Classified measurement method and system for atmospheric organic nitrate

Abstract

The invention discloses a classified measurement method and system for atmospheric organic nitrate, based on the characteristic that NO2 is generated through gradient pyrolysis of alkyl nitrate (ANs) and peroxy nitrate (PNs), a pyrolysis technology and a cavity enhanced absorption spectroscopy (CEAS) for measuring NO2 are combined, sampling gas is divided into three paths to pass through a normal-temperature channel, a medium-high-temperature channel and a high-temperature channel respectively and then enter a CEAS detection device in a regular and cycled way, absorption spectrum measurement of NO2, NO2 + PNs and NO2 + PNs + ANs in the atmosphere is realized, and the contents of NO2, PNs and ANs in the atmosphere are further obtained through spectral analysis. According to the invention, building of a measuring instrument system is realized through modular design, each module is independent, maintenance is easy, daily maintenance is simple, the energy consumption of the system is low, the instrument stability is high, the mechanical pressure resistance is strong, the volume is small, the weight is light, and the system is suitable for the online measurement of atmospheric organic nitrate in laboratory quantification and external field observation.

Description

technical field [0001] The invention belongs to the technical field of atmospheric gas monitoring, and relates to the classification and measurement of atmospheric organic nitrates (peroxynitrates and alkyl nitrates), in particular to a technique based on pyrolysis technology and cavity enhanced absorption spectroscopy (CEAS) The method and system for quantifying organic nitrates are suitable for online measurement of organic nitrates in laboratory experiments and field observations. Background technique [0002] Reactive nitrogen-containing compounds are an important class of trace gases in the atmosphere, closely related to the concentration distribution of oxidants in the atmosphere, and are key species that affect air quality and climate change. Nitrogen oxides in the atmosphere will generate organic nitrates during the chemical conversion process, which can be divided into peroxy nitrates (PNs) and alkyl nitrates (Alkyl nitrates, ANs) according to the difference in func...

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Problems solved by technology

The measurement technology based on gas chromatography can realize the quantification of single species, but there are problems such as low time resolution, timing calibration and the inability to obtain standard substances of some trace gases, which leads to the lack of total amount of organic nitrates.

Organic nitrates have the characteristics of gradient pyrolysis, and PNs and ANs will be pyrolyzed to produce NO at a suitable pyrolysis temperature 2 , the laser-induced fluorescence technique was first applied to pyrolysis-generated NO 2 It has the advantages of good sensitivity and high time resolution, but its application is limited due to high cost and complicated maintenance. Mass spectrometry also has a similar phenomenon.

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