Beyond electrostatic precipitators, what techniques can also be used to mitigate harmful or toxic air pollutants?

 
I chose to take a closer look at the Four Corners Generating Station located near Fruitland, New Mexico on the Navajo Nation because it is near where my family lives and coal has been a part of many tribal member’s lives for generation. This coal-fired power plant was originally developed with five coal-fired units but currently only two units are operational. Arizona Public Service Company (APS), the majority owner of the last two units, is planning on decommissioning them within the next 10 years. It generates power using a boiler and steam turbine generator and receives its coal supply from a nearby Navajo coal mine via a connected railroad. The coal is burned which creates high pressure steam that turns the turbine generator and produces electricity. This is then sent through transmission lines owned by APS and distributed to customers both on and off the Navajo Nation.
Emissions from this facility include sulphur dioxide and nitrogen oxide which caused health related issues for neighbors of the plant, even with safety measures like electrostatic precipitators in place. In 2015, after environmental groups filed a complaint citing a violation of the Clean Air Act, a settlement was reached that required a 160 million dollar investment to environmental upgrades for the plant, 6.7 million dollars to go towards health and environmental mitigation projects for tribal members and a civil penalty of 1.5 million dollars. With the planned decommission of this facility in the next decade, there has been a huge uproar for tribal members who have worked in the coal industry for generations and worry about what the future holds for them.  
Kasper, M. (2018, October 1). Replacing coal with more coal: how Arizona Public Service’s Four Corners coal plant hurt customers, but earned investors profits. Enery and Policy Institute.  
https://www.energyandpolicy.org/arizona-public-service-four-corners-power-plant/ (Links to an external site.)
Nguyen, D. (2019, July 9). As Plant Faces Closure, New Mexico City Weights Bet on Clean Coal Technology. Elemental Reports.
https://elementalreports.com/renewable-energy/2019/07/09/as-plant-faces-closure-city-in-four-corners-region-weighs-bet-on-clean-coal-technology/ (Links to an external site.)