EXHIBIT 1

JOINT FILING AGREEMENT

ADVANCED EMISSIONS SOLUTIONS, INC.

In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned hereby confirm the agreement by and among them to the joint filing on behalf of them of the Statement on Schedule 13G and any and all further amendments thereto, with respect to the securities of the above referenced issuer, and that this Agreement be included as an Exhibit to such filing.  This Agreement may be executed in any number of counterparts each of which shall be deemed to be an original and all of which together shall be deemed to constitute one and the same Agreement.

IN WITNESS WHEREOF, the undersigned hereby execute this Agreement as of February 12, 2021.

APOLLO A-N CREDIT FUND (DELAWARE), L.P.
By:	Apollo A-N Credit Advisors (APO FC Delaware), L.P.,
	its general partner
	By:		Apollo A-N Credit Advisors (APO FC-GP), LLC,
			its general partner
			By:		/s/ Joseph D. Glatt
			Name:		Joseph D. Glatt
			Title:		Vice President
APOLLO A-N CREDIT MANAGEMENT, LLC
By:		/s/ Joseph D. Glatt
Name:		Joseph D. Glatt
Title:		Vice President
APOLLO CREDIT STRATEGIES MASTER FUND LTD.
By:	Apollo ST Fund Management LLC,
	its investment manager
	By:			/s/ Joseph D. Glatt
	Name:			Joseph D. Glatt
	Title:			Vice President
APOLLO ST FUND MANAGEMENT LLC
By:		/s/ Joseph D. Glatt
Name:		Joseph D. Glatt
Title:		Vice President

1

APOLLO ST OPERATING LP
By:	Apollo ST Capital LLC,
	its general partner
	By:		/s/ Joseph D. Glatt
	Name:		Joseph D. Glatt
	Title:		Vice President
APOLLO ST CAPITAL LLC
By:		/s/ Joseph D. Glatt
Name:		Joseph D. Glatt
Title:		Vice President
ST MANAGEMENT HOLDINGS, LLC
By:		/s/ Joseph D. Glatt
Name:		Joseph D. Glatt
Title:		Vice President
APOLLO CREDIT MANAGEMENT, LLC
By:		Apollo Capital Credit Management, LLC,
		its sole member
		By:		/s/ Joseph D. Glatt
		Name:		Joseph D. Glatt
		Title:		Vice President
APOLLO CAPITAL CREDIT MANAGEMENT, LLC
By:		/s/ Joseph D. Glatt
Name:		Joseph D. Glatt
Title:		Vice President

2

APOLLO SA MANAGEMENT, LLC
By:	Apollo Capital Management, L.P.,
	its sole member
	By:		Apollo Capital Management GP, LLC,
			its general partner
			By:			/s/ Joseph D. Glatt
			Name:			Joseph D. Glatt
			Title:			Vice President
APOLLO CAPITAL MANAGEMENT, L.P.
By:	Apollo Capital Management GP, LLC,
	its general partner
	By:			/s/ Joseph D. Glatt
	Name:			Joseph D. Glatt
	Title:			Vice President
APOLLO CAPITAL MANAGEMENT GP, LLC
By:		/s/ Joseph D. Glatt
Name:		Joseph D. Glatt
Title:		Vice President
APOLLO MANAGEMENT HOLDINGS, L.P.
By:	Apollo Management Holdings GP, LLC,
	its general partner
	By:				/s/ Joseph D. Glatt
	Name:				Joseph D. Glatt
	Title:				Vice President
APOLLO MANAGEMENT HOLDINGS GP, LLC
By:		/s/ Joseph D. Glatt
Name:		Joseph D. Glatt
Title:		Vice President

3