(Last Updated On: July 13, 2023)

Secondhand Smoke and Its Impact on Indoor Air Quality



air filter for pet allergies from dogs

By Becky Dotson

12 min read

Smoking has proven to be a dangerous habit. It can cause long-term health problems for anyone who has a history of smoking. But over the past several decades, the number of Americans who smoke has steadily decreased. The Centers for Disease Control and Prevention (CDC) puts the number of smokers in the U.S. now around 14 percent.

Unfortunately, even if you’ve never smoked a cigarette in your life, you can still end up develop health issues from it. That’s because secondhand smoke is dangerous and unhealthy, too.

secondhand smoke

Secondhand smoke, often referred to as environmental tobacco smoke, consists of a mixture of two types of smoke that come from burning tobacco: sidestream smoke, which emanates from the end of a burning cigarette, and mainstream smoke, which the smoker exhales. This noxious mixture contains over 7,000 chemicals, hundreds of which are toxic and about 70 can cause cancer.

Even though it’s not actively inhaled by those around, secondhand smoke still plays a significant role in indoor air pollution. Particles from secondhand smoke can easily mingle with dust and other pollutants in the air, significantly decreasing the quality of indoor environments. They are small enough to remain suspended in the air for hours, and some can even adhere to surfaces or furnishings, posing a risk for quite a long period.

Importantly, exposure to secondhand smoke isn’t merely a minor inconvenience. It’s a major public health issue. The U.S. Surgeon General has concluded that no risk-free level of secondhand smoke exposure exists. Even short-term exposure can potentially harm health, especially for people with pre-existing health conditions. Long-term exposure increases the risk of developing heart disease and lung cancer. For children, it can lead to sudden infant death syndrome, respiratory infections, ear infections, and more severe asthma. Hence, it’s crucial to understand, control, and ultimately eliminate secondhand smoke to improve indoor air quality.

What Is Secondhand Smoke Made Of?

Secondhand smoke, also known as environmental tobacco smoke, is a composite of two types of smoke that come from burning tobacco: sidestream smoke and mainstream smoke. Sidestream smoke comes from the end of a lit cigarette, cigar, or tobacco pipe. Mainstream smoke is the smoke that is exhaled by the smoker. This complex mixture contains over 7,000 chemicals, with hundreds of them being toxic and approximately 70 known carcinogens.

Some of the most toxic and harmful compounds found in secondhand smoke include formaldehyde, benzene, vinyl chloride, arsenic, and ammonia. Formaldehyde is a colorless gas with a strong, suffocating odor. It is commonly used in the production of resins, textiles, and wood products. Benzene is found in rubber, dyes, detergents, drugs, and gasoline and is known to cause leukemia and non-Hodgkin lymphoma. Vinyl chloride is used in plastics industry and is highly associated with liver, lung, and blood cancers. Arsenic and ammonia, on the other hand, can cause severe health issues even in small quantities.

Detecting and Measuring Secondhand Smoke Indoors

Detecting and measuring secondhand smoke indoors can be achieved through various methods. One common method is nicotine monitoring, which involves collecting air samples over a specific period, typically several days to a week, and then analyzing them in a laboratory for nicotine, a distinct marker of tobacco smoke. This method is generally reliable, but it requires specialized equipment and laboratory analysis, making it less accessible for general public use.

Another common approach is particulate matter (PM) monitoring. PM monitoring involves measuring the concentration of fine particles in the air (PM2.5) that are commonly associated with secondhand smoke. PM2.5 are tiny particles suspended in the air with a diameter of 2.5 micrometers or less, small enough to be inhaled into the respiratory tract. High levels of these particles can be an indicator of secondhand smoke.

In recent years, the use of indoor air quality sensors that can detect and quantify levels of pollutants, including those from secondhand smoke, has become increasingly common. These devices can provide real-time data about indoor air quality and are becoming more affordable and accessible to the general public.

Interaction of Secondhand Smoke with Other Indoor Air Pollutants

Secondhand smoke doesn’t exist in isolation in indoor environments. It often interacts and combines with other indoor air pollutants, leading to a complex and potentially more harmful mix of pollutants. These other pollutants can come from a variety of sources, such as volatile organic compounds (VOCs) emitted from paints, solvents, and cleaning supplies, as well as emissions from cooking, heating, and ventilation appliances.

When secondhand smoke particles mix with VOCs, for instance, they can undergo chemical reactions, leading to the formation of secondary organic aerosols. These aerosols further degrade indoor air quality and can cause respiratory issues and other health problems. Likewise, secondhand smoke can interact with nitrogen oxides from cooking or heating appliances to form ground-level ozone, another harmful pollutant.

Understanding the interactions between secondhand smoke and other indoor air pollutants is critical to accurately assess indoor air quality and the associated health risks. It helps to emphasize that efforts to improve indoor air quality need to consider all sources of pollution, not just secondhand smoke.

Health Risks Associated with Secondhand Smoke Exposure

Secondhand smoke is a hazardous cocktail of over 7,000 chemicals, including hundreds of toxins and around 70 carcinogens. These chemicals can cause or contribute to a plethora of health problems in both immediate and long-term contexts.

The immediate health effects of secondhand smoke exposure are quite noticeable. They include eye irritation, headache, cough, sore throat, dizziness, and nausea. These symptoms can be particularly troubling for individuals with pre-existing health conditions. For instance, people with asthma may experience exacerbated symptoms and more frequent and severe asthma attacks when exposed to secondhand smoke.

Long-term exposure to secondhand smoke can have devastating health effects. It can cause or contribute to serious respiratory conditions such as bronchitis and pneumonia. Furthermore, secondhand smoke significantly increases the risk of heart disease and lung cancer. Studies suggest that exposure to secondhand smoke boosts the likelihood of heart disease by 25-30% and the risk of lung cancer by 20-30%.

Long-term Health Effects on Non-smokers and Comparison with Direct Smoking

While the dangers of direct smoking are well-documented, the perils of secondhand smoke, especially for non-smokers, deserve equal attention. Non-smokers who live or work around smokers inhale the same harmful chemicals as smokers do. Even though their level of exposure might be less compared to direct smokers, the health risks are still considerable and accumulate over time.

Prolonged exposure to secondhand smoke can lead to heart disease and lung cancer, two of the leading causes of death worldwide. Research shows that non-smokers exposed to secondhand smoke at home or work increase their risk of developing heart disease by 25–30% and lung cancer by 20–30%. The same exposure also increases the risk of stroke. Together, these diseases cause over 400,000 deaths annually in the United States alone. Thus, the impact of secondhand smoke on non-smokers can be as severe as it is on those who smoke directly.

The Effect of Duration of Exposure on Health Outcomes

The length and frequency of exposure to secondhand smoke significantly affect health outcomes. A simple rule of thumb is: the longer and more frequently you are exposed to secondhand smoke, the higher your risk of health problems. This is because the harmful substances in the smoke build up in the body over time.

Long-term exposure to secondhand smoke has been associated with chronic health conditions like heart disease and lung cancer. These risks are cumulative, which means that they increase over time with continued exposure. Even intermittent exposure can lead to health issues over time, highlighting the need for comprehensive measures to avoid secondhand smoke.

Safe Level of Exposure to Secondhand Smoke Indoors

When it comes to secondhand smoke, the consensus among health organizations, including the U.S. Surgeon General and the World Health Organization, is that there is no safe level of exposure. Every whiff of secondhand smoke carries harmful substances that can lead to health problems.

Even low levels of secondhand smoke can be harmful. This is especially true for vulnerable groups such as children, the elderly, and individuals with certain pre-existing health conditions. Therefore, the most effective strategy to protect non-smokers from the harmful effects of secondhand smoke is to eliminate smoking in indoor spaces completely.

Impacts of Secondhand Smoke on Children, Infants, and Pets

The harmful effects of secondhand smoke extend to more than just adult non-smokers; they also significantly impact children, infants, and pets. These groups are especially vulnerable due to their smaller size, faster breathing rates, and, in the case of children and infants, developing bodies and immune systems.

Exposure to secondhand smoke in children and infants can lead to a host of health issues. These include sudden infant death syndrome (SIDS), acute respiratory infections, ear problems, and exacerbated asthma. Studies have also found that children exposed to secondhand smoke have a higher risk of developing behavioral and cognitive problems later in life.

Pets, another integral part of many families, are also affected by secondhand smoke. Just like humans, they can suffer from a range of health issues due to secondhand smoke, such as respiratory problems, allergies, and even certain types of cancer. For example, cats can be at risk of malignant lymphoma and oral cancer because they groom themselves by licking, which can lead to the ingestion of smoke particles that land on their fur.

Vulnerable Populations and Economic Impacts

There are several groups more susceptible to the harmful effects of secondhand smoke indoors due to various factors, including age, pre-existing health conditions, and socioeconomic status.

Children and infants, as previously discussed, are particularly vulnerable due to their developing immune systems and bodies. The elderly, another at-risk group, are more susceptible due to their typically weaker immune systems and the potential presence of chronic illnesses. Pregnant women exposed to secondhand smoke face risks not only for themselves but also for their unborn babies. Exposure to secondhand smoke can lead to a variety of complications, including premature birth, low birth weight, and even developmental issues as the child grows.

People suffering from respiratory conditions, such as asthma or chronic obstructive pulmonary disease (COPD), are also more vulnerable to secondhand smoke. The smoke can aggravate their symptoms, leading to more severe health issues and decreased quality of life.

Examination of How Secondhand Smoke Contributes to the Global Burden of Disease

Secondhand smoke plays a significant role in the global burden of disease. The World Health Organization (WHO) estimates that around 1.2 million people die each year due to secondhand smoke exposure. Secondhand smoke is also responsible for about 10% of all tobacco-related deaths.

In addition to mortality, secondhand smoke also contributes significantly to morbidity worldwide. It leads to a range of diseases, including ischemic heart disease, lower respiratory infections, asthma, and lung cancer. This not only reduces the quality of life for those affected but also places a significant strain on health services.

Prevention and Mitigation Strategies

Ventilation can play a significant role in mitigating the effects of secondhand smoke indoors, but it should not be considered a panacea. Properly functioning ventilation systems can help disperse smoke particles and decrease their concentration in the air. However, ventilation alone is often insufficient to remove all the toxins released by tobacco smoke.

There are different types of ventilation, including natural ventilation (opening windows and doors), mechanical ventilation (such as fans and exhausts), and air conditioning systems. While these methods can dilute the concentration of smoke in a room, they cannot eliminate the risk entirely. It is crucial to remember that the goal is to minimize exposure, not merely to reduce it.

Effectiveness of Air Purifiers in Eliminating Secondhand Smoke 

Air purifiers can be an effective tool in combating secondhand smoke indoors, but their effectiveness can vary significantly based on factors such as the type of purifier, the size of the room, and the intensity of smoke exposure.

Air purifiers equipped with High Efficiency Particulate Air (HEPA) filters are among the most effective at removing particulate matter from the air, which includes the tiny particles found in secondhand smoke. Some air purifiers also include activated carbon filters, which can help remove the gaseous pollutants that contribute to the smell of secondhand smoke.

While air purifiers can aid in improving indoor air quality, they should be considered a supplement to other mitigation strategies, not a solution in themselves. The most effective way to protect non-smokers from the dangers of secondhand smoke is to prevent smoking indoors altogether.

Recommendations for Landlords, Property Managers, and Individuals to Limit Exposure to Secondhand Smoke

Limiting exposure to secondhand smoke indoors requires a concerted effort from all parties involved – landlords, property managers, and individuals alike. Landlords and property managers can adopt smoke-free policies for their properties, which can significantly reduce the risk of secondhand smoke exposure for tenants. This may involve designating certain areas as smoking zones far away from common areas and living spaces.

Individuals can also play an active role in minimizing exposure to secondhand smoke. If they are smokers, they can choose to smoke outside or in designated smoking areas. Non-smokers can advocate for smoke-free environments and support policies that limit smoking in shared indoor spaces. It is also beneficial to communicate with family members, roommates, or neighbors about the risks of secondhand smoke and establish boundaries regarding smoking.

Emerging Technologies Being Developed to Combat Secondhand Smoke and Improve Indoor Air Quality

Innovation is an essential tool in the ongoing fight against secondhand smoke. Emerging technologies are being developed to help detect, quantify, and eliminate secondhand smoke in indoor environments. These include advanced air purifiers equipped with sensors to monitor air quality in real-time and smarter ventilation systems that can adjust based on the level of pollutants in the air.

New materials are also being developed for use in indoor environments that can help to absorb or neutralize smoke and other pollutants. For instance, photocatalytic materials use light to catalyze a chemical reaction to break down certain organic pollutants.

Public health strategies are also evolving. For example, community-based interventions and smoking cessation programs are becoming more tailored to specific populations. These interventions are not only aiming to reduce smoking rates but also focus on minimizing exposure to secondhand smoke in homes and other indoor spaces.

These innovative technologies and strategies provide hope for a future where everyone can enjoy clean, smoke-free air in their indoor environments.

The Recap

Addressing secondhand smoke as a critical source of indoor air pollution is imperative for public health. Secondhand smoke poses a range of serious health risks, from respiratory diseases to lung cancer, and negatively impacts the quality of life for millions of non-smokers worldwide. It’s not just an issue for smokers; it’s a societal issue that affects us all, particularly the most vulnerable among us, including children, the elderly, and those with pre-existing health conditions.

Ultimately, the fight against secondhand smoke and its contribution to indoor air pollution is a collective responsibility. It’s a fight that involves everyone – from individuals and families to governments and international organizations. By working together, we can create healthier, smoke-free indoor environments for all.