States Are Innovating to Improve Indoor Air Quality
February 07, 2025 | Abe Kulungara
Whether at home, in the workplace, or in schools, the air we breathe inside is affected by improper ventilation, exposure to toxic chemical cleaning agents, buildup of moisture, and the presence of pests—all of which contribute to poor indoor air quality (IAQ). In addition, increases in extreme weather conditions (e.g., heat, hurricanes, flooding) can deteriorate buildings, reducing the physical barriers between outdoor and indoor spaces. And inadequate weatherization of schools and buildings can lead to indoor fungi and mold growth.
Indoor air pollutants can have both short-term and long-term impacts on public health and well-being. Some examples of health outcomes (and their associated hazards) include: acute injury (carbon monoxide and other asphyxiants from combustion and safety hazards from improper design), cancer (asbestos and radon), infectious disease (COVID-19), as well as allergic disorders and asthma (mold and other products of damp indoor environments. Furthermore, poor IAQ in school can potentially affect comfort, concentration, and student performance.
While the United States has made significant progress in improving outdoor environmental quality, improvements in indoor environments have been much slower, despite Americans spending approximately 90% of their lives indoors. In many cases, the responsibility for improving IAQ falls to individual states, resulting in a patchwork of regulations and varied approaches across the country.
Indoor Air Quality at the Federal Level
The federal government’s authority over indoor air quality is limited to federal buildings but there is no current comprehensive national regulation specifically focused on indoor air quality. Notwithstanding, federal laws and regulations addressing outdoor air quality can indirectly impact indoor air quality. For example, the Clean Air Act gives EPA the authority to establish and enforce National Ambient Air Quality Standards (NAAQS) for pollutants in outdoor air, such as ground-level ozone, particulate matter, and carbon monoxide. Improvements to ambient air quality will have an impact on indoor air quality as well.
Even though the federal government’s role in IAQ is less direct, agencies including EPA have issued voluntary guidelines and best practices. This gap in federal regulations offers state and local governments the opportunity to set standards for their jurisdictions.
The Model Clean Indoor Air Quality Act
The Model Clean Indoor Air Quality Act (MCIAA) provides a framework for states to adopt and implement measures that are most relevant to their local needs and circumstances, much like the Model Food Code is used by states for food safety regulations.
The Act consists of six main articles, each containing key sections designed to support a comprehensive mission of safeguarding and enhancing IAQ in public buildings through collaboration among public and private entities. The Act also presents extensive statutory language on IAQ and offers states the flexibility to choose the components that best suit their specific needs, priorities, and local conditions. By adopting the Model Act or portions of it, states can establish standards for ventilation, moisture control, hazardous materials use, and public education efforts.
State Actions on Indoor Air Quality
A growing number of states are proactively improving indoor air quality. Massachusetts recently introduced SD 2588, which incorporates language from MCIAA, while others are addressing IAQ issues more broadly, enacting legislation that prohibits smoking in indoor public spaces or responding to specific local challenges (e.g., mold, radon, volatile organic compounds ). At least five states are considering various bills relating to air quality in public schools. Massachusetts (SD 173 and SD 630) and New Jersey (S 1033) are establishing task forces or commissions to study indoor air quality. Connecticut (HB 5873), New York (A 2649) Virginia (HB 2618 and SB 1413) are establishing or amending indoor air quality standards for public schools. Massachusetts (HD 2890) is also prohibiting cleaning agents that could have an adverse effect on health.
As states consider streamlining indoor air quality standards using the MCIAA, there are a large number of current statutes that improve IAQ. For example, Florida requires their Department of Health to have an IAQ testing and monitoring program to assess health risks from exposure to chemical, physical, and biological agents in the indoor environment. In Hawaii, the Department of Health is authorized to correct indoor air pollution problems in all buildings. The agency must establish and coordinate an IAQ assessment network involving state agencies and managers of publicly owned buildings to identify, evaluate, and resolve indoor air pollution problems. The statute also grants the agency the authority to implement a program for approving plans to construct, inspect, and monitor ventilation systems, as well as to provide IAQ information to managers, owners, and occupants of both public and private buildings. Other states, such as Washington and Oregon, have implemented programs that focus on IAQ in schools, acknowledging children’s unique vulnerabilities to poor air quality.
ASTHO will continue to monitor and provide updates.