Non-methane hydrocarbons in a controlled ecological life support system

摘要

Non-methane hydrocarbons (NMHCs) are vital to people's health and plants' growth, especially inside a controlled ecological life support system (CELSS) built for long-term space explorations. In this study, we measured 54 kinds of NMHCs to study their changing trends in concentration levels during a 4-person 180 -day integrated experiment inside a CELSS with four cabins for plants growing and other two cabins for human daily activities and resources management. During the experiment, the total mixing ratio of measured NMHCs was 423 +/- 283 ppbv at the first day and it approached 2961 +/- 323 ppbv ultimately. Ethane and propane were the most abundant alkanes and their mixing ratios kept.growing from 27.5 +/- 19.4 and 31.0 +/- 33.6 ppbv to 2423 +/- 449 ppbv and 290 +/- 10 ppbv in the end. For alkenes, ethylene and isoprene presented continuously fluctuating states during the experimental period with average mixing ratios of 30.4 +/- 19.3 ppbv, 7.4 +/- 5.8 ppbv. For aromatic hydrocarbons, the total mixing ratios of benzene, toluene, ethylbenzene and xylenes declined from 48.0 +/- 44 ppbv initially to 3.8 +/- 1.1 ppbv ultimately. Biomass burning, sewage treatment, construction materials and plants all contributed to NMHCs inside CELSS. In conclusion, the results demonstrate the changing trends of NMHCs in a longterm closed ecological environment's atmosphere which provides valuable information for both the atmosphere management of CELSS and the exploration of interactions between humans and the total environment. (C) 2017 Elsevier Ltd. All rights reserved.