[1] Oxygenated volatile organic compounds (OVOC) can dominate atmospheric organic chemistry, but they are difficult to measure reliably at low levels in complex mixtures. Several techniques that have been used to speciate nonmethane organic compounds (NMOC) including OVOC were codeployed/intercompared in well-mixed smoke generated by 47 fires in the U.S. Department of Agriculture Forest Service Fire Sciences Combustion Facility. The agreement between proton transfer reaction mass spectrometry (PTR-MS) and open-path Fourier transform infrared spectroscopy (OP-FTIR) was excellent for methanol (PT/FT = 1.04 ± 0.118) and good on average for phenol (0.843 ± 0.845) and acetol ($0.81). The sum of OP-FTIR mixing ratios for acetic acid and glycolaldehyde agreed (within experimental uncertainty) with the PTR-MS mixing ratios for protonated mass 61 (PT/FT = 1.17 ± 0.34), and the sum of OP-FTIR mixing ratios for furan and isoprene agreed with the PTR-MS mixing ratios for protonated mass 69 (PT/FT = 0.783 ± 0.465). The sum of OP-FTIR mixing ratios for acetone and methylvinylether accounted for most of the PTR-MS protonated mass 59 signal (PT/FT = 1.29 ± 0.81), suggesting that one of these compounds was underestimated by OP-FTIR or that it failed to detect other compounds that could contribute at mass 59. Canister grab sampling followed by gas chromatography (GC) with mass spectrometry (MS), flame ionization detection (FID), and electron capture detection (ECD) analysis by two different groups agreed well with OP-FTIR for ethylene, acetylene, and propylene. However, these propylene levels were below those observed by PTR-MS (PT/FT = 2.33 ± 0.89). Good average agreement between PTR-MS and GC was obtained for benzene and toluene. At mixing ratios above a few parts per billion the OP-FTIR had advantages for measuring sticky compounds (e.g., ammonia and formic acid) or compounds with low proton affinity (e.g., hydrogen cyanide and formaldehyde). Even at these levels, only the PTR-MS measured acetonitrile and acetaldehyde. Below a few ppbv only the PTR-MS measured a variety of OVOC, but the possibility of fragmentation, interference, and sampling losses must be considered.

We report the evolution of the mixing state of black carbon (BC) particles in urban plumes measured by an airborne single particle soot photometer. The aircraft observations were conducted over the ocean near the coast of Japan in March 2004. The number fraction of coated BC particles with a core diameter of 180 nm increased from 0.35 to 0.63 within 12 hours (h), namely 2.3% h−1, after being emitted from the Nagoya urban area in Japan. BC particles with a core diameter of 250 nm increased at the slower rate of 1.0% h−1. The increase in coated BC particles was associated with increases in non‐sea salt sulfate and water‐soluble organic carbon by a factor of approximately two, indicating that these compounds contributed to the coating on the BC particles. These results give direct evidence that BC particles become internally mixed on a time scale of 12 h in urban plumes.

No abstract

Increasing atmospheric carbon dioxide (CO2) is the principal driver of anthropogenic climate change. Asia is an important region for the global carbon budget, with 4 of the world's 10 largest national emitters of CO2. Using an ensemble of seven atmospheric inverse systems, we estimated land biosphere fluxes (natural, land-use change and fires) based on atmospheric observations of CO2 concentration. The Asian land biosphere was a net sink of −0.46 (−0.70–0.24) PgC per year (median and range) for 1996–2012 and was mostly located in East Asia, while in South and Southeast Asia the land biosphere was close to carbon neutral. In East Asia, the annual CO2 sink increased between 1996–2001 and 2008–2012 by 0.56 (0.30–0.81) PgC, accounting for ∼35% of the increase in the global land biosphere sink. Uncertainty in the fossil fuel emissions contributes significantly (32%) to the uncertainty in land biosphere sink change.