Analysis of atmospheric hydrocarbons during winter MONEX

Abstract

The distribution of gaseous atmospheric hydrocarbon compounds, halocarbons, and nitrous oxide were studied. Whole air samples were collected aboard the NCAR Electra aircraft platform during the Monsoon Experiment (MONEX) flights in Kuala Lumpur, Malaysia, and on ferry flights to and from the United States. Foliage emission rates were also measured on some tropical plants. The average free tropospheric TNMHC (total non‐methane hydrocarbon) levels from both the transit flight and mission flights were low (2.5 μg/m3). TNMHC just above the forest canopy over Borneo but within the mixing layer was higher and the concentrations over land were higher than those obtained over the ocean. The fluorocarbons showed a small latitude gradient or a difference between continental and oceanic air masses or (possibily) both. Methyl chloroform also showed a significant latitude profile. Nitrous oxide was uniformly distributed in the atmosphere. The C2 hydrocarbons, ethane and acetylene, also showed latitudinal gradients. The emission rates of foliage in the tropics were higher than those reported by other investigators for the mid‐latitudes. The species sampled indicated that most tropical vegetation emits predominantly isoprene, rather than terpenes.

Volatile organic compounds from vegetation in southern Yunnan Province, China: Emission rates and some potential regional implications

“…Native palms Areca triandra and Rhapis excelsa also emitted high isoprene in branch enclosures. While Elaeis guineensis (Cronn and Nutmagul, 1982) and Rhapis humilis (Rasmussen, 1978) have been previously identified as isoprene emitters, we are aware of no previous isoprene emission measurements in the Areca, Calamus, or Salacca genera. However, our findings are consistent with the high fraction of isoprene emitting genera (19 of 23) and species (21 of 25) found within the palm (Arecaceae) family .…”

Analysis of atmospheric hydrocarbons during winter MONEX

“…Typically 500-1000 ml sample aliquots were used in the analysis. Other details of the analytical technique can be found elsewhere (Cronn and Nutmagul, 1980). The lower limits of detection of this method were 0.02 pg/m3…”

“…After at least a 5 to 10 minute flush of a canister with sample air, the container was pressurized to about 30 psia, to provide several liters of positive-pressure sample for analysis. The details of the sampling method are described elsewhere (Cronn and Nutmagul, 1980). A map of the individual flight tracks from Palo Alto to Kuala Lumpur (round trip) is shown in Fig.…”

“…The details of the sampling method are described elsewhere (Cronn and Nutmagul, 1980). Briefly, after plant selection, the Teflon bag enclosure was turned inside out, the unsealed edge was opened, and the bag alternately filled and deflated with ambient air to insure that any car exhaust components accumulated during transit were flushed out.…”

Air-quality and Climatic Consequences of Bioenergy Crop Cultivation

“…36,37 As many current and proposed bioenergy crops such as poplar (Populus), willow (Salix), oil palm (Elaeis guineensis) and Eucalyptus are significant emitters of isoprene, [38][39][40] large-scale land-use change associated with cultivation of these bioenergy crops has the potential to significantly impact regional atmospheric chemistry. 27 Recently, Ashworth et al 30 considered the air quality impacts of a global transition to biofuel crop cultivation, examining oil palm establishment in SE Asia and short rotation coppice species in North America; results from their modeling scenarios highlighted the potential negative impacts xi that widespread establishment of isoprene-emitting bioenergy crops may have on regional air pollution-regulation efforts.…”