Regional Δ14C patterns and fossil fuel derived CO2 distribution in the Beijing area using annual plants

Abstract

The level of atmospheric Δ14C and the fossil fuel derived CO2 concentration in the Beijing area from May to September, 2009, were systematically analyzed based on radiocarbon (14C) measurements of annual plants by accelerator mass spectrometry (AMS). The results show that the maximum Δ14C in Beijing was 29.6‰±2. 2‰, and the minimum was -28.2‰±2.5‰, with a trend of decreasing Δ14C from the outer suburbs to inner suburbs to the urban center. This trend correlates well with increases in fossil fuel derived CO2 caused by human activities such as population density, industrial emissions and traffic, with lower values of atmospheric Δ14C associated with more intensive human activities. The fossil fuel derived CO2 concentrations from May to September, 2009, ranged from 3.9±1.0 ppm to 25.4±1.0 ppm. It was calculated that each additional 1 ppm of CO2 from fossil fuels depleted the atmospheric Δ14C by approximately 2.70‰. This study suggests that 14C measurements of annual plants by AMS provide an effective method to rapidly trace fossil fuel derived CO2. © 2011 The Author(s).