AP: Lesson - Indoor Air Pollution (Topic 7.5) 📖

⏳ Estimated Reading Time: 8 - 10 minutes

Learning Objective

Identify and describe the effects of indoor air pollutants.

 

Indoor Air Pollution

A house with various household items and activities that contribute to indoor air pollution. Surrounding the house are labeled circles containing images of mold, cigarette smoke, dust mites, pet dander, pollen, mildew, chemicals from cleaning products, food being cooked, and combustion from heating systems.
There are many places in a home where indoor air pollutants can accumulate.

Indoor areas can also have their own form of air pollution.  Air pollution inside can be problematic because we are building houses more airtight to make them more energy efficient, which means that the pollutants are stuck inside and cannot get out easily.  

Indoor air pollutants can be classified as....

  • natural - pollutants originating from natural sources
  • anthropogenic - pollutants resulting from human activities
  • asphyxiants - gases that can cause suffocation by displacing oxygen in the air
  • particulates - fine particles suspended in the air
  • combustion - burning, which releases pollutants into the air

Indoor air pollutants can occupy more than one category. 

Explore the air pollutants presentation below. Do you think you might have any of these in your house? If you have any of these in your house, which categories do they occupy? Do you have any asphyxiants? (I hope not!)

 

Essential Knowledge

Carbon monoxide is an indoor air pollutant that is classified as an asphyxiant.

Indoor air pollutants that are classified as particulates include asbestos, dust, and smoke.

Indoor air pollutants can come from natural sources, human-made sources, and combustion.

Common natural sources of indoor air pollutants include radon, mold, and dust.

Common human-made indoor air pollutants include insulation, Volatile Organic Compounds (VOCs) from furniture, paneling, and carpets; formaldehyde from building materials, furniture, upholstery, and carpeting; and lead from paints.

Common combustion air pollutants include carbon monoxide, nitrogen oxides, sulfur dioxide, particulates, and tobacco smoke.

Common pathways through which radon gas can enter a home.
There are many ways radon can seep into homes. It most commonly enters homes through basements and crawl spaces.

 

Let's talk a little more about radon, specifically Radon-222. Radon is a naturally occurring radioactive gas that is colorless, odorless, and tasteless. 

Radon results from the decay of uranium present in certain rocks and soils. Specific areas of the United States are known to have higher levels of radon than other areas. The concentration of radon gas that reaches the surface of the earth and can enter our houses is related to how much is present in the local soil and rocks. Areas with large amounts of granite are associated with higher levels of radon. 

Radon can enter our houses dissolved in groundwater and then pumped into our homes.  When radon seeps into buildings, it can accumulate in enclosed spaces, especially basements and crawl spaces. Radon-contaminated building materials are also sometimes used in construction. 

The best way to mitigate exposure to radon is to prevent it from entering and remove it if it does get inside. Inhalation of radon poses health risks, which is why testing for radon levels in homes is crucial to ensure safety and mitigate potential health hazards. More information about radon can be obtained from the EPA.

 

Essential Knowledge

Radon-222 is a naturally occurring radioactive gas that is produced by the decay of uranium found in some rocks and soils.

Radon gas can infiltrate homes as it moves up through the soil and enters homes via the basement or cracks in the walls or foundation. It is also dissolved in groundwater that enters homes through a well.

 

Health Effects

Indoor air pollution can cause a slew of health effects. Below are some of the most common effects of indoor air pollution. Have you ever experienced these effects from indoor air pollutants?

🫁 Respiratory Disease (click to reveal)

Chronic exposure to indoor air pollutants can contribute to respiratory diseases.

 

🤯 Headaches (click to reveal)

Some pollutants may lead to headaches, dizziness, and fatigue.

 

😮‍💨 Asthma Aggravation (click to reveal)

Exposure to indoor air pollutants can cause asthma. And for those who already have asthma, exposure to indoor pollutants can worsen symptoms.

 

👁️ Irritation (click to reveal)

Common symptoms associated with indoor air pollutants are nose bleeds, chronic sinus infections, and skin, eye, nose, and/or throat irritation. 

 

🫀 Heart Disease (click to reveal)

Prolonged exposure may increase the risk of heart disease.

 

😷 Cancer (click to reveal)

Long-term exposure to asbestos and organic chemicals (like those found in pesticides) can cause cancer.

Radon exposure over many years can lead to lung cancer. Symptoms don’t appear immediately. Instead, health problems manifest after many years. When you breathe in radon, it gets trapped in your lung lining and emits radiation. This prolonged exposure damages lung cells, increasing the risk of lung cancer. Symptoms may include a persistent cough, shortness of breath, wheezing, coughing up blood, chest pain, or unintentional weight loss. If you experience any of these, consult your doctor.

In fact, radon is the second leading cause of lung cancer after cigarette smoking. Approximately 21,000 people die annually from radon-related lung cancer.

While lung cancer is the primary concern, some research suggests a link between radon and other cancers, such as childhood leukemia. However, the evidence for this association isn’t as clear.

Unfortunately, there are no routine medical tests to detect excessive radon exposure. 

 

🥴 Cognitive Defects (click to reveal)

Although less common, long-term exposure can impact cognitive function, a loss of balance and memory, chronic fatigue, and difficulty speaking.

 

Indoor air pollutants tend to have a larger effect on very young children, the elderly, people with respiratory or cardiac issues, and people with compromised immune systems. Because exposure to indoor air pollutants can be much longer than outdoor air pollutants, it’s wise to have a handle on the quality of air inside a building.

We have coined a term for places with large amounts of indoor air pollutants: sick building syndrome. When more than 30% of the people in a building complain of the same symptoms, the building is expected to be the cause. When a building is determined to be a sick building, you can identify the cause and remedy the situation (replace air vents, install an air circulation system, allow fresh air in, etc.). If you can’t find the cause, but many people are complaining of the same symptoms, it is likely that there are multiple causes, and it might be more difficult to remedy the situation.

 

Essential Knowledge

Exposure to radon gas can lead to radon-induced lung cancer, which is the second leading cause of lung cancer in America.

 

Preventing Indoor Air Pollution

There are a number of actions that can be taken to reduce indoor air pollutants. Below are a few ways we can reduce indoor air pollutants. Do you have any of these in your house? Because my son and I are asthmatic, we have HEPA air purifiers in most rooms in our home. We also open the windows on clear days to allow fresh air into our home. We seal our paints and store them in the garage.

🪟 Regular Ventilation (click to reveal)
        • Ensure proper ventilation by opening windows and using exhaust fans. Fresh outdoor air helps dilute indoor pollutants.
        • Consider installing mechanical ventilation systems like exhaust fans, air exchangers, or whole-house ventilation systems.

 

🚬 Identify Pollutant Sources (click to reveal)
        • Identify and address specific sources of pollution.
        • Common sources include tobacco smoke, household cleaning products, and gas stoves.
          • Smoking indoors significantly degrades air quality. Encourage smokers to smoke outside.
          • Store chemicals, paints, and solvents in well-sealed containers away from living areas.
          • Regularly service and maintain appliances like gas stoves, heaters, and air conditioners to prevent emissions.

 

🖌️ Use Low-VOC Products (click to reveal)
        • Opt for low-VOC (volatile organic compound) or no-VOC paints, cleaning supplies, and other household products.

 

🍳 Properly Maintain Appliances (click to reveal)
        • Regularly service and maintain appliances like gas stoves, heaters, and air conditioners to prevent emissions.

 

🪴 Indoor Plants (click to reveal)
        • Indoor plants can help improve air quality by absorbing pollutants and releasing oxygen.
        • Some effective plants include snake plants, peace lilies, and spider plants.

 

💨 Air Filters and Purifiers (click to reveal)
        • Use HEPA filters in air purifiers and HVAC systems to trap particles like dust, pollen, and pet dander.
        • Activated carbon filters can adsorb gases and odors.

 

🚰 Control Humidity (click to reveal)
        • High humidity can lead to mold growth and dust mites. Use dehumidifiers if needed.
        • Address leaks and water damage promptly to prevent mold growth.

 

🧼 Regular Cleaning (click to reveal)
        • Dust and vacuum surfaces, carpets, and upholstery to reduce dust mites and allergens.
        • Microfiber cloths trap more dust and particles than regular cloths.

 

☢️ Radon Testing (click to reveal)
        • Test your home for radon levels and take necessary steps if levels are high.

 

👩🏻‍🏫 Education (click to reveal)
        • Educate family members about indoor air quality and involve them in maintaining a healthy environment.

 

Indoor air pollution continues to gain notoriety as more and more homes and buildings are built. Being aware of the problem is the first step in resolving it. This awareness has helped reduce deaths from indoor air pollution. Explore the graph below to see how deaths have decreased. As expected, developed countries have been able to reduce their already lower deaths more than developing countries.

AP Exam Tip

Indoor air pollution is less well-known, but possibly more important because people spend so much time indoors.

 

[CC BY-NC-SA 4.0 Links to an external site.] UNLESS OTHERWISE NOTED | IMAGES: LICENSED AND USED ACCORDING TO TERMS OF SUBSCRIPTION - INTENDED ONLY FOR USE WITHIN LESSON.