air.⁶ The most recent ambient air results for the network are down from the previous year and well below levels measured as recently as 1995. For example, the annual average concentration at the highest reporting station for 1999, ENV-LHS, was 0.66 Bq/m³ (16 pCi/m³). The highest annual average concentration for 1995, measured at adjacent sampling location ENV-69, was almost 40 times as large: 24 Bq/m³ (650 pCi/m³). Both sites are located near the main source of tritium at the Laboratory and comparable distances from the point of tritium release.

§4.4      B. Gross Alpha/Beta

The ambient air sampling network also included stations designed to sample air particulate for measuring gross alpha and gross beta levels. This network complements the exhaust system sampling program discussed in §4.1. The network consists of four monitoring sites: three sites on the main grounds of the Laboratory and a fourth site at the monitoring program’s most remote station, ENV-B13C. As with tritium sampling, the samplers draw air past collection media at a constant rate, with the media replaced monthly and samples analyzed by certified laboratories.

A fifth station was added briefly to detect any sign of radioactive contamination from a nuclear accident in Japan at the end of September. Sampling equipment set up for this investigation was identical to that found elsewhere in the network. In this case, sampling media were replaced and analyzed daily. No sign of a radioactive plume was detected in any of the five samples collected during the period when the plume was predicted to reach the west coast of North America.

Table 4-6 summarizes gross alpha and beta results from routine sampling activities in 1999. Although DOE Order 5400.5 does not provide a standard for particulate gross alpha and beta radiation, several observations about these results are apparent:

• They are extremely low, approaching or remaining below the analytical detection limits for each parameter;
  
• There is little variability from station to station, including station ENV-B13C located over 1.0 kilometer (0.6 mile) south of the site; and
  
• The results for each parameter change very little from one year to the next.

These observations indicate that environmental impacts from the Laboratory’s radioactive releases of alpha- and beta-emitting isotopes to the atmosphere are negligible.