08/04/2025
Decades in the Making: EPA Cites Source Control as a Best Practice for IAQ
Posted on 07/29/2025
The U.S. Environmental Protection Agency (EPA) has finally acknowledged what NADCA has championed for decades: source removal is a key strategy for improving indoor air quality. In its newly released IAQ fact sheet, the EPA outlines three core best practices: source control, improved ventilation, and effective filtration and air cleaning.
For NADCA and its certified professionals, this isn’t new guidance; it’s long-overdue recognition of the standards and best practices we’ve built our entire industry around. Now is the moment to amplify that message.
NADCA’s Science is Already Leading the Way
As IAQ takes center stage in conversations about public health and building safety, NADCA is helping move the industry forward with science-based standards and field-tested methods. Our members don’t just follow best practices - they help define them.
This moment is an opportunity to reinforce the role that NADCA professionals play in delivering healthier indoor environments. Here’s how we support each of the EPA’s key strategies:
Source Control - NADCA has long led the charge in advocating for source removal cleaning, the most effective method for eliminating contaminants inside HVAC systems. This approach is central to ACR, the NADCA Standard, which provides detailed protocols for identifying and removing dust, debris, and microbial growth. The EPA highlights source control as the first and most important step in improving IAQ (a practice that NADCA has recognized and implemented industry-wide for more than 35 years).
Improved Ventilation - Clean ductwork enables HVAC systems to operate efficiently, ensuring that fresh air can circulate freely throughout a building. NADCA-certified professionals are trained to evaluate system airflow, identify restrictions, and offer solutions that improve ventilation and air exchange, which are key components of a healthier indoor space.
Filtration and Air Cleaning - When HVAC systems are dirty, even the best filters can’t perform effectively. Cleaning the system helps restore filtration efficiency, reduces the chance of particle bypass, and supports the overall performance of air cleaning systems. NADCA’s training addresses this dynamic directly, equipping professionals with the knowledge to make filtration more effective through system hygiene.
Standards Built on Science and Experience
NADCA’s credibility in this space is rooted in science, continuous education, and real-world application. ACR, the NADCA Standard, is maintained by a committee of subject matter experts and grounded in research, collaboration with affiliated standard-writing organizations, and decades of field experience. NADCA also invests in studies that examine the impact of clean HVAC systems on airflow, energy efficiency, and occupant health.
These efforts help ensure our standards evolve with the science, keeping NADCA members at the forefront of indoor environmental health.
A Shared Mission for Cleaner Air
While the EPA fact sheet brings welcome national attention to IAQ, NADCA’s work has been building toward this moment for years. As industry professionals, we all share the same goal: to create healthier indoor environments where people live, work, and learn.
NADCA is proud to have a voice in this space by advancing standards, educating the public, and empowering our members to deliver on the promise of cleaner air. Together with public health leaders, HVAC professionals, and building managers, we’re making indoor air quality a priority and delivering scientific results that back common-sense practices.
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