We report the first measurements of both particulate and gas phase bromine in the Arctic troposphere. Data from continuous sampling of the Arctic aerosol over a period of 4 years (1976)(1977)(1978)(1979)(1980) indicate that the bromine content in the aerosol averages 6 + 4 ngBr/SCM (5 + 3 pptm Br) for 9 months of every year. During the 3-month period between February 15 and May 15, however, we observed an annual sharp maximum in particulate bromine with levels exceeding 100 ngBr/SCM (82 pptm Br). The Arctic aerosol showed no bromine enrichment relative to seawater except for this 3 month peak period. During the bromine maximum, enrichment factors reached 40 with average values near 10. Calculations of the amount of excess bromine in the Arctic aerosol showed that over 90% of the-peak bromine had an origin other than from direct bulk seawater injection. Total levels of gas phase bromine in the Arctic troposphere found during the peak aerosol period averaged 422 + 48 ngBr/SCM (118 + 14 pptv). Total bromine content during this period averaged 474 + 49 ngBr/SCM with gas-to-particle ratios ranging from 7 to 18. A measurement under nonpeak conditions showed total bromine levels at < 25 ngBr/SCM. The possibility that local contamination contributed to the seasonal development of the 3-month bromine peak was carefully considered and ruled out. Elevated particulate bromine levels, with peak values ranging from 22 to 30 ngBr/SCM, were also found at Ny-,&lesund, Spitsbergen (Norway). The apparent seasonal nature of this bromine peak suggests that the large bromine maximum observed at Barrow is not an isolated or unique phenomenon characteristic of that sampling location. The level of total bromine in the Arctic troposphere during the 3-month maximum was found to exceed all measurements made in the natural troposphere by up to an order of magnitude. When compared to the natural background levels, the results presented in this paper indicate that the bromine concentrations in the Arctic troposphere are the highest found anywhere in the world. Moyers and Duce, 1972a; Lovelock, 1975; Rahn et al., 1976; Singh et al., 1977, 1983-1. Smaller anthropogenic sources have been identified and include the production of (1) CH3Br, used as a soil fumigant; (2) tetrabromobisphenol-A, used as a flame retardant in printed circuit boards; (3) CF3Br, used as a fire retardant and refrigerant; and (4) C2H,•Br2, together with assorted brominated additives, used in automotive and other fossil fuels. The relative intensities of the various global sources of atmospheric bromine compounds, however, remain largely unknown. In addition, recent stratospheric measurements [-e.g., Sedlacek et al., 1979; Berg et al., 1980-1 have raised the possibility that one or more additional sources for atmospheric bromine near the earth's surface remain to be identified.

Abstract. Measurements are reported of four gas-phase, brominated organic species found in the Arctic atmosphere during March and April 1983. Volume mixing ratios for CH3Br, CH2BrCH2Br, CHBr3, and CH2Br2 were determined by GC/MS analysis from samples taken Arctic wide, including at the geographic North Pole and during a tropopause folding event over Baffin Bay near Thule, Greenland. Methyl bromide mixing ratios were reasonably constant at 11 + 4 pptv while the other three brominated organics showed a high degree of variability. Bromoform (2 to 46 pptv) was found to be the dominant contributor to gaseous organic bromine to the Arctic troposphere at 38 + 10% followed by CH2Br2 (3 to 60 pptv) at 29 + 6%. Both CH3Br and CH2BrCH2Br (1 to 37 pptv) reservoirs contained less than 20% of the organically bound bromine. Stratospheric samples, taken during a tropopause folding event, showed mixing ratios for all four species at levels high enough to support a stratospheric total volume mixing ratio of 249 pptv Br (888 ngBr/SCM).

A total halogen collection system employing ultra‐pure activated charcoal traps has been developed for use in the stratosphere aboard aircraft and balloon sampling platforms. Neutron activation techniques for low‐level chlorine, bromine, and iodine analysis within the activated charcoal sampling matrix were developed. Initial results from six aircraft flights and one balloon mission in the lower stratosphere are presented for latitudes ranging from 16°N to 67°N. Little variability was observed in twelve total, gaseous and particulate chlorine (Cltot) determinations as a function of latitude at 20 km with values ranging between 2.7 ± .9 ppbv and 3.2 ± .7 ppbv. Five total bromine (Brtot) values showed substantial variability ranging from 7 ± 4 pptv to 40 ± 11 pptv. No iodine was observed in any samples but a calculated Itot upper limit of < 3 pptv was determined.

We report the collection of stratospheric particles at 34-36 km using balloon-borne collectors. The concentration of particles on the collection surfaces and element concentrations were measured on the majority of the particles using scanning electron microscope (SEM) and proton-induced X-ray emission (PIXE) analysis respectively. Particle morphologies, elemental composition, and electron diffraction data were obtained on a small number of the collected particles using transmission electron microscope (TEM) techniques. The concentration of particles between 0.045 (lower imaging limit) and 1/tin in radius is several orders of magnitude above the blank levels on the collection surfaces while the concentration of particles above 1 #m is near blank levels. More than 106 submicron particles were collected. The concentration of submicron particles is between 10 and 50 times the concentration expected at the sampling altitude based on models using the measured flux of extraterrestrial particles to the atmosphere. The higher concentration of submicron particles may be due to contributions from volcanic particles, inaccuracies in the influx of particles of this size to the earth, or breakup of larger particles. Analysis of the elemental composition using PIXE showed C1, S, Ti, Fe, Br, Ni, Zr, Zn, Sr, and Cu in decreasing order of concentration. Elements below S could not be detected in the analysis. C1, S, and Br are believed to be present due to reaction of the collection surfaces and particles with atmospheric gases while the other elements are present in the particles. The elemental composition of the particles does not aUow an unequivocal origin to be assigned because particles from several of the possible sources listed above contain the measured elements. TEM analysis of 23 of the submicron particles showed 16 to be non-graphitic. The particles ranged from A1 rich silicates to almost pure Fe to one containing almost exclusively Ba and S. None were definitely chondritic in composition. This collection of particles complements existing collections obtained by aircraft. They were collected at much higher altitude and are predominantly submicron in size. Collection and analysis of particles at high altitudes using balloons presents unique challenges and opportunities in understanding the particle population in the stratosphere.

An intensive field sampling program has been carried out over the ocean in which 56 gas samples and 172 aerosol particle samples were analyzed for total organic chlorine and total inorganic chlorine gas and for particulate chlorine as a function of particle size. Sampling was conducted for 13-to 21-hour periods, March 5-14, 1976, 4 km from the north Florida shore of the Gulf of Mexico at 10-m and 2-m heights.Replicate samples collected simultaneously showed agreement within analytical errors generally of a few percent for gases and for the sum of particle size fractions. Over the course of the experiment, 21 ambient measurements of organic chlorine averaged 3050 ng Cl/m 8 STP of air, with a standard deviation of the distribution of measurements of 80 ng Cl/m 8 STP. Also in 21 measurements the sum of particulate and inorganic chlorine averaged 3030 + 190 ng Cl/m • STP. Thus the total chlorine concentration observed averaged 6070 + 220 ng Cl/m • STP, of which 50% was organic gaseous. In contrast, the proportion of inorganic gaseous chlorine varied drastically, ranging from one half to one hundred times the observed particulate chlorine concentration. The variation depended at least in part on whether cascade impactors with Nuclepore backup filters or filters alone were used for particle sampling before the airstream passed through treated LiOH-impregnated gas absorption filters and charcoal absorbers. The results suggest that rapid interchange occurs between inorganic gaseous and particulate chlorine in the atmosphere but that organic gaseous chlorine is relatively decoupled from these forms.