Indoor air quality is often measured when occupants report health symptoms or problems with ventilation. Many pollutants can be monitored, but testing for most is expensive.
The upper part of the respiratory system contains membranes that trap dirt, dust, and viruses before they enter the lungs. When humidity is too low, these membranes lose their moisture and become less effective.
Cold Weather
People tend to stay inside with the cold weather bringing snow and ice. This means that normal pollutant sources like mold, dust, and volatile organic compounds (VOCs) may continue to affect indoor air quality. Moreover, with schools closed and people trading ventilation systems for heating, these pollutants are trapped inside homes and workplaces. Poor winter indoor air quality can aggravate existing respiratory conditions and even cause other health issues like dry skin and itchy eyes.
The low humidity levels of the season can also be problematic. This is because the human body is made up of 60% water vapor, and as it dries, our mucous membranes can become inflamed. It can even result in the development of a painful sore throat. This dry air can also exasperate sinus, allergy, and asthma symptoms.
In addition, as the temperatures drop, many people rely on fireplaces and wood-burning heaters to stay warm. As a result, the level of carbon monoxide and wood smoke in the home increases significantly.
Another reason winter is a bad time for air quality is that atmospheric conditions can lead to temperature inversions. This is a phenomenon where a layer of warm air sits below a layer of cooler air, forcing the pollutants downward and into the home.
The cold winter air is also denser, which makes it harder for the pollutants to disperse. This can lead to higher concentrations of ground-level ozone, nitrogen dioxide, and particulate matter. It can also make it more difficult for the natural air movement that normally takes pollutants away from homes and exacerbates the effect of indoor VOCs like formaldehyde. These VOCs are released from household products such as furniture, carpeting, and paints. In addition, they can come from dry-cleaned clothes or drapes, as well as some household cleaning products. VOCs can also be off-gassed from particle board and plywood paneling. This is why it’s important to be vigilant in preventing poor indoor air quality all year round.
Extreme Heat
Increasing air temperatures cause heat waves, which can be dangerous both outdoors and indoors. When heat and air pollution are combined, the health risks are even more serious. The combination of heat and air pollutants increases the amount of harmful chemicals in the air, which can increase a person’s risk of respiratory illness, heart disease, and other conditions. In addition, high levels of particulate air pollution can trigger asthma and other respiratory conditions. Wildfires can also add to the problem by releasing carbon monoxide, polycyclic aromatic hydrocarbons, and other toxic air pollutants into the atmosphere that combine with extreme heat to create ground-level ozone.
Air pollutants from inside homes, such as cigarette smoke, household chemicals, building materials, and pesticides, may also contribute to poor indoor air quality during heat waves. People spending more time indoors, such as young children, older adults, and those with chronic health conditions, are at greater risk from the combined effects of extreme heat and indoor pollutants.
Outdoor air pollutants can also affect indoor air quality during heat waves, especially when people open windows and doors to cool their homes. This allows more of the outdoor pollutants to enter the home, causing an increase in indoor concentrations. Fortunately, sources of indoor pollution can usually be eliminated or reduced by using fewer toxic products and improving ventilation.
During a heatwave, the risk of death due to exposure to both extreme heat and air pollution is much higher than either one alone. A study by the University of Southern California found that a person’s chance of dying on days with high temperatures and air pollution is 21% higher than on days without extreme conditions. However, the good news is that climate change will likely reduce the number of days with both extreme heat and air pollution, reducing the impact on human health. Airthings smart air quality monitors provide real-time information about the levels of indoor air pollutants, including particulate matter and airborne chemicals, so you can take action to protect your health. This data can help you plan ahead and prepare your home for the coming summer weather.
Indoor Habits
Many factors affect indoor air quality, including occupant behavior, outdoor climate and weather conditions, building materials and construction/renovation techniques, indoor/outdoor sources of pollutants, and occupant activities. Some indoor air pollutants are associated with health effects such as odors, irritation of the eyes, nose, and throat, headaches, fatigue, and respiratory infections. Some have been shown to lead to more serious health problems like heart disease, stroke, and cancer.
The rate at which fresh outdoor air enters a building is also important. This is particularly true during winter when the cold temperatures and low winds can limit natural ventilation. Indoor air pollutants can include volatile chemicals such as cleaning products and scented candles, biological contaminants (mold, viruses, and allergens) from smoking, pets, food preparation, and household and office maintenance, and chemical off-gasses from building and furniture materials.
Human activities produce most indoor pollutants, but some originate from outdoor sources. For example, radon, a radioactive gas that forms from the decay of uranium in soils, can enter homes and other buildings through cracks and gaps. Other outdoor pollutants such as secondhand smoke, volatile organic compounds from pesticides, and carbon monoxide can also enter homes and other buildings.
Building occupants can contribute to poor indoor air quality by not opening windows or using exhaust fans and by smoking indoors. They can also inadvertently bring soil and dust into buildings on their shoes, clothing, or pets, along with pollutants that adhere to these particles. Occupants may also be exposed to harmful gases such as radon and volatile chemicals from solvents, paints, and adhesives.
The best way to improve indoor air quality is through healthy home and office habits coupled with whole-home IAQ control solutions such as ventilation, filtration, and humidification. It is also important to make sure that all water-related issues are addressed promptly. For example, leaks can increase humidity levels and lead to mold growth, and excessive moisture can cause wood structures to rot or degrade. Occupants should also consider adding air-purifying plants such as spider lilies and peace lilies to their indoor spaces.
Humidifiers
The humidity level of indoor air varies depending on the season and outdoor conditions. It is typically highest in summer when outdoor temperatures are warmer. In winter, the average home’s humidity falls to about 25 percent due to cold temperatures and forced-air heating systems that move the air around quickly, speeding up evaporation. Humidifiers can help to restore proper moisture levels.
Dry conditions cause discomfort for many people. These include dry skin; chapped lips; itchy eyes, especially if you wear contact lenses; and congestion. Increasing your house’s humidity helps relieve these symptoms and improves your overall comfort. Humidifiers can also benefit those with asthma or other respiratory issues by alleviating their symptoms.
Swamp coolers in garages and other shared areas of the home are good for everyone living there, but humidifiers can be used in individual bedrooms and are generally easier to use. There are two main types: ultrasonic and evaporative humidifiers. Ultrasonic humidifiers use small vibrating particles to add water vapor to the air, whereas evaporative humidifiers evaporate water, creating moisture in the process. Both have their own benefits and drawbacks. A professional can recommend the best type of humidifier for your home.
Using a humidifier is important for the health of your family. It can help you avoid problems caused by extreme air dryness, such as itchy or flaky skin; cracked woodwork and window sills; peeling paint; a musty odor; and static electricity. It can also help alleviate some upper respiratory issues, such as a persistent cough or sore throat, sinus congestion, and mucous membrane irritation.
When choosing a humidifier, be sure to consider the quality of the water used in it. Using tap water with a high concentration of minerals will create mineral particulates that can be inhaled, which can cause serious damage to the respiratory system. An experiment conducted by IQAir showed that using distilled water in a humidifier reduced the number of fine dust particles released into the air by 13 times.
If you suspect that the air in your home is too dry, a simple hygrometer can tell you for sure. A hygrometer is an inexpensive device that measures the moisture content of the air. You can buy one at most home improvement stores or get a professional to assess air quality and make recommendations.