Biogenic emissions of isoprenoids and NO in China and comparison to anthropogenic emissions

• Published in: The Science of the total environment 2006-12, Vol.371 (1), p.238-251
• Main Authors: Tie, Xuexi, Li, Guohui, Ying, Zhuming, Guenther, Alex, Madronich, Sasha
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Applied sciences; Atmospheric pollution; China; Dispersed sources and other; Environmental Monitoring - methods; Exact sciences and technology; Models, Theoretical; Nitric Oxide - analysis; Ozone - analysis; Plants; Pollution; Pollution sources. Measurement results; Terpenes - analysis
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2006.06.025

In this study, a regional dynamical model (WRF) is used to drive biogenic emission models to calculate high resolution (10 × 10 km) biogenic emissions of isoprene (C 5H 8), monoterpenes (C 10H 16), and nitric oxide (NO) in China. This high resolution biogenic inventory will be available for the community to study the effect of biogenic emissions on photochemical oxidants in China. The biogenic emissions are compared to anthropogenic emissions to gain insight on the potential impact of the biogenic emissions on tropospheric chemistry, especially ozone production in this region. The results show that the biogenic emissions in China exhibit strongly diurnal, seasonal, and spatial variations. The isoprenoid (including both isoprene and monoterpenes) emissions are closely correlated to tree density and strongly vary with season and local time. During winter (January), the biogenic isoprenoid emissions are the lowest, resulting from lower temperature and solar radiation, and highest in summer (July) due to higher temperature and solar radiation. The biogenic NO emissions are also higher during summer and lower during winter, but the magnitude of the seasonal variation is smaller than the emissions of isoprene and monoterpenes. The biogenic emissions of NO are widely spread out in the northern, eastern, and southern China regions, where high-density agricultural soil lands are located. Both biogenic NO and isoprenoid emissions are very small in western China. The calculated total biogenic emission budget is smaller than the total anthropogenic VOC emission budget in China. The biogenic isoprenoid and anthropogenic VOC emissions are 10.9 and 15.1 Tg year − 1 , respectively. The total biogenic and anthropogenic emissions of NO are 5.9 and 11.5 Tg(NO) year − 1 , respectively. The study shows that in central eastern China, the estimated biogenic emissions of isoprenoids are very small, and the anthropogenic emissions of VOCs are dominant in this region. However, in northeastern and southern China, there are relatively large biogenic emissions of isoprenoids, leading to an important impact on the ozone production in these regions. Furthermore, the emissions of isoprenoids are highest during summer and noontime, which correlates to the peak of ozone production period. For example, the ratio between summer and winter for the emissions of isoprenoids is about 15 in China. As a result, the biogenic emissions of isoprenoids are significantly larger than the anthropogenic e