Environ. sci. Technol. 1983, 17, 383-388
candidate for use by state and local agencies in the EPA IP network or by industry to meet monitoring needs. The unit has been found to have small c16 values to ensure windspeed independency. Computer analysis has shown that, for an urban mass distribution the inlet transmits 45.15 pg as compared to that collected in the thoracic region of the respiratory tract, 44.49 pg (4). (2) The unit was tested under off-mode (no flow rate) conditions and did not collect any detectable mass. (3) The unit was operated at &20° orientation to the mean flow. The effect on D50 was negligible. (4) The unit was operated at two different sampling rates in addition to the 4 cfm standard flow rate. At both 3.6 and 4.4 cfm, there was no significant change in the effectiveness values. (5) The inlet can be operated in the field for an indefinite period of time without any maintenance whatsoever. (6) The inlet collects virtually all mass in the inner tube as designed. (7) At this point in time, a D50 value has not been officially decided upon. This inlet design can, however, be modified to other realistic D50 values such as in the 6.07.5-pm range. (8) Consideration of possible particle reentrainment in the case of a “dirty” inlet has given rise to the concept of
a perfect absorber surface for the primary site of particle deposition. (9) A 40-cfm inlet and sampler have also been completed at this time. Both the herein described 4-cfm inlet and sampler and the 40-cfm unit are available through General Metal Works, Village of Cleves, OH 45002.
Literature Cited (1) Chan, T.L.; Lippmann, H. Am. Ind. Hyg. Assoc. J . 1980, 41,399-409. (2) Lee, R. E.,Jr.; Wagman, J. Am. Ind. Hyg. Assoc. J . 1966, 27,266-271. (3) Spicer, C. W.; Schumacher, P. M.;Kouyomjian, J. A. EPA Report No. EPA-600/2-78-06, 1978. (4) Wedding, J. B.;Carney, T. C. Atmos. Environ., in press. (5) Swift, D. L.; Proctor, D. F. Atmos. Environ. 1982,16,2279. (6) Robertson, J. M.;Wedding, J. B.;Peterka, J. A.;Cermak, J. E. J . Ind. Aerodyn. 1977,2, 345-359.
Received for review January 11, 1982. Revised manuscript received July 6,1982.Accepted January 3,1983. This work was performed under the auspices of the United States Environmental Protection Agency Cooperative Agreement No. 808011, with Ralph Baumgardner as Project Officer. This support is gratefully acknowledged.
Abastumani Forest Aerosol Experiment (1979): Comparison to Other Nonurban Halocarbons and Nitrous Oxide Measurements Dagmar R. Cronn,* W. Lee Bamesberger,+ and Valentln M. Koropalod Air Pollution Research Section, Department of Chemical Engineering, Washington State University, Pullman, Washington 99164, and Institute for Applied Physics. Moscow. USSR
w A joint U.S./USSR experiment conducted in July 1979 in the Caucasus Mountains of the USSR studied the relative contributions of biogenic emissions and long-range transport of anthropogenic pollutants to the aerosol burden of a remote atmosphere. To document any regional pollution buildup or long-range anthropogenic pollutant transport to the site, the levels of nitrous oxide and the (anthropogenic) trace gases CF2C12(F-12),CFC13 (F-ll), CH3CC13,and CCh were compared to a rural site in eastern Washington state. Diurnal patterns observed for each compound in the USSR and CC14 at the US. site were consistent with the local micrometeorology and the position of known local sources. Transport of anthropogenic gases to the study site was observed, but significant regional pollution buildup did not occur. The site was well chosen to meet the objectives of the study since it was shown to be relatively remote from anthropogenic influence with respect to the trace gases.
Introduction A cooperative field project was conducted at the Abastumani Geophysical Observatory in the Georgia Republic, USSR, during July 1979. The Abastumani Forest Aerosol Experiment (AFAEX) 1979 had participants from the United States including the Environmental Protection Agency (Environmental Sciences Research Laboratory, Research Triangle Park, NC, the Department of Civil Engineering, University of Washington, Seattle, WA, and t Washington State University.
Institute for Applied Physics. 0013-936X/83/0917-0383$01.50/0
the Washington State University (WSU) Air Pollution Research Section of the College of Engineering, Pullman, WA. Numerous Soviet laboratories also participated in the field study including the Main Geophysical Observatory, Leningrad, the Institutes of Atmospheric Physics and Applied Geophysics, Moscow, and the Institute of Physics, Vilnuis, Lithuania. The principal goal was to study the relative importance of biogenic emissions to the aerosol burden in remote atmospheres. WSU was responsible for collecting aerosol samples for individual organic component analysis by high-resolution mass spectrometry, for collecting aerosol samples for elemental analysis by X-ray fluorescence, and for ascertaining the extent to which anthropogenic emissions impacted the study site. This latter objective, to provide information on any long-range transport of anthropogenically polluted air masses to the study site, was met by operation of a continuous, automatic gas chromatograph with electron capture detection for analysis of the trace gases CFzClz (fluorocarbon-12 (F-12)), CFC13 (fluorocarbon-11 (F-ll)), CH3CC13 (l,l,l-trichloroethane),CCll (carbon tetrachloride), and N20 (nitrous oxide). The results of the organic analyses are reported in the following paper in this issue. Similar uses have been made of trace gases such as F-11, F-12, and CCll as indicators of transport of urban air masses ( I d ) . These trace gases are a good choice for characterizing anthropogenic contamination of the atmosphere because they are ubiquitous emissions of urban industrial areas and are chemically stable (lifetimes in years). The data collected during the Abastumani field study were interpreted relative to comparable data collected
0 1983 American Chemical Soclety
Envlron. Sci. Technol., Vol. 17,No. 7, 1983 383
Table I. Descriptive Statistics forthe USSR Halocarbon Data compd
mean
median
std dev 321 ppt 313 ppt 31 PPt (316 P P ~ ) " (313 PPtY (13 P P ~ Y F-11 186 ppt 184 ppt 7 PPt CH,CCl, 137 ppt 136 ppt 6 PPt CCl, 148 ppt 147 ppt 3 PPt 301 ppb N*O 2 PPb 301 ppb F-12 values excluding period when tank of F-12 was leaking nearhy. F-12
a
min
max
N
289 ppt (294 PPtY 168 ppt 120 ppt 141 ppt 292 ppb
601 ppt (396 pptY 234 ppt 156 ppt 182 ppt 315 ppb
574 ( 488)Q 630 632 626 519
Table 11. Descriptive Statistics for the Eastern Washington Data compd
mean
median
std dev
min
max
N
F-12 F-11 CH,CCl, CCl,
289 ppt 177 ppt 135 ppt 158 ppt 302 ppb
289 ppt 177 ppt 134 ppt 156 ppt 302 ppb
17 ppt 5 PPt 16 P P ~ 10 ppt 5 PPb
229 ppt 164 ppt 90 PPt 124 ppt 286 ppb
372 ppt 228 PPt 188 ppt 213 ppt 320 ppb
370 395 389 393 395
N2O
concurrently at a rural continuous monitoring site in eastern Washington state that has been in operation since July 1976. The Washington site data indicate the levels to be expected in relatively clean, remote air masses. The diurnal patterns observed at Abastumani are shown to be consistent with the micrometeorology of the locale and the position of local sources while the synoptic meteorological situation correlates with small changes in the anthropogenic gas levels. Anthropogenic influences were shown to be small, however, supporting the fact that the site selection met the objectives of the study. Despite the site being remote from significant anthropogenic influence with respect to the trace gases, the fine fraction of aerosols consisted mostly of sulfates (see the following paper in this issue). Experimental Methods Measurements were made between July 7 and 27,1979, a t Abastumani. During the first few days at the site (June 30-July 3), the instrumentation was installed and made ready for operation. The carrier gases and calibration gases arrived on July 7. The ambient mixing ratios of the five gaseous compounds were subsequently determined on a 40-min schedule. There is a nearly complete data record for F-12, F-11, CH3CC13,and CC14from July 7 to 27 and data for N20 from July 10, through July 27. Moreover, 29 whole-air canister samples were collected during the experiment and returned to Pullman for backup analysis. Details of the two sampling sites including maps are given as supplementary material (see paragraph at the end of the text). The halocarbons and nitrous oxide were measured on a continual basis by electron capture gas chromatography techniques. A schematic diagram of the system used a t Abastumani and a typical chromatogram accompany a detailed description of the instrumentation in the supplementary material. Discussion, tables, and figures concerning precision of measurement, detector sensitivity changes, and standardization techniques are also included in the supplementary material. A Soviet TsVET-110 gas chromatograph was also operated during the study period at Abastmani by personnel from the Institute of Applied Physics, Moscow. This instrument had a direct-current electron capture detector. Samples (2-5 L) were collected on a solid adsorbent (graphitic channel black) and heat desorbed at a rate of 200-300 mL min-l at 200 "C into the GC for analysis of the trace gases F-11,CH3CC13and CClk The stainless steel packed column was similar to the Chromosorb column used in the American instrument. The oven was held 384
Environ. Sci. Technol., Vol. 17, No. 7, 1083
F-ll 250
r I
I
ABASTUMANI
' 5 0 ' 1 ' 6 ' 9 ' 1 0 ' ~ ~ ' ~ 2 ' i ~ ' ~ 4 ' 1 5 ' 1 6 ' ~ 7 ' 1 8 ' 1 9 ' 2 0 ' 2 1 ' 2 2 ' 2 3 ' 2 4 ' 2 5 1 2 6 '
F3
250
g
200
I5O
z d 2 E A S T E R N WASHINGTON
DAY OF THE MONTH
(JULY, 1979 )
Figure 1. Fluorocarbon-11 mixing ratlo as a function of time for the Abastumanl and eastern Washington state sites.
isothermal at 55 OC and the detector at 270 "C. The nitrogen carrier gas flow rate was 60 mL mi&. An exchange of calibration gases between the Soviets and Americans was accomplished during the course of the study. Comparison of simultaneous measurements at 1000 local time on July 20 gave the following results: CC13F, 168 (IAP) and 178 ppt (WSU); CH3CC13,133 (IAP) and 135 ppt (WSU); CC14, 146 (IAP) and 144 ppt (WSU). These trace-gas components typically varied about 10% around these levels during the course of the project based on the IAP data.
Analytical Results The entire set of halocarbon and N20 data collected during the field study at Abastumani and the equivalent data set for the eastern Washington state site have been reported elsewhere (13). No nitrous oxide data were available at Abastaumani until July 10 because of start-up problems. Table I presents the average mixing ratios observed for the entire sampling period at Abastumani. Also, the means, standard deviations of the means, medians, maxima, and minima are shown along with the number of measurements included in the calculation of each mean. Comparable data for the eastern Washington site are presented in Table 11. In general, the canister data support the in-field results except for several high values in the canisters, which raise the averages and increase the variance substantially. Figure 1and supplementary Figures 5-8 (see paragraph at the end of the text regarding supplementary material)
Table 111. Comparison of Morning vs. Nighttime Averaged Mixing Ratios for Abastumani time compd perioda N mean std dev min max F-12 M 101 310 ppt 9 297 ppt 354 ppt N 387 318 ppt 13 294 ppt 396 ppt F-11 M 126 184 ppt 4 175 ppt 209 ppt N 504 187 ppt 7 168 ppt 234 ppt CH,CCI, M 126 136 ppt 7 120 ppt 153 ppt N 506 137 ppt 6 120 ppt 156 ppt cc1, M 125 147 ppt 3 141 ppt 157 ppt N 501 148 ppt 3 141 ppt 182 ppt M 111 300 ppb 2 N 408 301 ppb 2 M = morning (0800-1300), N = nighttime (1300-0800). N2O
-
292 ppb 296 ppb
T calcd
306ppb 315 ppb
>T
- 5.4
DF 486
- 4.5
628
0.0001
- 2.5
185
0.0116
-4.1
208
0.0001
-3.0
187
0.0033
prob
0.0001
303.0 T
n
0
302.5 302.0-
(3
5
xI 0 (u
2
W W
K
W
2
2
I
2
4g 6
8
I O g12 14
16 18, 20 22
5
p
~
1
8 0
0
~ 2
I 4
,
,I
6
8
contain plots of mixing ratios for both sites as a function of time during the monitoring period for N20, F-12, F-11, CC4, and CH3CC13,respectively. The differences in precision of measurement between the USSR and US. sites, due to differences in the frequency of standard runs, are obvious. The influence of the tank of F-12 gas, which was leaking about 100 m from the USSR sample inlet until July 11, is also obvious. Mean mixing ratios at the Abastumani study site as a function of hour of day during the monitoring period (excluding the F-12 values from the period when the tank of F-12 was leaking nearby) have been plotted with standard errors in Figures 2-4 and supplementary Figures 9 and 10. These figures show a clearly diurnal pattern for the halocarbon species. Two maxima occur, one a t nighttime and one in the afternoon, while the lowest levels occur between 0800 and 1300 local time for the four halocarbons. Nitrous oxide shows a broad daytime minimum and a maximum about midnight. Averages were calculated for the Soviet data from 0800 (local time) to 1300 (morning) and 1300 to 0800 (nighttime) for each component measured and for the US. data from 0800 (local time) to 2000 (daytime) and 2000 to 0800 (nighttime). These time periods were selected to coincide with the known micrometeorology of the sites (e.g., mountain/valley winds in the USSR) and the observed diurnal patterns of Figures 2-4 and supplementary Figures 9 and 10. Tables I11 and IV give the results of the morning/night comparisons for the USSR and the day/ night comparisons for the US. data, respectively. There is no statistically significant difference between night and day for F-11, F-12, CH3CCI3,or N20 at the site in Wash-
I
I
I
I
,
HOUR ( L T )
HOUR (LT)
Figure 2. Nitrous oxide mixing ratio mean with standard error as a function of hour of day.
,
IO 12 14 16 18 20 22
Figure 3. Fluorocarbon-I 1 mixing ratio mean with standard error as a function of hour of day.
(3
a
1 133
> a
132 0
2
4
6
8
IO 12 14 16
18
20 22
HOUR (LT)
Figure 4. 1,1,1-Trichloroethane mixing ratio mean with standard error as a function of hour of day.
ington. However, there is a definite difference for F-11, F-12, CH3CC13,CC14, and N20 at Abastumani and CC14 at Washington with the nighttime values being higher in each case. There was no similar day/night difference observed for any of the five compounds during a study in the Smoky Mountains of Tennessee conducted in Sept 1978 (1). Discussion and Conclusions
According to the description of the synoptic weather conditions during July 1979 ( 6 ) ,a major feature of this period was periodic deep penetration of cold polar air to Environ. Scl. Technol., Vol. 17, No. 7, 1983
385
Table IV. Comparison of Daytime vs. Nighttime Averaged Mixing Ratios for Eastern Washington compd F-12 F-11 CH,CCl,
cc1, N*O a
time perioda D N D N D N D N D N
meanb 288 ppt 291 ppt 177 ppt 177 ppt 133 ppt 135 ppt 155 ppt 161 ppt 302 ppb 303 ppb
std dev 11 8 2 4 9 11 3 6 2 3
min
max
Tcalcd
DF
prob> T
267 ppt 274 ppt 172 ppt 170 ppt 116 ppt 118 ppt 147 ppt 153 ppt 298 ppb 296 ppb
305 ppt 303 ppt 182 ppt 189 ppt 147 ppt 157 ppt 159 ppt 179 ppt 307 ppb 307 ppb
- 1.1
38
0.2915
- 0.3
38
0.7690
- 0.6
38
0.5630
- 3.8
38
0.0001
-0.2
38
0.8200
D = daytime (0800-ZOOO), N = nighttime (2000-0800).
the southern parts of the Soviet Union. Hence, abnormally cool weather was observed at Abastumani during the study period. The period of the experiment can be divided into subperiods. From July 3 to 9, the weather in the Transcaucasus was affected by a frontal zone. As a result, cool, cloudy, and rainy weather prevailed. The mountain and valley circulation was weakened. From July 9 to 11,relatively warm, dry air from the northern regions of Turkey and Iran spread into the Abastumani area along the southern periphery of a high-pressure region whose center was over the Stavropol region. During this period, the weather was fair with no precipitation. A mountain and valley circulation was observed. On July 11, a cold front passed through Abastumani followed by cool air. The weather was cloudy and rainy from July 11to 13. By July 14, the frontal zone had shifted, and the weather at Abastumani was again governed by a high-pressure region. The air temperature increased, whereas the relative humidity dropped. On July 16, another cold front passed through Abastumani, followed by moist air. On July 20, warm, moist air again arrived along the southern periphery of an anticyclone centered over the Stavropol region. There was a sharp increase in temperature and humidity. This period ended on July 23, when a cold front passed through Abastumani. The front governed the weather in this region to the end of the experiment. The frontal passage was accompanied by fog and thunderstorms with rain. A small cyclone passed through Abastumani on July 24 and 25, causing somewhat increased temperatures. On July 26, a cold front passed through the experimental area. The air temperature dropped sharply, and cloudy, rainy weather prevailed. This period was also characterized by increased thunderstorm activity. Despite the apparent influence of local sources (to be discussed subsequently), a comparison of the synoptic weather with the F-11 data does show generally higher F-11 values during periods when warm, dry air from Turkey and Iran was brought to the Abastumani area along the southern periphery of anticyclones in the Stavropol region. This is especially evident (see Figure 1)for the time periods on July 10-11, and 13-14. Such increases exist but are not as easily seen in Figure 1from July 21 to 23. In contrast, periods after cold fronts passed through Abastumani (when the weather was cool, cloudy, and rainy) had generally lower F-11 levels. These periods of lower F-11 values can be seen in Figure 1for July 7-9,ll-12,16-19, and 23-26. A Student’s t test showed that the F-11 levels were significantly lower during these cool periods than during the warm periods at the 99.99% confidence level. N20 does not show similar changes, and these changes are not seen as clearly in the F-12, CH3CC13,and CC14data. However, the general elevation of F-11 levels that occurred on July 13-14 also shows up in the CC14,CH3CC13,and F-12 data 386 Environ. Sci. Technoi., Vol. 17, No. 7, 1983
n = 20 in all cases.
sets. Likewise, the increases in F-11on July 10-11 can also be seen in the CC14 and CH3CC13traces (recall that the F-12 data were influenced by the leaking F-12 tank during this time). Again, Student’s t tests for F-12, CH3CC13,and CC1, showed significantly lower levels during cool periods compared to warm periods at the 99.99% confidence level. Since both sites are considered to be nonurban and are located at almost the same latitude, 42’ N and 47O N, the ambient levels of halocarbons and N20 were not anticipated to show significant differences during the same period. However, the Student’s t tests of the sample mixing ratios show that the US$R data are significantly different from the eastern Washington data for F-12, F-11, and CC14at the 99.99% confidence level. F-12 and F-11 were higher at Abastumani while CC14was higher in the US. There were no significant differences for N20 (probability > T = 0.82) and CH3CClS(probability > T = 0.043) although the situation for CHSCCl3was less clear-cut. The average level of CC14 observed at Abastumani is typical of the levels expected in remote background or free tropospheric air masses. The significantly higher average CCll levels at the eastern Washington site coupled with the significant day f night differences are understandable in terms of a local source of this trace gas near the sampling site. This local contaminating source has been an intermittent problem previously observed at this site. The diurnal patterns exhibited at Abastumani as seen in Figures 2-4 and supplementary Figures 9 and 10 were not anticipated prior to the study. Since considerable attention has been given to eliminating potential analytical explanations for such diurnal patterns (see supplementary material), one is left with the conclusion that the changes did indeed occur in the atmosphere. This implies that a local source of each of the five trace gases was influencing the sampling site during the study period and that the patterns observed were dictated by a combination of emission rates, source locations relative to the sample air inlet, and meteorological considerations. According to Vdovin (6),both the meteorological measurements made on the mountain and in the valley showed a well-defined daily variation of temperature, with a maximum at 1-3 p.m. and a minimum in the early morning hours. The daily variation of relative humidity was opposite to that of temperature. Water vapor pressure increased in the morning, with a slight minimum in the middle of the day due to increased turbulent exchange, and reached a second maximum in the second half of the day; in the evening, it decreased coincident with the temperature drop. As noted in the supplementary material, the data set has been corrected for changes in sample size caused by water vapor content in the sample loop. Correlation and regression tests were made of halocarbon mixing ratios vs. relative humidity, vapor pressure of water,
ambient temperature, and windspeed (6). F-12, F-11, and CH3CC13were significantly anticorrelated with temperature while F-12, F-11 and N 2 0 were significantly (positively) correlated with relative humidity. Generally, none. of the gases were significantly correlated with water vapor pressure or windspeed. These findings are understandable since the higher highttime levels are affected by smaller mixing volume under nighttime inversion conditions, when temperatyes are cooler and relative humidities are higher. In order to separate out the possible influence of slope winds, the winds were decomposed into notth-south and east-west vectors (6). At night and in the second half of the day, wind with a north component (mountain wind) prevailed, and it was only during the first half of the day that an evident, yet relatively weak, south flow was established. An east component was also observed in the morning, about 2 h after sunrise, when the southeast slopes of the Konobili mountain had warmed up. At night, a weak west component prevailed. This showed that the valley flow appeared a t 0800-0900, reaching a maximum a t 1000-1100. The mountain flow began soon after midday, reaching maximum speed at an altitude 200-300 m above the valley at 1700-1800. For local sources to have caused the average diurnal behavior observed at Abastumani requires that the mixing ratios be highest when winds were from the direction of the sources. All of the observatory buildings were north of the measurement site except two to the east. No buildings or other anthropogenic sources existed to the south or west of the measurement site. There is certainly a correlation between northerly winds at night and during the second half of the day and maxima in the diurnal patterns. Southerly or southeasterly winds in the morning correlate with the lowest average mixing ratios. To further substantiate the hypothesis of local-source influences on the trace-gas measurements at Abastumani, a simple Gaussian plume model with Turner/Pasqual stability parapeters was used to estimate what emission rates would be required to account for the observed elevations in mixing ratio of each trace gas. Since tee leaking tank of F-12 had been moved to a position estimated to be 1000 m north of the sample site (the opposite end of the observatory), this was treated as a point source. Stability class five (typical of clear, nighttime, low wind situations), wind velocity of 2 m s-l, and source height of 1 m were used. The model indicated about 32 ppt elqvation at Abastumani above the 290 ppt background of the Washington state site lo00 m downwind when the emission rate was 1 mg s-l or about 0.3 mL s-l. This is not an unreasonable emission rate for an F-12 tank that was observed to give levels that remained off scale on the GC for several hours at an attenuation of 4096 when a 5-mL sample of gas from near the cap of the tank was injected. For the same emission rate, the model also predicted about 1000 ppt 100 m downwind of the point source. This was just less than the estimated distance of the tank from the sample inlet prior to July 12, when the maximum mixing ratio observed was 600 ppt. Thus, the elevated average F-12 mixing ratios and diurnal pattern observed at the site can be explained by the identified local point source. CCl, a t Abastumani was elevated an average of about 3 ppt at night relative to morning values. An emission rate of 42 pg &500 m upwind would have gccounted for this observed diurnal difference. Large glass-stoppered bottles of CCl, were stored in a laboratory building about this distance to the north of the sampling site and this solvent was evidently being used in wet-chemical procedures associated with the AFAEX experiment. Measurements of
CCl, on a balcony of this laboratory building using the Soviet measurement technique copsiptently showed clearly elevated mixing ratios relatively to the levels being measured by the American technique a t the south end of the observatory. Thus, the loss of CC14from this building may have exerted the observed influence at the sampling site. The range in the average diurnal pattern of NzO at Abastumani was only about 2 ppb. The diurnal pattern differed from the four halocarbons. The values remained generally lower until abaut 1800 and peaked at about 2300. The diurnal pattern for N20 cannot be explained by diurnal changes in local soil emissions because the sample intake line at the site was at least 10 m above the ground. A potential N20 source was a building about 100 m east of the USSR gampling site. This building had a fireplace, which was used on most, but especially cool, evenings. Thk fireplace was the only one observed in use during the study period. Combustion sources have been reported to be sources of N20 (14,15). On one occasion the N20 mixing ratio was observed to be 314 ppb when the sample inlet line was directly in a visible smoke plume from the fire. Although the building was in use as a dentist’s office, an inquiry determined that laughing gas (N20)was not in storage or use in the building. The diurnal pattern is in keeping with the use of the fireplace in the evening and increased atmospheric stability in the evening. The average nighttime elevation of both F-11 and CH3CC13at Abastumani was about 5-7 ppt above \he daytime levels of 182 and 134 ppt, respectively. This would have required an emission rate of about 200 pg s-l at 1000 m upwind or 80 pg s-l at 500 m upwind to account for the observed mixing ratios. However, no sources of F-11 or CH3CC13 were identified anywhere at the observatory during the sample period. Correlation of the three ozone data sets (one US-operated instrument and two U$SR-operated instruments) were highly significant (p = 0.001). Therefore, only correlations to the U.S.ozone data set are reported in the following di$cussion (16). CH3CC13and CCl, were significantly positively correlated with ozone 0, = O.OOO1 &d 0.0033), and N20 was negatively correlated (p = 0.0160) while the positive correlations of ozone with F-12 and F-11 were not significant 0, = 0.1205 and 0.0777). The day/ night averages for ozone were different (p = 0.0146) with the daytime mean (45 ppb) higher than the nighttime mean (36 ppb). Thus the anticorrelation of N20 with ozone is not surprising since N20 nighttime values were slightly higher than the daytime level8 (Figure 2). Since CH3CC13 (Figure 4) and CCl, (supplementary Figure 10) were also slightly higher at night when ozone was lower, the positive correlation of these two compounds with Ozone must be caused by a more influential second mechanism, postulated to be the similar influence Qf synoptic meteorology acting on both ozone and the trace gases. The highest positive correlations (of ozone and CH3CC13followed by ozone and CCl,) caused by changipg synoptic conditions are sensible because the daylnight differences were least noticeable for these two compounds. The lack of significance for the positive correlation of F-11 (or F-12) with ozone which would be caused by similar behavior with changing weather conditions is offset by the signficant opposite diurnal behaviors exhibited by F-11 (or F-12) and ozone. None of the correlations of the five trace gases against ozone were statisticalIy significant when the data were first averaged on a 24-h basis in an attempt to eliminate the interpretation problem introduced by the diurnal variations, presumably partly becaused the number of observations drops to only 20 days. Envlron. Scl. Technol., Vol. 17, No. 7, 1983 387
Thus, we make the following conclusions: (1) Diurnal patterns of the various trace gases measured in this study are consistent with the micrometeorology of the sampling site and the position of local sources relative to t h e sampling site. (2) Apparent local emissions of the trace gases studied in this program complicate their use as tracers of long-range transport of anthropogenically influenced air masses. (3) However, F-11 levels (supported by similar behavior for F-12, CH,CC13, and CC14) increase when warm, dry air from Turkey and Iran influences the Abastumani Observatory, and F-11 levels are generally lower during cool, cloudy, and rainy periods. (4) Although some transport of these anthropogenic trace gases to the study site has been observed, which exceeds the generally clean levels (CC14excluded) observed in eastern Washington state, significant regional pollution buildup like that observed in the US.Smoky Mountains (1)is not a general feature of the atmosphere in the Caucasus Mountains of the USSR. (5) As a result, the site was well chosen for study of the relative impact on remote atmospheres of long-range transport of secondary anthropogenic particulate matter and natural biogenic aerosols. Indeed, although natural hydrocarbons were measured in the gas and aerosol phases at the study site, the predominant component of the fine aerosol fraction consisted of sulfates (see the following paper in this issue). Acknowledgments
David E. Harsch and Frederick A. Menzia helped ship the equipment to the USSR. Norman Ahlquist helped troubleshoot equipment malfunctions. Manana Turmanidze and Lali Bukhnikashvili assisted with on-site data reduction. Many helped unpack equipment, kept night watch, or helped change samples, including Sergey Zagoruyko and Saulos Arm&. Discussions about the experiment with G. V. Rosenberg and V. D. Stepaneko were well appreciated. Victor Nikohaskin and Galena Filatov assisted with the Soviet halocarbon measurements. Boris Vdovin supplied the synoptic weather summary and meteorological parameters. Tzu-Hua Victoria Tso helped with post-field-study data reduction and analysis. Brian Lamb kindly performed the Gaussian plume model calculations. S u p p l e m e n t a r y Material Available Thirteen sections will appear following these pages in the microfilm edition of this volume of the journal: (1)experimental methods; (2) supplementary Table I, precision of replicate measurements; (3) supplementary Table 11, secondary standard mixing ratios; (4) supplementary Figure 1, maps showing the study site at the Abastumani Geophysical Observatory in the Georgia Republic of the USSR; (5) supplementary Figure 2, schematic diagram of system for automatic, continuous monitoring of NzO, F-12, F-11, CH3CC1,, and CCl,; (6) supplementary Figure 3, a typical set of chromatograms for the Abastumani study site for June 13, 1979, at 0225 local time; (7) supplementary Figure 4, nitrous oxide standard peak height mean with standard error as a function of hour of day; (8) supplementary Figure 5, nitrous oxide mixing ratio as a function of time for the Abastumani and eastern Washington state sites; (9) supplementary Figure 6, fluorocarbon-12 mixing ratio as a function of time for the
388
Environ. Sci. Technol., Vol. 17, No. 7, 1983
Abastumani and eastern Washington state sites; (10) supplementary Figure 7, carbon tetrachloride mixing ratio as a function of time for the Abastumani and eastern Washington state sites; (11)supplementary Figure 8, l,l,l-trichloroethane mixing ratio as a function of time for the Abastumani and eastern Washington state sites; (12) supplementary Figure 9, fluorocarbon-12mixing ratio mean with standard error as a function of hour of day; (13) supplementary Figure 10, carbon tetrachloride mixing ratio mean with standard error as a function of hour of day (20 pages). Photocopies of the supplementary material from this paper of microfiche (105 X 148 mm, 24X reduction, negatives) may also be obtained from Distribution Office, Books and Journals Division, American Chemical Society, 1155 16th St., N.W., Washington, DC 20036. Full bibliographic citation (journal, title of article, author, page number) and prepayment, check or money order for $31.50 for photocopy ($33.50 foreign) or $6.00 for microfiche ($7.00 foreign), are required. Registry No. CF2C12,75-71-8; CFCIS,75-69-4; CHSCC13,7155-6; CC14, 56-23-5; nitrous oxide, 10024-97-2.
Literature Cited Cronn, D. R., presented at the Second Symposium on the Composition of the Nonurban Troposphere, Williamsburg, . . VA, May 1982. Hester, N. E.; Stephens, E. R.; Taylor, 0. C. J. Air Pollut. Control Assoc. 1974,24, 591-595. Jaffar, M.; Dutkiewicz, V. A.; Husain, L. Atmos. Environ. 1981,15, 1653-1657. Lovelock, J. E.; Maggs, R. J.; Wade, R. J. Nature (London) 1973, 341, 194-196. Simmonds, P. B.; Kerrin, S. L.; Lovelock, J. E.; Shair, F. H. Atmos. Environ. 1974, 8, 209-216. Vdovin, B. I., presented at the USSR-US. Data Exchange Meeting, Leningrad, USSR, Apr 1980. Rasmussen, R. A. Atmos. Environ. 1978, 12, 2505-2508. Rasmussen, R. A.; Pierotti, D. Geophys. Res. Lett. 1978, 5,353-355. Rasmussen, R. A.; Khalil, M. A. K. Atmos. Environ. 1981, 15, 1559-1568. Weiss, R. F. J. Geophys. Res. 1981, 86, 7185-7195. Connell, P. S.; Perry, R. A.; Howard, C. J. Geophys. Res. Lett. 1980, 7, 1093-1096. Goldan, P. D.; Kuster, W. C.; Schmeltekopf, A. L.; Fehsenfeld, F. C.; Albritton, D. L. J. Geophys. Res. 1981,86, 5385-5386. Cronn, D. R. EPA Report RO80403303-6, submitted to U. S. Environmental Protection Agency by Washington State University, Pullman, WA, 1980. Weiss, R. F.; Craig, H. Geophys. Res. Lett. 1976,3,751-753. Pierotti, D.; Rasmussen, R. A. Geophys. Res. Lett 1976,3, 265-267. Weiss, R. E., University of Washington, Seattle, WA, private communication, 1980. Received for review March 22,1982. Revised manuscript received January 28,1983. Accepted February 7,1983. Financial support for the U.S. participation was from the Regional Field Studies Office, William Wilson, Director, Environmental Protection Agency under Grant R0804033. AFAEX-1979 was a program conducted under the joint US.-USSR Agreement on Cooperation i n the Field of Environmental Protection within the framework of the working group 02.01-10, “Air Pollution Modeling, Instrumentation and Measurement Methodology”. The eastern Washington state site was supported by the National Aeronautics and Space Administration under Grant NSG-7214.
