Enhancement effect of relative humidity on the formation and regional respiratory deposition of secondary organic aerosol

Yu, Kuo Pin; Lin, Chao; Yang, Shang Chun; Zhao, Ping

doi:10.1016/j.jhazmat.2011.04.042

Cited by 24 publications

(23 citation statements)

References 56 publications

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“…Besides, no matter if the NAI generator operated or not, the mass yield of SOAs increased with the increase of RH. The enhancement effect of RH on the formation of SOAs was related to the hygroscopic growth of SOAs, the gas-phase reaction between water and the excited Criegee intermediates that produced low-volatility products, and the formation of SOAs through aqueous chemistry taking place on the wet surface of the particles (Yu et al, 2011b).…”

Section: Resultsmentioning

confidence: 99%

“…To avoid the accumulation of the charge, the chamber was grounded. This experimental system (Figure 1) is a modification based on the system used in our recent research (Yu et al, 2011b), including the additions of an NAI generator and an aerosol neutralizer (model 3077A; TSI, St. Paul, MN). The aerosol neutralizer was used to neutralize the charged SOAs, and resultantly, to avoid the deposition of the charged SOAs in the sampling line.…”

Section: Methodsmentioning

confidence: 99%

“…In our previous study, we have proposed that k 2 is not particle size dependent in this size region (Zhao and Wu, 2006;Yu et al, 2011b); The time evolution of SOA concentration can be written as what follows (Yu et al, 2011b):…”

Section: Kinetics Modelmentioning

confidence: 99%

“…Therefore, it is necessary to validate the effectiveness of NAI generator on the deposition of ultrafine secondary organic aerosols (SOAs). In addition, some previous studies have shown that raising relative humidity (RH) can significantly enhance the formation of SOAs and increase both the mass and number concentrations (Jonsson et al, 2006;Huang et al, 2011;Yu et al, 2011b). In our study, we focused on the effect of RH on the deposition of aerosol particles enhanced by NAIs that was rarely discussed in previous studies.…”

Section: Introductionmentioning

confidence: 98%

“…(Alshawa et al, 2007;Waring et al, 2008). BVOCs will react with ozone and then generate secondary organic aerosols (SOAs) (Claeys, 2004;Chen and Griffin, 2005;Alshawa et al, 2007;Lee and Hsu, 2007;Sarwar and Corsi, 2007;Waring et al, 2008;Huang et al, 2011;Yu et al, 2011b;Bernard et al, 2012;Jonsson et al, 2006). Ultrafine particles may cause harmful health effects to human beings because they can penetrate deeply into the alveoli of lung or brain via neuronal translocation through olfactory nerves (Vallyathan and Gwinn, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Enhancement of the deposition of ultrafine secondary organic aerosols by the negative air ion and the effect of relative humidity

Yu¹

2012

Journal of the Air & Waste Management Association

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Deposition is an important process for the removal of aerosol particles. Negative air ion (NAI) generators can charge the ultrafine airborne particles and enhance their deposition rate. However, many NAI generators may also emit ozone and increase the concentration of particles in the presence of biogenic volatile organic compounds owing to the secondary organic aerosol (SOA) production. To validate the effectiveness of NAI generator, the authors investigated the enhancement effect of an NAI generator on the deposition of the ultrafine SOAs generated from the ozonolysis of d-limonene in a test chamber under controlled ventilation rate and relative humidity (RH). The experimental results demonstrated that compared with other effects, including the gravity, particle eddy diffusion, and the Brownian diffusion, the effect of NAIs is the most dominate one on the deposition of SOA particles onto the wall surface in the near-wall region (<1 cm away from the wall). According to these experiments, the tested NAI generator could efficiently enhance the deposition rate by an enhancement factor ranging from 8.17 AE 0.38 to 25.3 AE 1.1, with a low ozone production rate. This NAI generator had better performance on the deposition of the SOAs with smaller particle sizes and it performed even better under higher RH. The enhancement effect of the NAI generator was related to its high NAI production and electric field strength.Implications: This study investigated a novel technique of negative air ion (NAI) generator that can enhance the precipitation of nano-scale secondary organic aerosol (SOA). The tested NAI generator can significantly improve the deposition rate of SOA with an enhancement factor of about 8.17 AE 0.38 to 25.3 AE 1.1. The enhancement factor rose when relative humidity increased.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%