Decreased Human Respiratory Absorption Factors of Aromatic Hydrocarbons at Lower Exposure Levels: The Dual Effect in Reducing Ambient Air Toxics

Abstract

Respiratory absorption factors (AFs) are important parameters for assessing human health risks of long-term inhalation exposure to low-level hazardous air pollutants. However, it is uncertain whether previously measured respiratory AFs for high-level exposures could be directly applied. Here we measured real-time respiratory AFs using proton transfer reaction time-of-flight mass spectrometry for 50 subjects (20–30 years of age; 24 females and 26 males) exposed in a normal office room with aromatic hydrocarbons (AHs) at concentrations of several parts per billion by volume. The mean respiratory AFs of benzene, toluene, and C8-aromatics (ethylbenzene and xylenes) from all subjects were 28.2, 63.3, and 66.6%, respectively. No gender difference in the respiratory AFs of AHs was observed. Correlation analysis revealed that exposure concentration, rather than physiological parameters like body mass index or body fat ratio, was the dominant factor influencing the AFs of AHs. The results also demonstrated that respiratory AFs decreased in a logarithmic way when exposure levels of AHs were decreased. The decreased respiratory AFs at lowered exposure levels suggest the dual effect of reducing ambient air toxics like AHs with a decrease in human inhalation intake.

Vertical profiles of biogenic volatile organic compounds as observed online at a tower in Beijing

“…S1. The MDLs of isoprene and α-pinene were 58 and 64 pptV, respectively (Huang et al, 2017). It is worth noting that isoprene (m/z 69) may be overestimated due to interference from Furan and the fragmentation of 2-methyl-3-butene-2-ol (MBO) (de Gouw et al, 2003;Yuan et al, 2017).…”

“…Furthermore, wall adsorption and storage time may also influence the determination of BVOCs in bags and canisters samples (Ahn et al, 2016). In contrast, online instruments such as proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) overcome these shortcomings by offering real-time monitoring with a sample resolution on the order of seconds (de Gouw and Warneke, 2007;Liu et al, 2016;Huang et al, 2017;Yuan et al, 6 2017).…”

Mitigation of Secondary Organic Aerosol Formation from Log Wood Burning Emissions by Catalytic Removal of Aromatic Hydrocarbons

“…Harmful VOC emissions include aromatic, oxygenated aromatic, and polycyclic aromatic hydrocarbons (ArHC) . They are not only known to cause serious health issues in humans, through their carcinogenic effects (e.g., benzene is known to cause leukemia) or by deteriorating developmental, nervous, and heart and blood vessel systems, − but have also been identified as important SOA precursors in combustion emissions. ,,− Their relevance for ambient SOA formation is related to their reactivity toward hydroxyl radicals and the formation of low-volatility compounds upon only a few radical attacks, , which allows rapid condensation to the particle phase under typical atmospheric conditions. Additionally, incomplete WB leads to methane (CH 4 ) emissions. − These contribute relatively less to SOA formation owing to low SOA yields .…”

Observationally Constrained Modeling of Peroxy Radical During an Ozone Episode in the Pearl River Delta Region, China

“…Detailed laboratory analysis of OVOCs can be found elsewhere (Feng et al., 2004, 2005; Wu et al., 2021). In addition, other OVOCs, including methyl vinyl ketone (MVK) and methacrolein (MACR), methylhydroperoxide (CH 3 OOH), pyruvic acid, acetol, phenol, cresol, catechol, guaiacol, nitrophenol and methyl nitrophenol, were measured with a proton transfer reaction time‐of‐flight mass spectrometer (PTR‐TOF‐MS) (Model 2000, Ionicon Analytik GmbH, Austria) operated in H 3 O + mode at a time resolution of 10 s. The calibration and quality assurance of PTR‐TOF‐MS can be found elsewhere (Z. H. Huang et al., 2016, 2017; H. N. Zhang et al., 2020). The hydrocarbons and OVOCs measured in this study are listed in Table 1.…”