Characteristics and possible origins of atmospheric monoterpenes from nonliving plants in Guangzhou

Monoterpenes in ambient air were determined in various sites in Guangzhou, and it was revealed that monoterpene concentrations in some special sites, like landfills, were even higher than those in locations with much more vegetation. On the average, monoterpene contents in samples from streets and highways were 1.9 μg/m³; from gardens, plantations and wooded lands, 2.2 μ/m³; from farmlands, 1.5 μ/m³; but from landfills, 4.1 μ/m³. So other sources like landfills, apart from living plants, might also contribute to the biogenic non-methane hydrocarbons (NMHCs) in the atmospheric environment. On the other hand, the composition pattern of monoterpenes in air samples from landfills were obviously different compared with those from living plants, this might result from the different synthesis pathways of monoterpenes, the oxygen-depleted environment and the microbiogenic process might affect the synthesis in landfills.