Indoor Air Quality in Rental Properties: A Landlord/Tenant Guide

By one estimate, modern citizens spend nearly 90% of their life indoors – be that their home or place of business. While this comes with a refined sense of comfort from modern air conditioning, this overabundance of indoor time also comes with some noteworthy dangers.

In crowded urban centers, time spent indoors can feel like a respite from the acrid, pollutant-filled air that hangs over city streets. But according to Environmental Protection Agency (EPA) studies, indoor air may contain between 2 and 100 times as many pollutants as comparable outdoor air. As it turns out, indoor spaces have a tendency to trap such noxious fumes, potentially leading to health risks through long-term exposure.

City-dwellers aren’t the only folks who should be alarmed by this troublesome prospect. Tenants in rural and suburban areas should be equally as alarmed at the potential for decreased indoor air quality (IAQ). Even landlords have a thing or two to learn about preventing these indoor air pollutants from permeating their apartments and office spaces.

From common pollutants and mitigation procedures to regulations governing indoor air quality, there’s a lot to learn about this unseen health deterrent. But with the information contained in this landlord and tenant’s guide to indoor air quality, you’ll be able to succinctly learn the basics of this critical domain and plan for a future where everyone can breathe better while indoors.

Common Indoor Air Pollutants

Whether in an urban or rural setting, there are a variety of indoor air pollutants that tenants and landlords alike should be fully aware of. Each of these air pollutants behaves differently and may affect different people with different degrees of severity (especially if they possess a pre-existing condition that affects their breathing).

In most cases, only one or two of these pollutants will be present in a given living space or office. However, any one of these pollutants can lead to acute illness if inhaled at heightened levels over a specific period of time. As such, each of these pollutants should be taken as a serious threat to health and safety if they are not addressed in a timely manner.

Mold and Dampness

As is commonly understood, mold in its many forms possesses a risk to the wellbeing of humans and their pets. Often, indoor mold issues are caused by a preponderance of moisture problems either in the air or within a constructive element of the dwelling (such as the walls, ceiling, or floor). Even residual dampness can result in molding, so it is always important to address moisture before it becomes it precipitates a larger, more harmful problem.

The California Department of Public Health provides some insight into the potential risks that come with leaving moisture and mold unattended within an indoor space. Among other potential outcomes, they note that “the development of asthma, allergies, and respiratory infections” are among the most severe for average citizens. However, for citizens with existing breathing difficulty, they note that mold and dampness cause trigger “asthma attacks… increased wheeze, cough, [and] difficulty breathing.”

Broadly speaking, there is not a single proven method to fully eliminate moisture in an indoor space (especially in regions where ambient moisture is high or during humid seasons such as summer). However, there are methods for controlling moisture – such as a dehumidifier – that can help cut down on the chance of mold growth.

In all cases, the key is to act quickly and decisively when it comes to removing moisture-causing elements and eliminating any mold as soon as it appears. Standing water (from flooding or a water main leak) should be soaked up immediately and residual moisture should be evaporated with a fan. Moldy materials should be wiped with a strong cleaner or thrown away if they are not salvageable. Make sure to refer to the Department of Health’s fact sheet for additional information on mold remediation.

Secondhand Smoke

For several decades, the effects of secondhand smoke (that is, tobacco product smoke inhaled by a non-smoking party) have been well-understood to be particularly harmful. Though the effects are less severe than direct smoking, secondhand smoke inhalers are still exposed to the nearly 7,000 chemicals packed into an average cigarette.

Suffice to say, exposure to secondhand smoke can lead to severe health outcomes. According to the Center for Disease Control (CDC), such exposure can lead to an increased risk for stroke, heart disease, and lung disease (even if the secondhand smoke exposure is not lifelong). In children, secondhand smoke has even been connected to severe asthma attacks, respiratory and ear infections, and sudden infant death syndrome (SIDS).

Indoor smoking is less common today due to changes in public perceptions of the practice, as well as a rise in non-smoking rental contracts. Even in locations where indoor smoking is still allowed or practiced, all adjacent parties – landlords and tenants alike – should remain mindful of the long term cost associated with the practice.

Simply put, the best way to avoid the risks of secondhand smoke is to eliminate the risk at its source. In other words, tenants wishing to avoid secondhand smoke should not live with smokers. Similarly, landlords looking to avoid the cost and maintenance needed to accommodate smokers should not rent to them in the first place.

Lead and Lead-based Paints

For many decades, lead – a naturally occurring metal – was used as an additive in paint in order to accelerate drying, increase durability, and maintain color when exposed to sunlight. Since 1978, though, the US and many other countries have banned the use of lead-based paints because of the well-documented health effects lead can have on people (especially children) when inhaled or ingested.

Even as federal efforts continue to eliminate all lead-based paint across the nation, thousands of dwellings remain coated in the toxic material. As such, thousands of children remain susceptible to lead poisoning when the lead-based paint begins to chip. This type of poisoning occurs when non-soluble lead accumulates in the blood, leading to “stunted growth, lower IQ, behavior and learning problems, anemia, and hearing problems” according to the CDC.

There is no safe level of lead-based paint exposure according to the CDC. As such, tenants should avoid dwellings that contain lead-based paint in any volume if they are fiscally able to do so. Similarly, landlords who purchase property with lead-based paint should expend whatever resources necessary to eliminate it safely and fully before renting said property out.

Among the several most common air quality pollutants, lead-based paint exposure is among the most preventable. All efforts to avoid it and eliminate it should be undertaken in the name of making a space livable by modern standards.

Pests and Pesticides

For a variety of reasons, insects and other comparable pests may attempt to take up residence within an indoor dwelling. For primary sanitation reasons, these pests should be addressed as soon as possible to prevent an infestation from forming. That being said, any chemical-based prevention method should be undertaken with care.

While common pesticides may be effective in addressing common pests such as cockroaches, the use of these sprays can cause harm to tenants who inhale its aerosolized form. The EPA has identified several degrees of harm associated with these pesticides, ranging from minor skin and eye irritation to long-term hard, such damage to the endocrine and nervous systems, and cancer.

Tenants who are attempting to eliminate pests from their dwelling should only use chemical sprays in areas that are well-ventilated and free of other residents when applied. Also, tenants should consider wearing a face mask or barrier while applying the spray. Contaminated or inadequate ventilation systems are often a cause of decreased indoor air quality.

Landlords, on the other hand, should consider alternative methods of eliminating pests without introducing harmful chemicals into their tenant’s living or working environment. Such methods include an integrated pest management solution, which limits pest entry into a dwelling through non-chemical means. As a rule, routine pest spray usage is broadly discouraged due to its ability to accumulate in a space over an extended period of time.


Radon is a naturally-occurring gas that has been documented in all corners of the United States and in some areas around the world. This gas – which is radioactive by nature – is formed when uranium deposits found deep in the Earth begin to decay, which in time allows the gas to percolate upwards and outwards through the soil.

In regular circumstances, radon is off-gassed into the air, where it dissipates without causing harm to biological life. However, homes built over moderate-to-high concentrations of the gas run the risk of collecting the gas within the impermeable walls and floors of the structure. In many cases, this radon gas enters a home through holes or cracks in its foundation.

According to current EPA estimates, radon gas exposure has been linked to the second-leading cause of lung cancer in the US, with its 21,000 deaths trailing only smoking-related lung cancer. This is particularly troubling given that radon cannot be detected by sight or smell, as with other common air quality pollutants.

As such, specialized testing equipment must be used by landlords and tenants who wish to identify their dwelling’s radon contamination level. Radon testing kits are readily available and fairly affordable for both small and large scale testing. Also, some digital testing devices are available today for long-term testing in a known radon-afflicted structure.

Currently, the EPA sets its radon “action level” at 4 pCi/L (picoCuries per liter of air). If preliminary testing reveals a radon level over this volume, tenants should seek out immediate redress through their landlord. Landlords, in turn, should make plans to install some type of proven radon reduction system (likely in the basement or foundation of the affected building). Healthy homes are a joint effort.

Miscellaneous Pollutants

There are several other noteworthy air quality pollutants that may afflict an indoor structure, depending primarily on its age and intended use. Asbestos is one of the best known auxiliary air pollutants, deriving primarily from its tendency to degrade when used as insulation. Made from long, fibrous strands of silicate material (such as glass), this material has been connected to a variety of lung conditions in recent conditions. These pollutants can have a huge impact on environmental health.

The majority of buildings built before the 1980s in the US used asbestos-based insulation to some degree. However, efforts have been made to remove the material from public structures since that time. Private landlords should make an effort to remove the material as soon as possible, while tenants should always ask about the presence of asbestos when signing contracts.

Formaldehyde is another common air quality pollutant that can be found in indoor dwellings. While the hazardous chemical can be produced by smoking, it is also commonly produced by a certain type of building materials as they age. In particular, this includes pressed wood products such as plywood and particle board that use urea-formaldehyde resins as a binding agent.

Because it is colorless and odorless, formaldehyde gas can be difficult to detect without proper equipment. Even so, it has been shown to cause watery eyes, burning sensations in the eyes and throat, nausea, and breathing difficulty. Also, suffers of asthma are more likely to suffer more frequent and more severe attacks in spaces where formaldehyde gas is sequestered.

Special Considerations for Offices

While many of the information regarding air quality pollutants in this guide apply evenly across apartments, offices, and other rented spaces, office spaces, in particular, require several special considerations connected to their use on an industrial scale. Certain risks related to the pollutants described above increase with scale, so offices can become especially hazardous in short order if not properly attended to.

First and foremost, office air distribution systems require proper maintenance in order to function properly and eliminate potentially dangerous pollutants. Whether you are building a new structure or remodeling an existing space, be sure that your new HVAC system will fit both the design and layout of the modified space. Also, be sure that your chosen HVAC system is designed to handle as many people as you expect to a regular house in the office.

Often, HVAC systems will draw air from the outdoors and filter it as it is cooled or heated. While this intake system is being set up, ensure that it is at a proper level such that it is drawing proportionally cleaner air. In addition, make sure that any filters installed into this system are rated for your expected level of urban pollution and are changed on a regular basis.

If all of these factors are maintained, your office will be much more able to combat the risk possessed by outdoor pollutants enter and accumulating in your office space. Regular testing (as described below) should be undertaken regularly in order to keep track of pollutant levels over time. If one or more pollutants exceed reasonable bounds, then you should act as soon as possible to diagnose the cause and resolve it.

Addressing Indoor Air Quality Problems

For Tenants

Broadly speaking, tenants should always share their concerns about air quality pollutants with their landlord/building owner. In many cases, a landlord will be able to provide guidance for what steps should be taken to resolve the problem in that particular apartment or office. Also, this tiered process allows the landlord to document when the problem originated and act accordingly if it persists.

However, the landlord need not be contacted immediately in all cases, especially if a tenant is unsure about the precise nature of their air quality contaminant. Several preliminary steps may be taken in order to provide more information to the landlord, should that step be needed in the long run. As always, tenants with a strong suspicion about their indoor air quality should immediately contact their landlord.

First, if pollutants (especially mold and moisture) appear in a bathroom space, try to use the built-in shower fan to draw ambient moisture in the room away from the afflicted areas. Similarly, a built-in stove fan should always be turned on when using the cooktop space. This can prevent bothersome smoke or steam from propagating through the apartment.

Also, if you notice a higher-than-average volume of irritants in the air (such as pollen during the springtime), consider purchasing and using a high-efficiency vacuum cleaner with a HEPA filter. This can prevent air contaminants from repeatedly re-entering the air from a carpeted floor.

Finally, if preliminary resolution methods are ineffective, be sure to swiftly contact your landlord. While doing so, be sure to follow the procedures set out in your lease agreement (if any). Once you have reported the problem, be sure to follow up with the landlord and insist that they act during the time period required by applicable local and state laws.

For Landlords

Even without a reported problem from a tenant, landlords should always be proactive in identifying and resolving air quality pollutants in their rentable spaces. In many cases, such proactive measures – including routine testing – are required by local and state laws, making non-compliances a finable offense.

Some pollutants are easier to resolve, in relative terms. In most instances, moisture and mold growth can be resolved by eliminating the source of the moisture and minimizing the ambient moisture already in a space. Leaky pipes should always be tended to swiftly, and areas affected by any remaining moisture should be supplemented with fans and dehumidifiers.

Pollutants such as lead-based paint or radon contamination should (ideally) be addressed before a space is put on the market for rent. This is because it is much more difficult to address these problems while an occupant is living or working in the contaminated space. If these are necessary, however, proper testing should first be implemented, followed by appropriate cleanup and mitigation efforts.

In some cases, the very nature of a building may make it difficult to fully eliminate the source of a certain air pollutant. For example, an urban apartment building converted from an early 20th-century hotel may be predisposed to some degree of mold, due to its age. In this case, you would include information such as a “mold addendum” to your lease agreement and require informed consent from your renters.

In many states and local jurisdictions, specialized laws and housing codes describe precisely how air quality contaminants should be handled and what (if any) liability landlords and tenants have to address the problem in a mutually beneficially manner. In addition, these regulations also generally detail fines and punishments for landlords that do not meet these requirements, as determined by a regulating authority.

For the purposes of this guide, only some of the many legislative measures found throughout the nation will be detailed. Many urban jurisdictions maintain an even more extensive portfolio of housing regulations. For more information on your specific requirements, consider visiting the website for your state Attorney General or city housing authority.

Disclaimer: none of the following information designed to serve in lieu of professional legal advice. As always, if you have questions about your responsibilities and liabilities under current local, state, and federal housing laws, consult with a lawyer.

Broad Legislation

The Fair Housing Act of 1968 and the Americans with Disabilities Act of 1990 are two sets of federal legislation that are broadly designed to set the standards for preventing discrimination in American public and private housing. In the context of air quality pollutants, this includes individuals who have or may acquire a disability through long-term residence in a rented space.

In general, the Fair Housing Act lays the groundwork for principled prevention of discrimination in American housing contracts. This includes safeguards to prevent landlords from falsely preventing certain tenants from living in their available properties, as well as providing false information regarding the property’s precise nature.

Moreover, the Fair Housing Act set preliminary standards for preventing individuals with disabilities from being denied housing based upon an unwillingness to provide reasonable accommodations. The definitions governing “reasonable accommodation” were further expanded and cemented through the later Americans with Disabilities Act.

This act broadens the classes and definitions surrounding “disability,” allowing it to include afflictions relating to breathing. In the context of this guide’s topic, this means that a landlord cannot intentionally refuse to address a known air quality contamination such that would make the space unlivable for the tenant. In light of this, landlords must be able to make modifications to an apartment to address the problem or else run the risk of running afoul with local enforcement authority.

If a tenant is seeking redress under this federal legislation, they may consult the Department of Housing and Urban Development’s website for proper procedures.

Housing Codes

Sometimes referred to as housing maintenance codes, housing codes are often the most direct set of regulations governing the minimum standards for housing conditions within a specific jurisdiction. Content-wise, these codes often set out the precise mechanisms through which contaminant testing (in the air and other mediums) as well as how perceived problems with these factors may be remedied.

Most US states set base-level housing codes to meet the standards described in contemporary federal legislation. These rules and regulations cover the whole state, including areas with more specific housing codes. Often, infractions in these codes are enforced by a state-sanctioned body (usually a state-run department or state-licensed housing authority).

Many cities (and even some large suburbs) also maintain local housing codes, specifying standards for all rental properties within that city’s jurisdiction. These codes are almost always more severe than those prescribed by the state and are often designed to address unique problems within that particular urban environment.

Regardless of the specific region covered by a particular housing code, they are always enforced publicly. Depending on the division of power within your state, this might be carried out by a state housing department, the state Attorney General, a state-certified housing board, or city-wide housing authority.

When infractions under a housing code are identified, the effected landlord is often warned and given a period of time to fix the problem. If the problem is not fixed properly during this prescribed time period, the enforcement authority is often able levy additional warnings or fines. In cases of willful negligence, law enforcement may also be brought in to enforce a punishment regimen.

Landlord-Tenant Laws

Separate from housing codes, landlord-tenant laws set out the rights and responsibilities of all parties involved in the rental of an apartment or office space. Often, these laws detail what privileges each party possess during the terms of their contract together (many of which are detailed within the lease agreement proper).

Content-wise, these laws often include what measures the tenant must take to keep an apartment secure and in good repair. On the other hand, these laws often require landlords to make themselves readily available for repairs (if they do not outsource such repairs).

As with housing code enforcement, different levels of these agreements exist to cover state and local jurisdictions. This is most noteworthy in the case of rent control measures, which are sometimes instituted by cities in order to cap how much tenants can be charged for rent over a specified period of time. These stabilization measures are often designed to corner an otherwise localized housing crisis, making their enforcement critical.

An Indoor Air Quality Checklist

For Tenants

Before signing into a lease agreement for an apartment or office, there are several important steps you should take in order to ensure that your new rental unit meets all of the relevant legal and practical standards for air quality. For best results, be sure to use these steps each and every time you move into a new location or begin working with a new landlord:

  1. Always Read the Fine Print – Housing contracts (especially in cities) can be particularly long and complicated, making it difficult to discern pertinent details. While your landlord should go over the full contract with you if you request it, be sure to take time to read it yourself before signing it. This is doubly the case if you have a pre-existing condition that may be aggravated by an air quality contaminate.
  2. Ask Questions – Don’t be afraid to ask your landlord about the conditions of their rental space, even if doing so may feel uncomfortable. This includes over the language of the contract, which may require further legal advice to unwind in its entirety. If you have a certain sensitivity, make this known to the landlord in case further action is needed later on to address a new air contaminant problem.
  3. Check the Records – If they are available from your local housing authority, check if your landlord currently has any significant complaints against them (both in general and regarding the air quality on their properties). Similarly, check online for complaints from former renters to see if problematic trends appear. In either case, these may act as warning signs that a landlord is unwilling to address air contaminant problems, putting you at risk going forward.

For Landlords

In accordance with proper laws and regulations, landlords must also undertake certain degrees of certification for their properties before putting them on the market. Depending on requirements in your jurisdiction, this may include routine testing for common air quality pollutants as well as proper notification regarding the presence of ongoing contaminants.

While this list shouldn’t be taken as a definitive, landlords can use these key steps to make progress towards making their property habitable:

  1. Perform Routine Tests – As a matter of due diligence, all landlords should routinely perform certified tests for common contaminants found in their area. While this should absolutely include tests for mold problems and pest infestations, you may also elect to test for radon (if it is not already required in your area). Always keep the results of these tests on record, both as a matter of proper record keeping and in order to provide evidence against accusations of improper maintenance. Also, make sure you have carbon monoxide detectors and rules for smoke-free spaces.
  2. Provide Proper Documentation – Within the language of your leases, be sure to clearly and concisely explain any risks that the renter may take upon themselves by living or working on your property. In some cases, such allowances are legal if the contaminant level falls within negligible bounds and the renter is provided proper informed consent. Also, be sure to include any language required by local housing laws pertaining to broadly known contaminants associated with the urban environment.