Contribution of terpenes to ozone formation and secondary organic aerosols in a subtropical forest impacted by urban pollution
Journal
Atmosphere
Journal Volume
11
Journal Issue
11
Date Issued
2020-11-01
Author(s)
Salvador, Christian Mark
Chou, Charles C.K.
Ho, Tse Tsung
Tsai, Chao Yang
Tsao, Tsung Ming
Abstract
The highly reactive nature of biogenic volatile organic compounds (BVOCs) impacts the biosphere by acting as a precursor of ozone and aerosols that influence air quality and climate. Here, we assess the influence of BVOCs and their oxidation products on ozone formation and to submicron secondary organic aerosol (SOA) mass in a subtropical forest. A high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) was employed for the continuous measurement of VOCs. Isoprene, monoterpene, and sesquiterpene mixing ratios in the forest were 0.23, 0.22, and 0.03 ppb, respectively. The total ozone formation potential (OFP) of the terpenes was 12.8 μg m−3, which accounted for only 5.6% of the total OFP. Particle phase bound oxidation products were characterized using a thermal-desorption PTR-ToF-MS. Mass spectra analysis revealed the presence pinonaldehyde, pinonic, norpinonic, and pinic acid in both gas and particle phase. The overall daytime (nighttime) mixing ratio of the oxidized BVOCs in gas phases was 0.062(0.023) ppbv. On the other hand, the mean fraction of the four monoterpene oxidation products in condensed phase was estimated at 42%. Overall, the results of this study evidenced quantitatively the contribution of BVOCs to the total reactivity and SOA mass in the subtropical forest.
Subjects
BVOCs | Ozone formation | SOA mass analysis | TD-PTR-ToF-MS
BVOCs; Ozone formation; SOA mass analysis; TD-PTR-ToF-MS
Other Subjects
Aerosols; Air quality; Forestry; Inductively coupled plasma; Mass spectrometers; Mass spectrometry; Mixing; Monoterpenes; Oxidation; Proton transfer; Tropics; Volatile organic compounds; Biogenic volatile organic compounds; Continuous measurements; Oxidation products; Proton transfer reactions; Secondary organic aerosols; Subtropical forests; Time-of-flight mass spectrometers; Urban pollutions; Ozone; aerosol; mass spectrometry; oxidation; ozone; terpene; tropical forest; urban pollution; volatile organic compound
Type
journal article