生物质燃烧是大气氮氧化物(NOx)的主要来源,然而,生物质燃烧缺乏同位素指纹限制了它们在追踪大气硝酸盐(NO3-)和NOx中的使用。共收集了来自中国10个省区的25种生物质燃料,以及生物质燃料的δ15N值(δ15N-生物质)和生物质燃烧的δ15N-NOx值(BB的δ15N-NOx值,露天燃烧,和农村烹饪炉燃烧)进行了测定。露天燃烧和农村炊具燃烧的δ15N-NOx值范围为-0.8‰至11.6‰和0.8‰至9.5‰,分别,表明与δ15N-生物量呈显著线性关系。根据测得的BB和生物质燃烧排放清单数据的δ15N-NOx值,利用δ15N-NOx模型计算了中国不同省份和地区BB的δ15N-NOx值,平均值为5.0±1.8‰。中国BB的δ15N-NOx估计值的空间变化主要受中国各省区各种秸秆焚烧活动的δ15N-NOx值和NOx排放比例的差异控制。此外,通过使用生物质燃烧的局部排放与基于空气质量向后轨迹的NOx区域运输相结合,我们建立了改进的δ15N-NOx模型,并获得了更准确的地区BB的δ15N-NOx值(2.3‰至8.4‰)。通过利用中国21个城市的降水和颗粒物的δ15N-NOx值以及更准确的BB的δ15N-NOx值,来自四个来源的NOx贡献(移动来源,煤燃烧,生物质燃烧,和微生物氮循环)在全国范围内使用贝叶斯模型进行估计。揭示了生物质燃烧对NOx排放的显着贡献(20.9%至44.3%),这对于控制中国的NOx排放至关重要。
Biomass burning is a primary source of atmospheric nitrogen oxide (NOx), however, the lack of isotopic fingerprints from biomass burning limits their use in tracing atmospheric nitrate (NO3-) and NOx. A total of 25 biomass fuels from 10 provinces and regions in
China were collected, and the δ15N values of biomass fuels (δ15N-biomass) and δ15N-NOx values of biomass burning (δ15N-NOx values of BB, open burning, and rural cooking stove burning) were determined. The δ15N-NOx values of open burning and rural cooking stove burning ranged from -0.8 ‰ to 11.6 ‰ and 0.8 ‰ to 9.5 ‰, respectively, indicating a significant linear relation with δ15N-biomass. Based on the measured δ15N-NOx values of BB and biomass burning emission inventory data, the δ15N-NOx values of BB in different provinces and regions of China were calculated using the δ15N-NOx model, with a mean value of 5.0 ± 1.8 ‰. The spatial variations in the estimated δ15N-NOx values of BB in
China were mainly controlled by the differences in the δ15N-NOx values and the proportions of NOx emissions from various straw burning activities in provinces and regions of
China. Furthermore, by using the combined local emissions of biomass burning with regional transportations of NOx based on air-mass backward trajectories, we established an improved δ15N-NOx model and obtained more accurate δ15N-NOx values of BB in regions (2.3 ‰ to 8.4 ‰). By utilising the reported δ15N-NOx values of precipitation and particulate matter from 21 cities in
China and the more accurate δ15N-NOx values of BB, the NOx contributions from four sources (mobile sources, coal combustion, biomass burning, and microbial N cycle) at the national scale were estimated using a Bayesian model. The significant contributions of biomass burning (20.9 % to 44.3 %) to NOx emissions were revealed, which is vital for controlling NOx emissions in
China.