Reproduce example iF for Richmond facility

# Summary

* On p. 20 of [Apte et al (2019)][apte2019method], example iFs for a hypothetical facility in Richmond CA are given.
* The objective of this issue is to reproduce intermediate calculations in a language-agnostic way (with example code as needed), with special attention to `PrimaryPM25`.
* The aim is to assist in resolving issue #1.

# Details

## Basis

* ISRM cell ID appears to be `#1481`(screenshot below, or inspect [ISRM_US_SFAB_cell_geometries])
- [ ] Prerequisite: resolve #5
- [ ] UW to confirm this is that cell ID **within that ISRM** (in case cell numbering differs by ISRM)

- [ ] `PrimaryPM25` value in S-R matrix for this source cell, and this cell as a receptor too (i.e, self-contribution), is _____ ppm.
- [ ] Ground-level iF for `PrimaryPM25` for this cell, across all SFAB cells, is ________ ppm. This is [within 10%? y/n] of the value across all CA cells, which is 6.2 ppm.

# Expectation

* Expecting an iF of **6.2 ppm** for `PrimaryPM25` for cell `#1481`:

[apte2019method]: ../blob/master/References/Literature/PDF/apte2019method.pdf

[Zenodo]: https://zenodo.org/record/2589760#.YgREvS2ZPEa

[ca_isrm.ncf]: https://drive.google.com/drive/folders/1WmLRz7iWo2MjtSikgHEig7M0NvK2sOns?usp=sharing

[ca_isrm_gridcells.csv]: ../blob/40da61d/Data/UW/2022-02-10/ca_isrm_gridcells.csv

[CMAQ boundary]: ../blob/40da61d/Build/RData/

[ISRM_US_SFAB_cell_geometries]: https://github.com/BAAQMD/InMAP-SFAB/blob/master/Build/Geodata/ISRM_US_SFAB_cell_geometries.geojson

Read References/Literature/PDF/apte2019method.pdf and inspect Build/Geodata/ISRM_US_SFAB_cell_geometries.geojson plus Data/UW/2022-02-10/ca_isrm_gridcells.csv. Resolve the cell-ID prerequisite and reproduce the PrimaryPM25 S-R self-contribution and ground-level iF calculations. Done means checking whether the SFAB result is within 10% of the cited 6.2 ppm California value.

Written by the indexing model from the issue text.