Physical Research Laboratory (PRL), Navrangpura, Ahmedabad, 380009, India; Indian Institute of Technology Gandhinagar (IITGn), Gandhinagar, 382355, India.
Physical Research Laboratory (PRL), Navrangpura, Ahmedabad, 380009, India.
Chemosphere. 2020 Oct;256:127071. doi: 10.1016/j.chemosphere.2020.127071. Epub 2020 May 18.
The measurements of a monoterpene (α-pinene) were performed by the PTR-TOF-MS instrument at an urban site of India from mid-January to March 2014. The daytime concentration increased from 0.15 ppb in the second-half of January to 0.40 ppb in the second-half of March. Both the nighttime and daytime ratios of α-pinene/benzene in the second-half of March were 2-3 times higher their respective values from mid-January to first-half of February. The ratios of α-pinene/benzene increased from ∼0.27 ppb ppb at lower temperatures to ∼0.51 ppb ppb at higher temperatures indicating the increase of biogenic emissions in March. The concentration of α-pinene exhibited exponential decline with wind speed, but the rate of decrease in February was about twice that for March. The nighttime ratios of α-pinene/isoprene were greater than those measured in the daytime, suggesting temperature-dependent biogenic emissions of α-pinene. From mid-January to March, the increase of ∼53% in the biogenic contributions of α-pinene were associated with the change in meteorological conditions. Our analysis suggests that the combined effect of the northwest wind flow and higher air temperatures in March favored the emissions of BVOCs from local vegetation. The exceptionally high concentrations of α-pinene up to 6 ppb were measured during the Holi bonfire festival. This is the first study reporting the change in α-pinene during winter-summer transition over India. In the urban regions of developing countries, high emissions of BVOCs from vegetation and of NOx from anthropogenic sources can act as a source of ozone.
于 2014 年 1 月中旬至 3 月期间，在印度城市环境中使用 PTR-TOF-MS 仪器对单萜烯（α-蒎烯）进行了测量。日间浓度从 1 月下半月的 0.15 ppb 增加到 3 月下半月的 0.40 ppb。3 月下半月的 α-蒎烯/苯的夜间和日间比值均比 1 月中旬至 2 月上半月的相应值高 2-3 倍。α-蒎烯/苯的比值从低温时的约 0.27 ppb/ppb 增加到高温时的约 0.51 ppb/ppb，表明 3 月的生物排放增加。α-蒎烯的浓度随风速呈指数下降，但 2 月的下降速度约为 3 月的两倍。α-蒎烯/异戊二烯的夜间比值大于日间测量值，表明α-蒎烯的生物排放与温度有关。从 1 月中旬到 3 月，α-蒎烯的生物贡献增加了约 53%，这与气象条件的变化有关。我们的分析表明，3 月西北风的影响以及较高的空气温度有利于本地植被排放 BVOCs。在胡里节篝火庆典期间，测量到了高达 6 ppb 的α-蒎烯异常高浓度。这是第一项报告印度冬季-夏季过渡期间α-蒎烯变化的研究。在发展中国家的城市地区，植被排放的大量生物挥发性有机化合物（BVOCs）和人为来源的氮氧化物（NOx）可以成为臭氧的来源。
