Contribution of terpenes to ozone formation and secondary organic aerosols in a subtropical forest impacted by urban pollution

• 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. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

BVOCs

Ozone formation

SOA mass analysis

TD-PTR-ToF-MS

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

terpene

tropical forest

urban pollution

volatile organic compound

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)