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How Does Relative Humidity Affect Indoor Air Quality?

How Does Relative Humidity Affect Indoor Air Quality?

Water is essential for life, but it also has a darker side. When water wants to flex its might, it can carve out canyons and destroy property. When it comes to assessing the water supply on earth, most of it is in either a solid or liquid state. Around 0.001% of all the water on earth exists in a gaseous state as water vapor.

However, while that might seems like a small slice of the water on earth, it equates to billions of gallons sloshing around in the atmosphere at any given moment. Humidity is a measurement of the water vapor concentration in the air.

Humidity levels vary depending on your location on the planet. If you live in a coastal region close to the equator, humidity levels can rise to over 25% in tropical areas. The humidity impacts our quality of life. Anyone stuck at the coast on a hot day when the humidity is high is having a rough time.

Your clothes get wet and stick to your skin, and it feels like you're in a sauna. Humidity also causes issues with air quality in the home when it gets too high. High humidity can lead to the onset of mold development in rooms, resulting in health consequences for the family.

To keep things under control, homeowners have to understand the specifics around relative humidity (RH) and how it affects air quality. This post unpacks everything you need to know about how relative humidity affects indoor air quality.


How Do We Measure Relative Humidity?

Relative Humidity is a reading of the current humidity levels in the air. However, it's important to note that while an RH reading expresses as a percentage, it doesn't actually refer to the percentage of water in the air.

The reason for this is due to the air containing different quantities of water due to the ambient temperature of the air. The physics behind understanding might be a bit much to get into for this article.

However, for a simple understanding of the subject, think of it as hot air holds more water vapor than cooler air. At RH levels of 68%, a cubic meter of air has 18-grams of water.

At 77%, it holds 22-grams or 22% more. With a cubic foot of air holding 22-grams of water, the relative humidity is 100%.

As temperatures increase, the relative humidity levels decline by the same amount of water vapor, and vice versa with decreasing temperatures.

So, we can conclude that relative humidity is useful for use as a scale of measurement. At 0% RH levels, there is no water in the air. At 100% RH, the air is as humid as it can get without it raining. At 100% RH, the moisture in the air will condensate on surfaces.

Cold rooms hold less water than warmer rooms. Therefore, a 90% RH in a cold room holds more water than a 90% RH in a warm room.

As a result, people in tropical climates swear they can "feel the climate." Since humidity is high and temperatures are up, there is much more water in the air than in cold climates at high elevations.

So, what does all this mean? What are the optimal living conditions for RH in my home? According to the experts, it's best to have air conditions in your home measuring between 30% to 55% RH. It's easy to control the RH through the dehumidifier function on the machine if you have an air conditioning system or HVAC.


Relative Humidity Indoors and Your Lifestyle

Relative humidity affects the comfort we experience in our home and our lifestyle. Living in 100% RH conditions at the beach is a nightmare. You can't own electronics because the air corrodes everything, and on really hot days, it feels like your sitting in a swimming pool in your lounge as you sweat in your clothes.

According to reports from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), comfort is a combination of temperature, RH, airflow, metabolism, and clothing. The organization has a calculator to figure out how these factors play a role in their interaction with your indoor living experience.

However, simply put, lower RH at higher temperatures is the preferable comfort zone for any living environment. The RH can really make things uncomfortable if it gets high in warm climates. Trying to fall asleep when soaked in sweat is not a pleasing experience.

When sleeping, the body can't regulate its temperature as well in high RH environments. As a result, you get poor quality sleep, and you might wake up feeling too cold or too hot at times during the night.

The RH in your home also creates problems with the living space when it gets too high. Humid homes invite the spread of dust mites. These critters live in your couch cushions, carpets, and mattress, and they suck water out of the air. In high RH environments, the pests thrive, and you might notice an increase in dust allergies as they expand colonies in your home.

Humid conditions also create problems with mold in the home. Mold loves growing in dark, damp spaces. It spreads quickly after establishing, creating respiratory problems in people living inside the residence.

Typically, dust mites throve in humid conditions over 55% RH, and mold prefers an RH of 80% to spread around the home. To stop dust mites and mold, keep the RH in your home at 50%.

However, it's important to note that a low RH can also cause health issues if the air gets too dry. Low humidity in the air results in dry and itchy skin and the onset of upper-respiratory infections. The low levels of water vapor in the air dry out the lungs, making you at risk of contracting diseases.


Humidity, Mold, and Your Health

The biggest threat presented by overly high relative humidity in the home is mold growth. Mold is a pathogen that spreads fast in the right conditions, and it loves dark, warm, humid areas. During the summertime, mold spores spread through the air outside.

The spores may wander into your home, resulting in infestations occurring in areas like the laundry room, basement, and garage. As the mold spreads, it starts releasing spores into the air. Some mold varieties, like the dreaded black mold, carry mycotoxins that interact with the body.

Breathing in black mold spores creates a host of health issues involving the respiratory and nervous systems and the brain and other organs. Affected individuals could end up in the emergency room in need of medical assistance after overexposure to the pathogen.

In many cases, it's hard to detect the presence of mold in the air, especially in humid locations. You can't see the spores floating in the air column, and the damp conditions may mask the musty smell produced by the mold.

So, how do you know if there is mold contamination in your home?


Use a Professional Air Quality Testing Service

MI&T is a professional mold detection service. We use the latest technology to measure the air quality in your home and identify the presence of mold spores. We'll find the mold, wherever it is, even if it's in the walls.

While we test the air and give you a comprehensive report on the air quality, we're not a removal service. However, we can provide you with advice to help you remove the mold yourself. If it's a larger infestation of 10-square feet or more, we'll recommend you use a removal company for the task.

If you are clearing the area yourself, make sure to use the right materials and the correct procedure for clearing the infestation. Failing to remove the mold or clean it effectively results in it coming back.

As an unbiased third-party company, we don't contract mold removal services to take the bias out of your inspection. Contact us for an immediate assessment of the air quality in your home. We'll arrive at your property with everything we need to conduct the exam, and we finish fast.


Does a Dehumidifier Help Control Relative Humidity?

If you live in a country or region with high RH levels, you'll need to control the humidity in the room. As mentioned, high humidity levels cause problems with mold growth and pest infestations. A dehumidifier extracts moisture from the air, returning dry air to the living space at the correct relative humidity.

Typically, dehumidifiers come with a tank that fills with water as it pulls it out of the air in the room. You can set your preferred RH on the device, and it gets to work in removing the moisture from the air. However, you'll need to ensure the RH doesn't get too low with the dehumidifier.

Some homeowners may find that their indoor plants are the cause of high relative humidity levels in the home. If that's the case, move them outdoors. The moist soil combined with high temperatures in the room increases the humidity in the air.