Indoor Air Quality Standards – Why, When, How, and Where

Indoor air quality is incredibly important. It affects our short-term and long-term health and plays a major role in our mood, energy, and productivity throughout the day. However, it’s not enough to simply say that the air quality is good or bad. We need something to give us a more precise understanding of the air we breathe.

Air quality standards exist to let us know whether the air we’re breathing is good or bad and in which specific ways. Combined with accurate measuring and monitoring solutions, indoor air quality standards can let us know if the air is clean in any area at any given time. We can know whether or not there are dangerous levels of various contaminants so that we can keep everyone safe.

Indoor air quality standards vary around the world and have evolved over time. Here’s a closer look at the history of air quality and where it stands today.

The History of Indoor Air Quality

The world has grown in leaps and bounds over the past decades in our understanding of indoor air quality, its effects, and its importance. While many of the most important developments have come somewhat recently, the history between people and the air we breathe is long and complex.

Throughout much of human history, indoor air quality wasn’t recognized as an area of significant concern. In largely agrarian societies, the air inside was much the same as it was outside. Ventilation wasn’t a major issue when most homes and buildings didn’t have closing doors or windows. The air was fresh and clean just about everywhere.

When the industrial revolution began in the 1700s and coal began to be used at an accelerating rate, people began to take notice of air quality. The consequences of widespread coal use in urban areas were severe, with soot and smoke leading to smog and other negative air quality consequences. As other fuel sources were discovered, the direct impact of coal began to wane, but cities still faced major issues.

Technology continued to develop, and new processes brought new types of contamination. During the 1900s, smog was becoming a massive problem. In many countries, people began to take action. Among the most notable such actions were the 1970 Clean Air Act Amendments in the US, which established air pollution standards.

Since then, the air in American cities and many others around the world has drastically improved. While some cities still suffer from severe smog, this is primarily in countries that haven’t adopted the same level of air pollution standards. While outdoor air was steadily improving, there was still indoor air quality to consider.

While many countries began to adopt indoor air quality standards in the 1970s and onward, many of these standards were ineffective. They took to simple a view of indoor air quality, simply mandating bulk ventilation requirements. In many cases, standards were counterproductive due to an emphasis on air recycling and building sealing meant to conserve energy.

Today, most indoor air quality standards have been greatly improved. While there is still a need to implement the latest technologies and methods that are now possible, these indoor air quality standards are helping people breathe easier all around the world.

ASHRAE Air Quality and Ventilation Standards

The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) is an important professional association that develops safety and environmental standards in the United States. This major organization also provides technical standards around the world, setting a baseline for HVAC and air quality.

Standard 62 was first published in 1973 and featured a variety of technical requirements for ventilation. The standard has been updated and improved by ASHRAE over the decades since, and the current standard today is Standard 62.1-2019.

This document focuses primarily on ventilation design as the primary means of ensuring indoor air quality. Rather than a dynamic approach, the standard seeks to ensure that all new buildings have the required ventilation to ensure air quality at the time of their construction.

Within the standard, there are technical requirements for indoor air quality, ventilation rates, and natural ventilation. They set a baseline for minimum ventilation requirements for buildings that can be used to plan new construction and updates.

An additional standard from ASHRAE focuses on indoor air quality in residential buildings, Standard 62.2-2019. This standard has different requirements based on the compartmentalization of living units in multifamily dwellings. It includes a wide range of insights not how building owners can improve indoor air quality to meet compliance, including filtration, ventilation system design, and more.

ASHRAE Standard 62.1-2019 isn’t a legal requirement in itself. It is a voluntary standard that is adopted in countries throughout the world. However, many state and local building codes cite the standard as a requirement, making it mandatory in those locations.

The EPA and Indoor Air Quality

The Environmental Protection Agency (EPA) is an agency of the US federal government that handles a wide range of environmental matters. It was first established in 1970, creating an independent agency that took over and expanded the responsibilities of the U.S. Public Health Service’s Environmental Health Divisions.

The EPA provides an extensive range of indoor air quality guidance for individuals and organizations. This includes a wide range of guides on indoor air quality testing and management, along with specific guides for threats like asbestos and radon. The EPA provides thresholds for specific contaminants that can impact indoor air quality.

One of the most important categories of contaminants is small particulate matter. This can include dust, mold, pollen, and a wide range of other potentially harmful compounds. Particles are separated into categories based on their diameter, with the 2.5-micrometer range being particularly hazardous. This category is referred to as PM2.5.

 

The EPA recommends that indoor air quality be maintained with PM2.5 levels below 25 micrograms per cubic meter, averaged over a 24-hour period. Beyond that level, individuals can experience short-term symptoms and potential long-term health risks.

Carbon dioxide is another important compound for indoor air quality. It’s the naturally occurring gas that people breathe out and a product of combustion. It’s only a major risk when concentrations reach over ten times the standard outdoor level, which can happen in a confined space with many people and no ventilation for a long period.

The EPA also sets standards for less common and more dangerous contaminants. Carbon monoxide is a partial combustion byproduct that can be released by faulty furnaces and water heaters. Its colorless, odorless, and extremely poisonous. As such, it poses an immediate threat to anyone present.

The threshold for carbon monoxide is set at nine parts per million (ppm) averaged over an eight-hour period. Anything above this is considered dangerous and to be avoided, which is why carbon monoxide detectors are so important in homes that use natural gas or other combustible fuel sources.

Radon is another potential threat to homes and buildings. This radioactive gas seeps into homes from underground and causes an increased risk of cancer. The EPA recommends corrective action be taken for any building with a level above four pCi/L.

The EPA doesn’t enforce these standards. It only sets health and safety guidelines that let individuals and organizations know when action should be taken to remedy indoor air quality issues.

OSHA Air Contaminant Safety Thresholds

The Occupational Safety and Health Administration (OSHA) is a major US regulatory agency that takes action to assure safe and healthy working conditions. Their inspections and enforcements are an effective tool in ensuring workplace safety.

The agency has the power to issue citations and fines to employers that violate OSHA standards. While OSHA doesn’t have comprehensive indoor air quality requirements, regulations include a general duty clause that enables OSHA to enforce air quality standards established by other agencies.

Among the most important are the recommended exposure limits established by the National Institute for Occupational Safety and Health (NIOSH). These limits set thresholds for an extensive range of contaminants, including inhalation, ingestion, and physical contact exposure.

Additional thresholds can come from the American Conference of Governmental Industrial Hygienists (ACGIH) and the American Industrial Hygiene Association (AIHA). OSHA is effective in ensuring that indoor air quality incidents that lead to injury or illness are identified and addressed, but the complexity of its framework makes them an ineffective resource for indoor air quality planning and management.

European Union Indoor Air Quality Standards

While many countries use examples from ASHRAE and the EPA as a foundation for their own indoor air quality standards, the European Union has developed standards through the Ambient Air Quality Directives, overseen by the European Environment Agency. These directives set standards for a variety of specific air pollutants.

European air quality standards put in place a series of progressive thresholds for average annual PM2.5 concentrations. This began at 25 µg/m³ and, as of 2020, has been reduced to 20 µg/m³. They also provide a threshold for larger airborne particles, PM10, at 50 µg/m³.

The standard implements a 10 mg/m³ 8-hour average threshold for hazardous carbon monoxide. Other important pollutants given thresholds include sulfur dioxide, nitrogen dioxide, lead, benzene, arsenic, cadmium, and ozone.

Under the guidance of the European Green Deal agreement, the European Union is currently in the process of revising its air quality standards to bring them in line with recommendations from the World Health Organization.

World Health Organization Air Quality Guidelines

The World Health Organization (WHO) is an agency of the United Nations that strives to ensure health around the world. It is based in Geneva, Switzerland, with over 150 offices around the world. The organization plays an important role in many global health initiatives, particularly in the prevention and treatment of infectious diseases.

 

Due to the significant impact of indoor air quality on health around the world, the WHO has published a wide range of indoor air quality guidelines, including thresholds for exposure to pollutants. These guidelines are an important resource for public health professionals around the world and serve to help them better protect the public from adverse health effects.

The WHO guidelines focus on a variety of harmful air contaminants that can cause both short-term and long-term health consequences. Their carbon monoxide guidelines cover thresholds for different exposure periods, including 100 mg/m³ for 15 minutes, 35 mg/m³ for 1 hour, and 10 mg/m³ for 8 hours.

These guidelines give 1 μg/m³ as the concentration of benzene that creates an excess lifetime risk for cancer, although they do not provide any safe threshold level. Formaldehyde, naphthalene, radon, nitrogen dioxide, polycyclic aromatic hydrocarbons, and trichloroethylene are all given specific thresholds over certain periods of time.

The WHO provides United Nations member states with assistance in implementing these guidelines to ensure the health of their citizens. Attaining these indoor air quality standards can greatly improve health, but they can be difficult to implement for individual buildings and organizations.

Finding the Right Tools to Implement Indoor Air Quality Standards

Many of the world’s indoor air quality standards have similar specific requirements for airborne contaminant concentrations. The real challenge is ensuring that indoor air actually meets those requirements. While organizations can choose to follow construction and ventilation guidelines that promise to deliver sufficient air quality, how can they really be sure?

The simple fact of the matter is that any comprehensive approach to indoor air quality requires active measurement. Relying on design specifications or even occasional professional services to determine the quality of air in indoor environments isn’t enough. To know that indoor air is safe and clean, we need to measure it.

People need to know that their indoor environments have clean air, and they need to know what actions they can take to improve and manage air quality. Sol-In provides a robust indoor air quality monitoring and management solution that lets them do just that. If you’d like to know more about how you can realize indoor air quality standards in your building, you can contact Sol-In today.