Minimum R Squared Method (MRS)

***Please install Igor Pro first before you can run these programs.

Igor Pro 6.x download: https://www.wavemetrics.com/support/demos.htm

Minimum R Squared Method (MRS) initially proposed by Millet et al. (2005) is a useful method to determine the primary ratio in the tracer method. The purpose of the program is to feasible MRS calculation via a user-friendly GUI. The MRS application is not limited in OC/EC tracer method, but can also be extended to other applications as long as a reliable tracer is available.

MRS calculation can be done by different temporal cycles (batch calculation): by year, by year&season, by season, by year&month, by month, by year&month&hour. Data filter is also available to calculate MRS on a specific subset of data.

For more details regarding the evaluation of the MRS method, please refer to

Wu, C. and Yu, J. Z.: Determination of primary combustion source organic carbon-to-elemental carbon (OC / EC) ratio using ambient OC and EC measurements: secondary OC-EC correlation minimization method, Atmos. Chem. Phys., 16, 5453-5465, doi:10.5194/acp-16-5453-2016, 2016.

Wu, C., Wu, D., and Yu, J. Z.: Quantifying black carbon light absorption enhancement with a novel statistical approach, Atmos. Chem. Phys., 18, 289-309, doi:10.5194/acp-18-289-2018, 2018.

*If you are using this tool in your publication, please cite these papers.

MRS approach adoption in literature:

Wu, C., Wu, D., and Yu, J. Z.: Estimation and Uncertainty Analysis of Secondary Organic Carbon Using One‐Year of Hourly Organic and Elemental Carbon Data. Journal of Geophysical Research: Atmospheres, 124. https://doi.org/10.1029/2018JD029290

Ji, D., Gao, M., Maenhaut, W., He, J., Wu, C., Cheng, L., Gao, W., Sun, Y., Sun, J., Xin, J., Wang, L., and Wang, Y.: The carbonaceous aerosol levels still remain a challenge in the Beijing-Tianjin-Hebei region of China: Insights from continuous high temporal resolution measurements in multiple cities, Environment International, 126, 171-183, doi: https://doi.org/10.1016/j.envint.2019.02.034, 2019.

Ying, Q., Feng, M., Song, D., Wu, L., Hu, J., Zhang, H., Kleeman, M. J., and Li, X.: Improve regional distribution and source apportionment of PM2.5 trace elements in China using inventory-observation constrained emission factors, Sci.Total.Environ., 624, 355-365, doi: https://doi.org/10.1016/j.scitotenv.2017.12.138 2018.

Ji, Y., Qin, X., Wang, B., Xu, J., Shen, J., Chen, J., Huang, K., Deng, C., Yan, R., Xu, K., and Zhang, T.: Counteractive effects of regional transport and emission control on the formation of fine particles: a case study during the Hangzhou G20 summit, Atmos. Chem. Phys., 18, 13581-13600, https://doi.org/10.5194/acp-18-13581-2018, 2018.

Bian, Q., Alharbi, B., Shareef, M. M., Husain, T., Pasha, M. J., Atwood, S. A., and Kreidenweis, S. M.: Sources of PM2.5 carbonaceous aerosol in Riyadh, Saudi Arabia, Atmos. Chem. Phys., 18, 3969-3985, doi: https://doi.org/10.5194/acp-18-3969-2018, 2018.

Xu, J., Wang, Q., Deng, C., McNeill, V. F., Fankhauser, A., Wang, F., Zheng, X., Shen, J., Huang, K., and Zhuang, G.: Insights into the characteristics and sources of primary and secondary organic carbon: High time resolution observation in urban Shanghai, Environ Pollut, https://doi.org/10.1016/j.envpol.2017.10.003, 2017.

"IGOR Pro is a scientific data analysis software, numerical computing environment and programming language that runs on Windows or Mac operating systems. It is developed by WaveMetrics Inc., and was originally aimed at time series analysis, but has since then evolved and covers other applications such as curve fitting and image processing. It comes with a fully functional programming language and compiler, but many functions are also accessible through menus. IGOR Pro is primarily known for its graphics capabilities, and like Origin and other similar programs, is often used to generate plots for scientific and other publications. "

Igor Pro Wikipedia page https://en.wikipedia.org/wiki/IGOR_Pro