Earth, Atmosphere & Environment Sciences
Title : | Development of QCL-Based & Portable infrared spectrometer for measurements of HOND at atmospheric levels & probing HONO production in trace quantities in some laboratory reactions |
Area of research : | Earth, Atmosphere & Environment Sciences |
Focus area : | Atmospheric Science |
Principal Investigator : | Dr. Tapas Chakraborty Indian Association for the Cultivation of Science 2A & 2B Raja S. C. Mullick Road Jadavpur, Kolkata 700032 |
Timeline Start Year : | 2019 |
Timeline End Year : | 2022 |
Details
Executive Summary : | Hydroxyl radical (•OH) is known as the detergent of the earth’s atmosphere, and in the daytime more than 60% of the troposphere’s •OH is produced by photodissociation of atmospheric nitrous acid (HONO). It is believed that the main atmospheric source of HONO is the heterogeneous nighttime reactions of NO2, produced primarily via different anthropogenic activities, on wet surfaces. However, recent atmospheric modeling studies predict that there are missing sources of atmospheric HONO. Under the scope of this project, two new atmospheric production channels for HONO have been identified through laboratory investigations. Those are the reactions of gaseous NO2 with hydroxyacetone and glycolaldehyde, where both the latter two belong to the category of atmospherically significant volatile organic compound. The accumulated experimental data indicate that these reactions occur in the gas phase only, and not via heterogeneous surface reactions. In addition, under the project’s scope. a new gas phase reaction channel for the production of atmospheric nitric acid has been found where NO2 reacts with phenol, and the implication of the reaction has been analyzed thoroughly. A mobile quantum cascade laser-based spectrometer has been developed for the direct estimation of the atmospheric abundances of HONO. It is aimed that the spectrometer will be deployed at a suitable location in the near future. An alternative long path optical wave guide type apparatus has been developed, and which has been used to measure the atmospheric abundances of HONO in the premises of the Indian Association for the Cultivation of Science in the rainy season of 2019. The measured data is consistent with the reports of investigations carried out in the other parts of the world. |
Co-PI: | Dr. Prasant Singh Indian Association for the Cultivation of Science 2A & 2B Raja S. C. Mullick Road Jadavpur, Kolkata 700032 |
Total Budget (INR): | 1,00,89,600 |
Achievements : | (1) The QCL based mid-IR spectrometer has been developed and calibrated. Using this home-built spectrometer, we have already recorded high resolution infrared spectra of HONO in the spectral ranges of 1275.9-1276.3 cm-1 and 1276.3 to 1276.6 cm-1. (2) Further we have measured the concentration of HONO prepared in our laboratory. The detection sensitivity for determination of HONO concentration using this spectrometer is high enough, i.e., a concentration of less than 10 ppbv can be estimated. (3) Therefore, this QCL-based apparatus would be further used to quantify HONO production rates in various atmospherically relevant reactions by simulating those reactions in the laboratory. (4) Formation of HONO by hydration reaction of NO2 has been experimentally verified. And the yield of HONO at va |
Outcome/Output: | 2 publications
and 1 PhD produced |
Organizations involved