Illinois Compiled Statutes Ch. 420, §§ 46/5, 46/26--35
Establishes that, before a lease is signed and upon request during a tenancy, a landlord must provide tenants a state-approved radon pamphlet, any records indicating a radon hazard in the dwelling, and a specified radon warning statement that strongly recommends all rental properties be tested for radon and mitigated if elevated levels are found. Requires the disclosure to be signed by the tenant and landlord as specified in the law. Requires that installation of mitigation systems be carried out by radon contractors. Provides that the tenant may have radon mitigation performed only with the express consent of the lessor, and in such cases may deduct the cost of the installation from the tenant's rent. Establishes the right of tenants to terminate the lease in certain situations if radon testing shows radon levels in excess of the state action level and the radon hazard is not mitigated. Prohibits home rule units from regulating lease agreements or tenant rights in a manner inconsistent with the law.
Illinois Compiled Statutes Ch. 225, § 10/5.8
Requires licensed day care centers, day care homes, and group day care homes to test for radon at least once every three years, in accordance with state rules. Directs Department of Children and Family Services to require proof of radon testing in connection with initial or renewal license applications. Requires providers to post in the facility a copy of the most recent radon measurement report and to provide report to parents and guardians upon request. Also requires report to include a general warning statement about radon in homes. Regulations adopted by the Department (89 Ill. Admin. Code 406.4, 407.370, 408.10) incorporate the radon testing requirements.
Illinois Compiled Statutes Ch. 420, §§ 52/1 et seq.
Requires that all new residential construction include passive radon-resistant construction techniques. Provides that installation of active radon mitigation systems, including installation of a radon vent fan or upgrade of a passive system, must be carried out by radon contractors. Rules adopted by the Illinois Emergency Management Agency (Ill. Admin. Code 422.160) establish construction methods "intended to resist radon entry and prepare the building for post-construction radon mitigation, if necessary."
Illinois Compiled Statutes Ch. 105, § 5/34-205

Requires the local board of education in cities with over 500,000 inhabitants to propose, by January 2012, school facility performance standards that address indoor air quality and other issues. Chicago Public Schools has developed Facility Performance Standards pursuant to the law, which include requirements for use of low-VOC materials, green cleaning products, mechanical ventilation systems, minimum outdoor air supply, and minimum air filtration. (Standards available at: http://www.cps.edu/About_CPS/Policies_and_guidelines/Pages/facilitystandards.aspx.)

Illinois Compiled Statutes Ch. 105, § 5/10-20.48
Recommends that occupied school buildings be tested every five years for radon. Recommends that if radon levels are 4.0 pCi/L or above, the affected areas be mitigated by a licensed radon mitigation professional. Recommends that new schools be built using radon-resistant new construction techniques consistent with EPA guidance. Requires reporting of radon test results to the state Board of Education, which must submit a report every two years to the Governor and Legislature containing the results from all schools that have performed radon tests.
Illinois Compiled Statutes Ch. 20, § 405/405-216
Requires that every state-owned building adopt a green cleaning policy whereby the building purchases and uses only environmentally-sensitive cleaning products, in compliance with the guidelines and specifications established under separate state law (Ill. Comp. Stat. Ch. 105 §§ 140/1 et seq.). Exempts buildings if adherence to the policy would result in an increase in the cleaning costs of the building. (Guidelines adopted at 23 Ill. Admin. Code 2800.10 et seq.)
Illinois Compiled Statutes Ch. 105, §§ 140/1 et seq.
Requires the state to establish and amend annually guidelines for environmentally-sensitive cleaning and maintenance products for schools. Requires all elementary and secondary schools to establish a green cleaning policy and to purchase and use environmentally-sensitive cleaning products pursuant to the guidelines and specifications established under the law. The Illinois Green Governments Coordinating Council has adopted a rule to implement the law (23 Ill. Admin. Code 2800.10 et seq.). Statute amended in 2009 to require that guidelines developed by the state be used for state-owned buildings as well.
Illinois Compiled Statutes Ch. 420, §§ 46/1--25

Establishes requirements for providing information about radon during residential real property sales. Requires sellers to disclose known elevated radon levels in the home and to provide buyers a state-developed pamphlet on radon testing and a general warning statement recommending radon testing prior to all home purchases and mitigation of elevated levels. (State approved forms available at: https://iemaohs.illinois.gov/nrs/radon/realestate.html.) Also requires landlords of residential rental units below the third story to notify current and prospective tenants of any radon hazard revealed by landlord's testing of the property, unless landlord mitigates the property and eliminates the hazard. Requires landlord to disclose to prospective tenants any radon hazard revealed by current tenants' testing, unless landlord's testing demonstrates that a hazard does not exist.

Illinois Compiled Statutes Ch. 410, §§ 105/1 et seq.
Authorizes the state health agency to adopt rules establishing a program for state registration of mold professionals.
Illinois Compiled Statutes Ch. 410, §§ 87/1--15

Requires the Board of Health to ensure the development of criteria for acceptable indoor air quality, a program for the certification of IAQ inspectors, and educational activity on indoor air quality for public and private agencies. Also requires the board to develop statewide IAQ guidelines, including ventilation standards, source control, and occupancy control guidelines. Guidelines adopted pursuant to the law establish non-binding Criteria for Acceptable Indoor Air Quality, including parameters for humidity, temperature, carbon dioxide, carbon monoxide, hydrogen sulfide, ozone, particulates, nitrogen dioxide and formaldehyde. (See "IDPH Guidelines for Indoor Air Quality" at http://www.idph.state.il.us/envhealth/factsheets/indoorairqualityguide_fs.htm.)