Designing Healthier Homes by Eliminating Fossil Gas Appliance Emissions
By Positive Energy staff
The Architect's Role in Indoor Environmental Quality
Architects, as the primary designers of our built environment, hold a profoundly influential position in shaping the health and well-being of building occupants. Beyond the critical considerations of aesthetics, structural integrity, and energy performance, a deep understanding of the invisible forces at play within a building's envelope is increasingly paramount. This report aims to equip architects with the essential knowledge to proactively design for superior indoor air quality (IAQ), particularly concerning emissions from common household gas appliances. The decisions made during the design phase, from material selection to mechanical system integration, directly influence the indoor environment and, by extension, the health outcomes of those who inhabit these spaces. This effectively positions architects as critical guardians of public well-being within the built space, expanding their traditional role to encompass a vital public health responsibility.
Unmasking the Impact of Gas Appliances on Home Health
While gas appliances, such as stoves and heaters, are ubiquitous in modern homes due to their convenience and efficiency, their combustion byproducts and even unburned gas can significantly degrade indoor air quality. This degradation poses documented health risks that have been the subject of extensive scientific inquiry over the past two decades.1 These appliances release a complex cocktail of pollutants that, when confined within residential structures, can lead to a range of adverse health effects. The presence of these combustion products and hazardous air pollutants (HAPs) in indoor environments warrants a re-evaluation of their widespread use and the design strategies employed to mitigate their impact.2
Bridging Science and Design for Healthier Buildings
This post synthesizes complex scientific findings from leading institutions, including the Rocky Mountain Institute (RMI) 1, the U.S. Environmental Protection Agency (EPA) 3, ASHRAE 2, and Lawrence Berkeley National Laboratory (LBNL).14 The goal is to translate these technical insights into actionable strategies for architectural practice. The report will detail specific pollutants emitted by gas appliances, their associated health effects, and, crucially, how thoughtful design and engineering solutions can effectively mitigate these risks, fostering truly healthier indoor environments.
Fundamentals of Indoor Air Quality (IAQ) for Architects
Defining Good IAQ: Source Control, Ventilation, and Filtration
Good indoor air quality management is fundamentally built upon three interconnected principles: controlling airborne pollutants at their source, ensuring adequate ventilation through the introduction of outdoor air and removal of indoor air, and employing effective filtration to remove contaminants from the air.9 Beyond these, maintaining acceptable temperature and relative humidity levels is also critical for overall IAQ and occupant comfort.10 These principles are not isolated but rather form a synergistic approach to managing indoor air. For example, while ventilation dilutes pollutants, it can also introduce outdoor contaminants, highlighting the need for a comprehensive strategy.22 It is particularly important to control pollutant sources, as IAQ problems can persist even with a properly operating HVAC system if the sources themselves are not addressed.10 This interconnectedness means architects must consider these elements holistically, recognizing that optimizing one pillar without considering the others can lead to suboptimal or even detrimental IAQ outcomes.
The Building as a Dynamic System: How Structure, Systems, and Occupants Shape IAQ
A building's indoor environment is not a static entity but a complex, dynamic system. Its IAQ is profoundly influenced by the intricate interactions among various factors, including the building's geographic site, local climate, physical structure, mechanical systems (HVAC), construction techniques, the array of internal and external contaminant sources, and the activities and behaviors of its occupants.10 Pollutants can originate from within the building itself, such as combustion byproducts from appliances or off-gassing from materials, or they can be drawn in from the outdoors, including vehicle emissions or pollen.10
Air exchange, a critical process for maintaining healthy IAQ, occurs through multiple pathways. These include designed mechanical ventilation systems utilizing fans, uncontrolled infiltration (the leakage of air through cracks and myriad openings in the building envelope), and the intentional opening of windows and doors.11 Air pressure differences, both within and around the building, act as driving forces that can move airborne pollutants through any available openings in walls, ceilings, floors, doors, windows, and even HVAC systems.10 This perspective underscores the importance of viewing the building envelope not as a passive barrier, but as an active, permeable interface that constantly mediates the exchange of air and pollutants between the interior and exterior. This dynamic interplay necessitates a design approach that manages these exchanges intentionally to promote health.
The "Building Tight, Ventilate Right" Imperative and Its IAQ Implications
Modern energy-efficient construction frequently adopts the strategy of "Building Tight, Ventilate Right".21 This approach is primarily driven by the goal of reducing energy consumption by minimizing uncontrolled air leakage, or infiltration, through the building envelope.20 By creating a tighter building, less energy is required for heating and cooling, which is a significant step towards sustainable design.
However, a crucial implication of this strategy is that reduced infiltration and ventilation rates in tightly sealed buildings can lead to a significant increase in the concentration of indoor-generated contaminants.10 The very measures taken to enhance energy efficiency, such as improved insulation and sealing, can inadvertently trap pollutants indoors if not accompanied by compensatory measures. This creates a fundamental tension for architects: while energy efficiency is a vital design objective, it must be meticulously balanced with robust, intentional mechanical ventilation strategies. Without such integrated planning, the unintended consequence can be elevated pollutant levels and compromised indoor air quality, undermining the overall health performance of the building.10 This highlights the necessity of designing for controlled air exchange rather than relying on uncontrolled leakage.
Why Indoor Air Pollutants Often Exceed Outdoor Levels
It is a common, yet often mistaken, assumption that indoor air is inherently cleaner than outdoor air. However, studies conducted by the EPA and other research institutions consistently demonstrate that indoor levels of many air pollutants can be 2 to 5 times, and occasionally more than 100 times, higher than outdoor levels.6 This phenomenon is particularly concerning given that people spend approximately 90% of their time indoors.9
The primary reason for this disparity is the presence of numerous pollutant sources located within the building itself.11 These internal sources include combustion from appliances, off-gassing from building materials and furnishings, and emissions from cleaning products, among many others.6 When these internally generated pollutants are released into a relatively confined space and then trapped by a tighter building envelope—a characteristic of modern, energy-efficient construction—their concentrations can rapidly accumulate and surpass outdoor levels.6 This situation, sometimes referred to as the "concentration trap," means that the primary challenge for architects is not merely preventing outdoor pollutants from entering, but effectively managing and removing the contaminants generated within the home. This understanding underscores the critical need for proactive IAQ design that addresses internal pollutant generation.
Key Pollutants from Gas Appliances and Their Health Implications
Gas appliances, particularly those used for cooking and heating, are significant indoor sources of a variety of pollutants. The combustion process, and even the unburned fuel itself, can release substances that pose substantial risks to human health. Understanding these specific pollutants and their impacts is crucial for architects aiming to design healthier homes.
Nitrogen Dioxide (NO2): A Respiratory Concern
Nitrogen dioxide (NO2) and nitric oxide (NO) are toxic gases, with NO2 being particularly hazardous as a highly reactive oxidant and corrosive agent.3 The primary indoor sources of NO2 are combustion processes, especially from unvented gas stoves, kerosene heaters, and defective vented appliances.2 While electric coil burners also emit NO2, their emission rates are significantly lower than those from gas burners, making gas combustion the predominant concern for this pollutant in residential settings.18
The health effects of NO2 exposure range from immediate irritation to more severe, long-term respiratory conditions. NO2 acts mainly as an irritant, affecting the mucous membranes of the eyes, nose, throat, and respiratory tract.3 Even low-level exposure can significantly impact sensitive individuals, leading to increased bronchial reactivity in asthmatics, decreased lung function in patients with chronic obstructive pulmonary disease (COPD), and a heightened risk of respiratory infections, particularly in young children.3 Extremely high-dose exposure, such as might occur in a building fire, can result in severe outcomes like pulmonary edema and diffuse lung injury.3 Continued exposure to elevated NO2 levels can also contribute to the development of acute or chronic bronchitis.3 ASHRAE identifies NO2 as a potential cause of respiratory disease, underscoring its importance in IAQ considerations.2
Indoor NO2 levels in homes with gas stoves frequently surpass outdoor concentrations.3 Studies by LBNL have consistently shown that NO2 levels in indoor environments where gas appliances are used often approach or exceed ambient air quality standards.14 For example, in an experimental kitchen, NO2 concentrations reached as high as 2500 µg/m3 when there was no stove vent and low air exchange.14 Further research in energy-efficient homes revealed that NO2 levels in both kitchens and living rooms frequently exceeded the EPA's proposed one-hour ambient air quality standard of 470 µg/m3 (equivalent to 100 ppb) following typical gas stove use.14 A study of nine Northern California homes found that four of them had kitchen 1-hour NO2 concentrations exceeding the national ambient air quality standard (100 ppb), with elevated levels also observed throughout the home, including bedrooms.17 This demonstrates that homes with gas stoves are actively creating an indoor environment that disproportionately impacts sensitive individuals, particularly children, placing them at higher risk for respiratory illness and infection.
Carbon Monoxide (CO): The Silent, Deadly Gas
Carbon monoxide (CO) is a particularly insidious pollutant because it is an odorless, colorless, and toxic gas, making it impossible to detect without specialized alarms.4 It is a primary product of the incomplete combustion of natural gas.2 Key indoor sources from gas appliances include unvented gas space heaters, gas stoves, and back-drafting from other combustion appliances such as furnaces, gas water heaters, wood stoves, and fireplaces.3 The risk of CO emissions significantly increases with poorly adjusted or inadequately maintained combustion devices.4
The health effects of CO exposure vary widely based on the concentration, duration of exposure, and the individual's age and overall health.4 Acute effects are primarily due to the formation of carboxyhemoglobin in the blood, which severely inhibits the body's ability to absorb and transport oxygen.4 At low concentrations, CO can cause fatigue in healthy individuals and chest pain in those with pre-existing heart disease. Moderate concentrations may lead to symptoms such as angina, impaired vision, and reduced brain function. At higher concentrations, individuals may experience impaired vision and coordination, headaches, dizziness, confusion, nausea, and flu-like symptoms that typically resolve upon leaving the affected area. At very high concentrations, CO exposure is fatal.4 Given these severe risks, ASHRAE strongly recommends the installation of carbon monoxide alarms in all homes, regardless of the heating fuel type used.2
Typical CO levels in homes without combustion appliances generally range from 0.5 to 5 parts per million (ppm). In homes with properly adjusted gas stoves, levels are often between 5 and 15 ppm, but near poorly adjusted stoves, these levels can escalate to 30 ppm or higher.4 While an LBNL study in an energy-efficient house did not find CO levels exceeding the EPA one-hour standard (40 mg/m3) 14, it is important to acknowledge that the U.S. Consumer Product Safety Commission (CPSC) reports approximately 170 deaths annually from CO produced by non-automotive consumer products, including malfunctioning fuel-burning appliances.2 A critical architectural and engineering concern arises from the interaction of ventilation systems with the building envelope. High airflow range hoods, intended to improve IAQ, can inadvertently create negative pressure within a home, potentially causing other combustion appliances (like furnaces or water heaters) to backdraft, drawing harmful carbon monoxide into living areas.8 This highlights the complex, interconnected nature of building physics, where ventilation design must be carefully integrated with the overall airtightness of the building and the presence of other combustion appliances.
Particulate Matter (PM2.5 & Ultrafine Particles): Microscopic Threats
Particulate matter (PM) found indoors originates from both outdoor air and a variety of indoor activities.8 Key indoor sources include cooking, certain cleaning activities, and combustion processes such as burning candles, using fireplaces, unvented space heaters, kerosene heaters, and tobacco products.8 Gas appliances, particularly unvented ones, are significant sources of ultrafine particles (less than 100 nm in diameter) and respirable particulate matter (PM10 and PM2.5).2 Cooking activities, especially frying, broiling, and grilling, are major contributors to indoor PM2.5 emissions, with the rapid production of large quantities of PM when food is burned.8
The health effects of exposure to airborne particles, particularly fine particles (PM2.5) and ultrafine particles, have been recognized for millennia.13 PM2.5 is especially concerning because its minute size allows it to penetrate deeply into the respiratory system, leading to increased short- and long-term adverse health effects.13 Ultrafine particles have been specifically linked to oxidative damage to DNA and increased mortality.2 The aggregate harm to the population in the indoor environment, measured in Disability Adjusted Life Years (DALY), is overwhelmingly dominated by exposure to particulate matter, surpassing other contaminants by a factor of five.13 This makes PM the single most significant indoor air quality health burden. Furthermore, airborne pathogens, including SARS-CoV-2, are transmitted via respiratory aerosols that are predominantly fine particles.13
Despite the migration of outdoor pollution indoors, particles generated from indoor sources often constitute the majority of an individual's personal exposure.13 LBNL studies confirmed this, showing that natural gas cooking burner use led to very high 1-hour kitchen particle number (PN) concentrations (exceeding 2x10^5 cm-3-h) in all homes studied.17 While ventilation is important for overall IAQ, LBNL research explicitly states that PM2.5-related health burdens are not very sensitive to changes in ventilation rates, and that filtration is significantly more effective at controlling PM2.5 concentrations and their associated health effects.15 This finding is crucial for architects, as it highlights that while ventilation plays a role, filtration is the superior and necessary strategy for mitigating the predominant indoor health risk posed by particulate matter.
Volatile Organic Compounds (VOCs): Formaldehyde, Benzene, and Beyond
Volatile Organic Compounds (VOCs) are emitted as gases from a vast array of indoor products and materials, with their concentrations consistently found to be higher indoors—often 2 to 10 times higher—than outdoors.6 Gas appliances are identified as sources of formaldehyde.14 Beyond combustion, unburned natural gas itself contains hazardous air pollutants (HAPs), notably benzene, which is detected in a high percentage (99%) of residential natural gas samples.23 Benzene is also a known byproduct of combustion processes 2, and other common indoor sources include environmental tobacco smoke and automobile exhaust from attached garages.6
Exposure to VOCs can induce a range of immediate symptoms, including irritation of the eyes, nose, and throat, headaches, dizziness, loss of coordination, and nausea.5 More severe or long-term exposure can lead to damage to the liver, kidneys, and central nervous system.5 Critically, some organic chemicals are known to cause cancer in animals, and several are suspected or confirmed human carcinogens.5 Formaldehyde is particularly well-documented as a cause of sensory irritation and is identified as the primary risk driver for cancer health effects in studies of offices and schools.15 Benzene is unequivocally classified by the EPA as a Group A, known human carcinogen for all routes of exposure, with occupational exposure linked to an increased incidence of leukemia.7
A significant and often overlooked finding is that benzene is detected in 99% of unburned natural gas samples from residential stoves.23 Furthermore, leakage from gas stoves and ovens while they are not in use (i.e., when they are off) can result in indoor benzene concentrations that exceed health reference levels established by the California Office of Environmental Health Hazard Assessment (OEHHA). These concentrations can be comparable to those found in environmental tobacco smoke.23 Such exceedances are particularly likely when there are elevated leakage rates combined with low ventilation rates.23 This finding is particularly important because it means the carcinogenic risk from benzene is not limited to cooking times but is continuous, even when appliances are idle. This significantly strengthens the argument for addressing the source of the fuel itself, as ventilation alone is not highly effective in reducing airborne concentrations of semivolatile organic compounds (SVOCs), which are higher molecular weight VOCs that tend to reside mostly on indoor surfaces.16 This has broad implications for architectural specifications and policy regarding gas appliances.
The Unseen Byproduct with Health and Durability Consequences
Water vapor is a primary product of natural gas combustion.2 Unvented combustion appliances can produce a substantial amount of moisture, contributing significantly to the overall internal moisture load of a home.2 Other internal moisture sources include human respiration and perspiration, cooking, bathing, washing, plants, and pets.24
The presence of dampness in buildings, even in the absence of visible mold growth, has been consistently linked to adverse health outcomes, particularly respiratory problems.2 Mold growth, a common biological contaminant, thrives in high humidity environments, specifically when relative humidity is consistently above 50%.10 Mold is a known trigger for asthma symptoms and allergic reactions.10 A critical interplay exists between energy-efficient design and moisture management. Modern, tightly sealed building envelopes, while beneficial for energy efficiency by reducing sensible cooling loads, can inadvertently reduce the incidental dehumidification provided by cooling systems.24 This means that the moisture generated indoors by gas appliances and other activities is more likely to be trapped, leading to elevated indoor humidity levels if not properly managed. Elevated humidity, in turn, is a primary catalyst for mold growth, creating a feedback loop where energy-efficient design, if not coupled with deliberate moisture control and ventilation strategies, can inadvertently create conditions conducive to mold and associated health problems. This highlights the necessity of integrated design thinking that accounts for moisture balance.
Architectural Strategies for Mitigating Gas Appliance Health Risks
Prioritizing Source Control in Design
Effective indoor air quality management begins with source control—the elimination or reduction of pollutant emissions at their origin. This is often the most impactful strategy for safeguarding occupant health.
Appliance Selection: Embracing All-Electric and Electronic Ignitions
Source control is identified as the primary and most effective method for limiting indoor exposure to volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs).16 ASHRAE explicitly advises consumers who wish to reduce the risk of adverse health effects from combustion products to avoid using unvented appliances.2 When specifying gas cooking appliances, selecting models with electronic ignitions is recommended where possible.2 A profound understanding of the risks associated with gas appliances extends beyond their operational use. The discovery that unburned natural gas leaks from stoves, even when they are off, can continuously release carcinogenic benzene 23, provides a compelling health-based rationale for architects to advocate for and design all-electric homes. This moves beyond solely energy efficiency arguments to directly address a pervasive, continuous, and carcinogenic exposure that cannot be fully mitigated by ventilation alone, offering a significant health benefit to occupants.
Proper Appliance Installation and Maintenance Considerations
For any permanently mounted unvented combustion appliances, strict adherence to manufacturer installation instructions and local codes is paramount, with installation performed by a qualified professional.2 Regular, annual inspections by a qualified service technician are also strongly recommended to ensure proper function and minimize emissions.2 For example, poorly adjusted gas stoves can lead to significantly elevated carbon monoxide levels, potentially reaching 30 ppm or higher.4 The proper installation and ongoing maintenance are critical to preventing dangerous pollutant accumulation in the home.
Designing for Effective Ventilation
Ventilation is a cornerstone of good indoor air quality, essential for diluting and removing pollutants that cannot be entirely eliminated through source control.
The Critical Role of Ducted Range Hoods: Capture Efficiency and Airflow Requirements
Venting nitrogen dioxide (NO2) sources to the outdoors and installing a ducted exhaust fan over gas stoves are among the most effective measures to reduce exposure to combustion pollutants.3 Studies by LBNL demonstrate that operating a venting range hood can substantially reduce cooking burner pollutant concentrations, achieving reductions in the range of 80-95% for well-designed hoods.17 LBNL simulations specifically recommend a minimum capture efficiency of at least 70% for range hoods to avoid unacceptably high 1-hour average NO2 concentrations (100 ppb or higher) and at least 60% capture efficiency to avoid unacceptably high 24-hour average PM2.5 concentrations (25 µg/m3 or higher).18 These targets are particularly crucial for multi-family homes, which have smaller air volumes for pollutant dilution, leading to higher concentrations if not properly managed.18 Range hoods should be operated during cooking and for an additional 10-20 minutes afterward to ensure effective pollutant removal.8 In contrast, recirculating (non-venting) range hoods are largely ineffective for NO2 and CO2, offering only small net reductions, though they may achieve modest PM reductions (~30%).17 This highlights that architects must look beyond raw airflow numbers (CFM) and prioritize the design, geometry, and placement of the hood relative to the cooking surface and the overall kitchen layout to ensure effective pollutant capture, rather than just air movement.
Beyond the Kitchen: Whole-House Ventilation Strategies for Tighter Envelopes
While kitchen-specific ventilation is crucial, whole-house ventilation strategies are also necessary, especially in tighter building envelopes. Increased outdoor air ventilation can effectively reduce indoor concentrations of many VOCs.16 However, it is important to note that ventilation typically increases building energy use 22 and is not highly effective for reducing semivolatile organic compounds (SVOCs), which tend to adsorb onto indoor surfaces rather than remain airborne.16 ASHRAE recommends that when air-sealing measures are implemented in a building containing unvented appliances, ventilation should be reassessed and augmented if necessary to maintain adequate indoor air quality.2
Addressing Backdrafting Risks in High-Performance Homes
A critical design consideration for architects is the risk of backdrafting. High airflow range hoods, while effective at removing cooking pollutants, can create negative pressure within a tightly sealed home. This negative pressure can potentially draw harmful carbon monoxide from other combustion appliances (e.g., furnaces, water heaters, fireplaces) into the living space through their flues or chimneys.8 This complex interaction between powerful exhaust systems and the building envelope's airtightness necessitates careful planning. Architects must consult with qualified MEP engineers and other professionals during the design and installation phases to properly size and integrate ventilation systems, ensuring that backdrafting is prevented, potentially through the incorporation of make-up air systems.8
Table 2: Recommended Ventilation Strategies for Gas Appliance Pollutant Control
This table provides concrete, quantitative design targets for architects, translating scientific recommendations into actionable performance metrics. It offers specific guidance that can be incorporated into design specifications and discussions with mechanical engineers, helping to bridge the technical depth gap for architects.
Integrating Filtration for Enhanced IAQ
While ventilation plays a crucial role in diluting pollutants, filtration serves as a distinct and highly effective strategy for actively removing contaminants from the air.
The Role of High-Efficiency Filtration for Particulate Matter
LBNL research explicitly states that filtration is significantly more effective than ventilation at controlling PM2.5 concentrations and their associated health effects.15 This is a critical distinction, as it means architects cannot rely solely on increased ventilation to address all indoor air pollution problems, particularly for particulate matter, which constitutes the most significant indoor health burden. ASHRAE recommends MERV-13 or better filtration for reducing infectious aerosol exposure, a standard increasingly adopted as a new baseline in building codes and guidelines.13 Cost-benefit analyses consistently demonstrate that air cleaning for PM2.5 control is highly cost-effective, offering substantial health benefits.13 ASHRAE is actively working to incorporate requirements for controlling indoor particle concentrations into its standards for all building types and climatic conditions, further emphasizing the importance of this strategy.13 This highlights the necessity of integrating robust filtration systems as a complementary, rather than substitutable, strategy for comprehensive IAQ.
Limitations of Ventilation Alone for Certain Pollutants
It is critical for architects to understand that ventilation alone has inherent limitations in addressing the full spectrum of indoor air pollutants. While increased ventilation helps dilute many volatile organic compounds (VOCs), it is significantly less effective for semivolatile organic compounds (SVOCs), which primarily reside on indoor surfaces rather than remaining airborne.16 Moreover, as previously highlighted, PM2.5-related health burdens are not highly sensitive to changes in ventilation rates.15 This means architects must recognize that simply increasing airflow will not solve all indoor air pollution problems, particularly for persistent particulates and certain surface-bound VOCs. This understanding mandates the inclusion of high-efficiency filtration as a distinct, necessary layer of protection, especially in tightly built homes where internally generated particulates and surface-bound VOCs can accumulate.
Monitoring and Alarms: Essential Safeguards
Beyond proactive design, equipping homes with appropriate monitoring and alarm systems provides essential safeguards and empowers occupants to manage their indoor environment.
Mandatory Carbon Monoxide Alarms
The installation of carbon monoxide (CO) alarms is a non-negotiable safety measure, strongly recommended by ASHRAE for all homes, irrespective of the heating fuel type used.2 These alarms provide critical early warning for a colorless, odorless, and potentially fatal gas, serving as a last line of defense against acute CO poisoning.
Considering Advanced IAQ Monitors for Comprehensive Protection
Beyond mandatory safety alarms, architects should consider integrating advanced indoor air quality monitors into their designs. While consumer IAQ monitors may not always detect ultrafine particles, they have proven useful in alerting occupants to significant PM2.5 sources, such as cooking events.19 These monitors can provide real-time data, empowering occupants to make informed decisions about ventilation and source control, and offering a proactive approach to maintaining healthy indoor environments. This approach moves beyond mere code compliance to a continuous, performance-based assessment of IAQ, enhancing the building's value and occupant well-being.
Collaboration with MEP Engineers and Qualified Professionals
The successful implementation of healthy building strategies, particularly concerning gas appliance emissions, necessitates close and early collaboration between architects, mechanical, electrical, and plumbing (MEP) engineers, and other qualified building professionals. Professional installation and annual maintenance by certified technicians are crucial for the safe and efficient operation of gas appliances.2 Furthermore, the selection and installation of high-airflow range hoods, essential for pollutant removal, requires expert consultation to prevent the dangerous phenomenon of backdrafting, which can draw carbon monoxide into living spaces.8 ASHRAE advocates for installer certification to ensure competence in these critical areas.2 The complex interactions between the building envelope, mechanical systems, and pollutant pathways underscore that architects cannot address indoor air quality in isolation. While architects lead the overall design, their ability to foster and integrate expert collaboration is paramount to achieving truly healthy indoor environments.
Building a Healthier Future
This report has illuminated the significant, often unseen, health impacts of fossil fuel combustion gas appliances in homes. The analysis has detailed how these appliances contribute to a complex array of indoor air pollutants, including nitrogen dioxide (NO2) and particulate matter (PM2.5), which exacerbate respiratory illnesses like asthma. Furthermore, the report highlighted the carcinogenic risks posed by volatile organic compounds such as benzene, notably from the continuous leakage of unburned natural gas, even when appliances are off. The critical role of moisture management was also underscored, revealing how the moisture byproduct of combustion, combined with tighter building envelopes, can create conditions conducive to mold growth and associated health problems.
Architects are uniquely positioned to mitigate these risks through informed design choices that prioritize occupant health. This includes advocating for and specifying source control measures, such as the transition to all-electric homes, thereby eliminating the continuous release of hazardous air pollutants. It also involves implementing robust ducted ventilation systems with high capture efficiency for kitchen exhaust, integrating advanced filtration for particulate matter throughout the home, and specifying essential monitoring and alarm systems to provide continuous oversight of indoor air quality.
By understanding the intricate dynamics of indoor air quality and the specific hazards associated with gas appliances, architects can move beyond conventional design to become leaders in creating truly healthy, high-performance homes. This leadership demands a commitment to continuous learning, fostering interdisciplinary collaboration with MEP engineers and building science specialists, and adopting a proactive approach to safeguarding occupant well-being. The future of residential design necessitates buildings that are not only energy-efficient and aesthetically pleasing but are fundamentally engineered and designed for optimal human health.
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