4


Air Quality

I. BACKGROUND   §4.1

II. EXHAUST SYSTEM SAMPLING RESULTS   §4.2

Table 4-1: Most Significant Radionuclides Used

Table 4-2: US/EPA-Approved NESHAPs Compliance Strategy

Table 4-3: NESHAPs Building Exhaust Sampling and Monitoring Profile

Table 4-4: Summary of Radiological Air Emissions Released

Figure 4-1: Trends in Annual Tritium Releases from NTLF

III. AMBIENT AIR MONITORING RESULTS

A. Tritium   §4.3

Figure 4-2: Ambient Air Monitoring Network Sampling Locations

Table 4-5: Summary of Ambient Tritium Sampling

B. Gross Alpha/Beta   §4.4

Table 4-6: Gross Alpha and Beta Sampling Results from
                   Ambient Air Monitoring Network



§4.1      I. BACKGROUND

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

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.


Table 4-1      Most Significant Radionuclides Used*


Nuclide name
(atomic number)


Symbol

Principal radiation
types


Half-life

Carbon (6)

11C
14C

positron/gamma
beta

20.5 minutes
5730 years

Fluorine (9)

18F

positron/gamma

109.7 minutes

Hydrogen/Tritium (1)

3H

beta

12.28 years

Iodine (53)

123I
125I
131I

Gamma
beta
gamma

13.1 days
60.14 days
8.04 days

Nitrogen (7)

13N

positron/gamma

9.97 minutes

Oxygen (8)

14O
15O

positron/gamma
positron/gamma

71 seconds
122 seconds

*For a complete list of radionuclides evaluated under NESHAPs regulations, see Radionuclide Air
 Emission Annual Report for 1999, found on Berkeley Environmental Protection home page
 at http://www.lbl.gov/ehs/epg/html/env_protection.htm.


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:


Table 4-2      US/EPA-Approved NESHAPs Compliance Strategy



Compliance category

Annual effective dose equivalent*
(mSv/yr)



Sampling/monitoring strategy

Noncompliant

AEDE > 0.1

Reduce or relocate source term and reevaluate before authorization.

I

0.1 > AEDE > 0.001

Continuous sampling with telemetry to central computer for half-life less than 100 hours and weekly analysis for half-life greater than 100 hours. (US/EPA approval required to construct or modify.)

II

0.001 > AEDE > 0.0005

Continuous sampling with weekly analysis.

III

0.0005 > AEDE > 0.0001

Continuous sampling with monthly analysis.

IV

0.0001 > AEDE > 0.00001

Sampled annually during project activity.

V

0.00001 > AEDE

No monitoring required. Inventory controlled by administrative methods (Radiation Work Authorization/Permit).

*AEDE


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.


Table 4-3      NESHAPs Building Exhaust Sampling and Monitoring Profile


Monitoring type


Method


Location

Real-time

Real-time monitoring of 11C, 13N, and 15O

Bldg. 88 accelerator exhaust

 

Real-time monitoring of 11C, 13N, 15O, and 18F

Bldg. 56 Biomedical Isotope Facility
accelerator exhaust (2 locations)

Continuous

Sampling with weekly analysis

8 locations

 

Sampling with monthly analysis

12 locations

No monitoring

Inventory (administrative) control

96 locations


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.


Table 4-4      Summary of Radiological Air Emissions Released*


Nuclide

Total (Bq/yr)

% Total

H-3

1.15 ´ 10+12

90.2%

F-18

9.9 ´ 10+10

7.8%

C-11

2.22 ´ 10+10

1.7%

N-13

3.11 ´ 10+9

0.3%

O-15

2.22 ´ 10+8

0.0%

C-14

3.85 ´ 10+7

0.0%

I-125

1.21 ´ 10+7

0.0%

All others

3.15 ´ 10+5

0.0%

Total

1.28 ´ 10+12

100.0%

*For a complete list of radiological air emissions, see NESHAPs Annual Report for
 1999, found on Berkeley Lab’s Environmental Protection home page at
 http://www.lbl.gov/ehs/epg/html/env_ protection.htm.


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.

Figure 4-1      Trends in Annual Tritium Releases from NTLF

              III. AMBIENT AIR MONITORING RESULTS

§4.3      A. Tritium

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.

Figure 4-2      Ambient Air Monitoring Network Sampling Locations

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.


Table 4-5      Summary of Ambient Tritium Sampling




Station ID


Number of samples


Mean
(Bq/m
3)
a

Mean as percentage
of standard
b


Median
(Bq/m
3)


Maximum
(Bq/m
3)

ENV-B13A

12

< 0.19c

< 0.19c

<0.19c

ENV-B13C

12

< 0.19c

< 0.19c

< 0.19c

ENV-B13D

12

<0.41c

< 0.41c>

<0.41c

ENV-69

12

0.44

0.01

0.28

0.94

ENV-85

12

<0.19c

<0.19c

<0.19c

ENV-LHS

12

0.66

0.02

0.64

1.08

a1 Bq = 27 pCi
bStandard of comparison = 3.7 x 103 Bq/m3 (source: DOE Order 5400.5)
c Statistic was below the highest value for analytical sensitivity (minimum detectable amount) measured for this site.

§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:

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


Table 4-6      Gross Alpha and Beta Sampling Results from Ambient Air Monitoring Network



Analyte


Station ID

Number of samples

Mean
(Bq/m
3)
a

Median (Bq/m3)

Maximum (Bq/m3)

Alpha

ENV-B13Cb

11

<1.5 × 10–4

<1.5 × 10–4

2.3 × 10–4

 

ENV-69b

12

<1.1 × 10–4

<1.1 × 10–4

1.6 × 10–4

 

ENV-80b

12

<1.1 × 10–4

<1.1 × 10–4

2.2 × 10–4

 

ENV-81b

11

<1.1 × 10–4

<1.1 × 10–4

2.0 × 10–4

Beta

ENV-B13C

11

6.5 × 10–4

5.2 × 10–4

1.3 × 10–3

 

ENV-69

12

6.3 × 10–4

5.4 × 10–4

1.2 × 10–3

 

ENV-80

12

6.1 × 10–4

5.3 × 10–4

1.1 × 10–3

 

ENV-81

11

5.5 × 10–4

5.2 × 10–4

9.8 × 10–4

a 1 Bq = 27 pCi
b Both the mean and median of the results were below the highest value for analytical sensitivity (minimum detectable
   amount) for this site.