Tropospheric reactive odd nitrogen over the South Pacific in austral springtime

The distribution of reactive nitrogen species over the South Pacific during austral springtime appears to be dominated by biomass burning emissions and possibly lightning and stratospheric inputs. The absence of robust correlations of reactive nitrogen species with source-specific tracers (e.g., C2H2 [combustion], CH3Cl [biomass burning], C2Cl4 [industrial],210Pb [continental], and 7Be [stratospheric]) suggests significant aging and processing of the sampled air parcels due to losses by surface deposition, OH attack, and dilution processes. Classification of the air parcels based on CO enhancements indicates that the greatest influence was found in plumes at 3–8 km altitude in the distributions of HNO3 and peroxyacetyl nitrate (PAN). Here mixing ratios of these species reached 600 parts per trillion by volume (pptv), values surprisingly large for a location several thousand kilometers removed from the nearest continental areas. The mixing ratio of total reactive nitrogen (the NOy sum), operationally defined in this paper as measured (NO + HNO3 + PAN + CH3ONO2 + C2H5ONO2) + modeled (NO2), had a median value of 285 pptv within these plumes compared with 120 pptv in nonplume air parcels. Particle NO−3 was not included in this analysis of the NOy sum due to its 10- to 15-min sampling time resolution, but, in general, it was \u3c10% of the NOy sum. Comparison of the two air parcel classifications for NOy and alkyl nitrate distributions showed no perceivable plume influence, but recycling of reactive nitrogen may have masked this direct effect. In the marine boundary layer, the NOy sum averaged 50 pptv in both air parcel classifications, being somewhat isolated from the polluted conditions above it by the trade wind inversion. In this region, however, alkyl nitrates appear to have an important marine source where they comprise 20–80% of the NOy sum in equatorial and high-latitude regions over the South Pacific

Identification of pyrolysis products of the new psychoactive substance 2-amino-1-(4-bromo-2,5- dimethoxyphenyl)ethan-1-one (bk-2C-B) and its iodo analog bk-2C-I

2-Amino-1-(4-bromo-2,5-dimethoxyphenyl)ethanone hydrochloride (bk-2C-B) has recently emerged as a new psychoactive substance (NPS). It is most commonly consumed orally although there are indications that it might also be ingested by inhalation or ‘smoking’. Information about the stability of bk-2C-B when exposed to heat is unavailable and the potential for pyrolytic degradation and formation of unknown substances available for inhalation prompted an investigation using a simulated ‘meth pipe’ scenario. Twelve products following pyrolysis of bk- 2C-B were detected and verified by organic synthesis of the corresponding standards. In addition, 2-amino-1-(4-iodo-2,5-dimethoxyphenyl)ethanone hydrochloride (bk-2C-I) has been characterized for the first time and subjected to pyrolysis as well. Similar products were formed, which indicated that the replacement of the bromo with the iodo substituent did not affect the pyrolysis pattern under the conditions used. Two additional products were detected in the bk-2C- I pyrolates, namely 1-(2,5-dimethoxyphenyl)-ethanone and 1-iodo-4-ethenyl-5-methoxyphenol. The potential ingestion of pyrolysis products with unknown toxicity adds an element of concern

Carbonyl sulfide and carbon disulfide: Large-scale distributions over the western Pacific and emissions from Asia during TRACE-P

An extensive set of carbonyl sulfide (OCS) and carbon disulfide (CS 2) observations were made as part of the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) project, which took place in the early spring 2001. TRACE-P sampling focused on the western Pacific region but in total included the geographic region 110°E to 290°E longitude, 5°N to 50°N latitude, and 0-12 km altitude. Substantial OCS and CS2 enhancements were observed for a great many air masses of Chinese and Japanese origin during TRACE-P. Over the western Pacific, mean mixing ratios of long-lived OCS and shorter-lived CS2 showed a gradual decrease by about 10% and a factor of 5-10, respectively, from the surface to 8-10 km altitude, presumably because land-based sources dominated their distribution during February through April 2001. The highest mean OCS and CS 2 levels (580 and 20 pptv, respectively, based on 2.5° × 2.5° latitude bins) were observed below 2 km near the coast of Asia, at latitudes between 25°N and 35°N, where urban Asian outflow was strongest. Ratios of OCS versus CO for continental SE Asia were much lower compared to Chinese and Japanese signatures and were strongly associated with biomass burning/biofuel emissions. We present a new inventory of anthropogenic Asian emissions (including biomass burning) for OCS and CS2 and compare it to emission estimates based on regional relationships of OCS and CS 2 to CO and CO2. The OCS and CS2 results for the two methods compare well for continental SE Asia and Japan plus Korea and also for Chinese CS2 emissions. However, it appears that the inventory underestimates Chinese emissions of OCS by about 30-100%. This difference may be related to the fact that we did not include natural sources such as wetland emissions in our inventory, although the contributions from such sources are believed to be at a seasonal low during the study period. Uncertainties in OCS emissions from Chinese coal burning, which are poorly characterized, likely contribute to the discrepancy. Copyright 2004 by the American Geophysical Union