气候变化领域集成服务门户(CCPortal): Direct measurement of aerosol acidity using pH testing paper and hygroscopic equilibrium under high relative humidity

CCPortal

DOI	10.1016/j.atmosenv.2021.118605
	Direct measurement of aerosol acidity using pH testing paper and hygroscopic equilibrium under high relative humidity
	Song Q.; Osada K.
发表日期	2021
ISSN	1352-2310
卷号	261
英文摘要	Acidity is a critical characteristic of aerosol particles that impacts many atmospheric chemical reactions. However, the measurement of aerosol acidity remains challenging because of the high ionic strength of atmospheric aerosol particles. In this study, we developed and evaluated a direct method for measuring the pH of atmospheric aerosol samples using pH testing paper. We first examined the color responses of six pH testing papers under various ionic strengths and selected the best performing paper for further testing at higher ionic strength. This paper was then tested under realistic high-ionic-strength conditions created using hygroscopic equilibrium under high and constant relative humidity (RH). A KNO3 saturated solution was used to maintain an RH of 92% in an airtight box. Under these conditions, the hygroscopic constituents in aerosol particles form droplets of aqueous solutions that possess high ionic strength. On the basis of these results, a method for the direct pH measurement of aerosol particle samples was developed. The pH of the atmospheric aerosol samples was measured using this method under high RH to demonstrate its versatility. Our results indicate that this method requires more than approximately 12 μg per spot of fine (PM0.2–2.0 in this study) particles to form a detectable droplet. Compared with previous methods, our direct pH measurement method is simpler, more convenient, and reliable for wide application without excess dilution in practice, and it may be used to obtain important basic information required to study atmospheric aerosols. © 2021
关键词	Aerosol acidity Hygroscopic equilibrium Ionic strength pH testing paper
语种	英语
scopus关键词	Atmospheric aerosols; Atmospheric humidity; Drops; pH; Potash; Potassium Nitrate; Aerosol acidity; Aerosol particles; Aerosol samples; High ionic strength; Higher relative humidity; Hygroscopic equilibrium; Measurements of; PH measurements; pH testing; Ph testing paper; Ionic strength; acidity; aerosol; detection method; measurement method; pH; relative humidity; testing method; acidity; aerosol; aqueous solution; article; controlled study; dilution; ionic strength; pH measurement; relative humidity
来源期刊	ATMOSPHERIC ENVIRONMENT
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/248316
作者单位	GSES, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
推荐引用方式 GB/T 7714	Song Q.,Osada K.. Direct measurement of aerosol acidity using pH testing paper and hygroscopic equilibrium under high relative humidity[J],2021,261.
APA	Song Q.,&Osada K..(2021).Direct measurement of aerosol acidity using pH testing paper and hygroscopic equilibrium under high relative humidity.ATMOSPHERIC ENVIRONMENT,261.
MLA	Song Q.,et al."Direct measurement of aerosol acidity using pH testing paper and hygroscopic equilibrium under high relative humidity".ATMOSPHERIC ENVIRONMENT 261(2021).