- 期刊
- OpenAccess
Evaluation of PM_(2.5) Surface Concentrations Simulated by NASA's MERRA Version 2 Aerosol Reanalysis over India and its Relation to the Air Quality Index
摘要
The PM_(2.5) (particulate matter with a diameter ≤ 2.5 μm), an essential component of air pollution, is closely linked to adverse effects on human health, including premature mortality following prolonged exposure. However, limited surface measurement and the lack of monitoring with adequate spatial resolution hamper studies related to air pollution and its impact on various societally relevant issues. More recently, the National Aeronautics and Space Administration (NASA)'s Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) has begun estimating the global distribution of PM_(2.5) mass concentrations at high spatio-temporal resolutions, but the limitations of the applied estimation methodologies must be carefully evaluated in order to understand their strengths and weaknesses. This study assesses MERRA-2's PM_(2.5) results by comparing them with ground-based measurements conducted at 20 stations across the Indian region between 2015 and early 2018. Our analysis shows that MERRA-2 generally underestimates the PM_(2.5) in terms of both the mass concentration and the number of exceedance days. While the Central Pollution Control Board (CPCB) measured exceedances of the national ambient air quality standards (NAAQS) on 34% of the days, MERRA-2's prediction was only 11%, and its estimate of the annual average PM_(2.5) concentration across all of the sites was also negatively biased, by ~27 μg m^(-3). Correlations of 0.96 and 0.6 were found between the estimates and the measurements for the monthly and the daily averaged concentrations, respectively; these numbers can be dramatically improved by applying a simple bias correction. Overall, our evaluation reveals that MERRA-2's raw estimates of PM_(2.5) on a monthly time scale or longer are helpful in long-term air quality studies.
延伸閱讀
- Sekiguchi, A., Shimadera, H., & Kondo, A. (2018). Impact of Aerosol Direct Effect on Wintertime PM_(2.5) Simulated by an Online Coupled Meteorology-Air Quality Model over East Asia. Aerosol and Air Quality Research, 18(4), 1068-1079. https://doi.org/10.4209/aaqr.2016.06.0282
- Lin, J., Shen, X., Xing, L., Che, H., & Holben, B. (2021). Analysis of Aerosol Type and Fine- and Coarse-mode Aerosol Direct Radiative Forcing over Regions in East and Southeast Asia Based on AERONET Version 3 Data. Aerosol and Air Quality Research, 21(7), 1-23. https://doi.org/10.4209/aaqr.200503
- Bilal, M., Nichol, J. E., & Spak, S. N. (2017). A New Approach for Estimation of Fine Particulate Concentrations Using Satellite Aerosol Optical Depth and Binning of Meteorological Variables. Aerosol and Air Quality Research, 17(2), 356-367. https://doi.org/10.4209/aaqr.2016.03.0097
- Sudheer, A. K., Rengarajan, R., Deka, D., Bhushan, R., Singh, S. K., & Aslam, M. Y. (2014). Diurnal and Seasonal Characteristics of Aerosol Ionic Constituents over an Urban Location in Western India: Secondary Aerosol Formation and Meteorological Influence. Aerosol and Air Quality Research, 14(6), 1701-1713(i-ii). https://www.airitilibrary.com/Article/Detail?DocID=16808584-201410-201411070001-201411070001-1701-1713(i-ii)
- Babu, S. S., Moorthy, K. K., & Satheesh, S. K. (2010). Vertical and Horizontal Gradients in Aerosol Black Carbon and Its Mass Fraction to Composite Aerosols over the East Coast of Peninsular India from Aircraft Measurements. Advances in Meteorology, 2010(), 480-486. https://doi.org/10.1155/2010/812075