Air PollutionPollution

How Does Humidity Affect Air Pollution?

Since air pollution is getting worse, it’s important to know how environmental factors like humidity (high and low) affect the number of pollutants in the air. Throughout this article, we will cover how humidity affects air pollution and quality, as well as how we can control it.


What is Humidity?

The amount of water vapor in the atmosphere is called humidity. Water vapor is constantly being released into the air and condensing back into liquid form under most atmospheric conditions. This process, known as evaporation and condensation, is not visible to the naked eye but is constantly happening around us. Let us learn about how this constant process is affecting air pollution.

Factors Influencing Humidity

Before we dive deep into how humidity affects air pollution, we must understand the factors that affect the humidity in the first place because it will directly link to air pollution.

  • Wind speed and Direction: The more the wind speed, the more pollutants and particles will be dispersed, lowering air pollution levels. Low wind speeds, on the other hand, cause pollutants to stay in an area for longer, causing more air pollution.
  • Temperature: The temperature can also affect humidity and air pollution. When it’s hot outside, the air holds more water vapor. During humid summers, the air is sticky and full of moisture, making it difficult to stay cool. In contrast, our bodies lose moisture more quickly in cold weather, which is why we should stay hydrated.
  • Pollutant Types: Pollutant properties and type play a role too since some pollutants are more affected by humidity than others.
  • Level Of Precipitation: Humidity levels are also affected by precipitation levels. More precipitation tends to raise humidity levels.

Weather and season can also affect humidity, and the amount of humidity varies from place to place.

Also Read: Different Types of Seasons with Months.

How does Humidity Affect Air Pollution?

As we have understood the factors mentioned above, we can now make a connection between them and pollution. Humidity can affect air pollution in several ways, including the dispersion of pollutants, reactions between chemicals, movement of pollutants, impacting visibility, precipitation, etc. Let’s look at them in detail:

Dispersion Of Pollutants

Humidity can affect pollution dispersion. If humidity is high, pollutants can stick to water droplets and other particles in the air, causing them to be removed from the atmosphere. In turn, this reduces pollutant concentrations and improves air quality. But it can also cause pollution to accumulate on surfaces, which can harm the environment.

Reactions Between Chemicals

Humidity can speed up the chemical reactions that produce air pollutants, like ozone and particulate matter. Basically, water molecules can react with pollutants and other chemicals in the air to create new compounds. In the presence of sunlight, nitrogen oxides and volatile organic compounds may react to form ground-level ozone, which is harmful to the environment. Mind you, here too, temperature (factor) plays a part in the chemical process.

Pollutants Movement

Humidity can affect the flow of air pollutants over long distances. Since water molecules attach to air particles and make them heavier, they’re more likely to settle down. In different regions, this can have both positive and negative consequences for air quality. Remember, here another discussed factor i.e., wind speed and direction play a major role in the transport of the pollutant.

Affecting Visibility

When humidity levels are high, fog and haze can form and contribute to air pollution. Urban areas that have high levels of particulate matter can be especially vulnerable to this problem. Also, the pollutant type and properties play a role here.

Also Read: Smoke Pollution: Causes, Effects and Prevention.

Precipitation: Acid Rain

Humidity also plays a role in precipitation formation, which affects air pollution. High humidity levels can help clouds to form and precipitation to fall, which removes pollutants from the air. But when the precipitation is acidic, it can cause other problems, like acid rain. Temperature and wind in general also affect precipitation.

Effects Of Humidity on Human Health

We normally cool down by sweating and using the ambient air to get rid of sweat formed on our skin. However, high humidity causes warm moisture to remain on our skin longer as more water vapor can’t get into the atmosphere, making us feel even hotter. This is known as the heat index by meteorologists. Overall, hot weather affects our physical comfort due to humid temperatures.

But we just learned that humidity also affects air pollution and obviously, any kind of pollution is hazardous to human health. Air pollution, specifically, has serious health consequences, with one-third of deaths from stroke, heart disease, and lung cancer being attributed to it. The effects of air pollution on health are similar to those of smoking tobacco and are more significant than the effects of consuming too much salt.

Air pollution affects us directly and indirectly. Air pollution and climate change are closely connected. This is because the burning of fossil fuels, which is a leading cause of climate change, is also a major contributor to air pollution. Therefore, addressing one issue can also help with another.

There are two types of air pollution: indoor and outdoor. Both of these pollution types could be affected by humidity as we saw above. Now let’s look at the ways to control humidity.

Also Read: What Are the Sources of Indoor Air Pollution?

Strategies for Humidity Control

Various research has shown that indoor humidity levels that are either too high or too low can have adverse effects on health. Low humidity can lead to dry air, which can cause dry skin, chapped lips, and sore throats. It can also make indoor spaces feel colder than they are.

On the other hand, high humidity allows for proliferation; that is the multiplication of pathogens such as mold, fungus, dust mites, and bacteria, as it creates an environment with too much moisture. And hence, homes with high humidity often have elevated levels of air pathogens like mold, which can lead to serious health problems like asthma, allergic reactions, and respiratory infections. These pathogens generally tend to thrive in homes and buildings with relative humidity levels above 70%.

Due to these various reasons, we should keep the humidity levels of our homes in control. One can reduce indoor humidity by:

  • Air conditioners and dehumidifiers help remove excess moisture.
  • Make sure wet clothes and towels don’t get near the stuff you want to keep dry.
  • Make sure bathrooms are ventilated with exhaust fans.
  • You should open the windows whenever you can to let fresh, dry air circulate in your home.
  • Regularly check your home for water leaks that can raise humidity levels.
  • If you have cracks or openings in your windows, doors, or other parts of your house, seal them up.
  • For extra moisture prevention, you can also cover the bare flooring with carpets or rugs.

It should be noted that extremely high or low humidity is dangerous and there should be a balance between the two.

Also Read: How Does Air Pollution Affect the Animals?


We learned that humidity, or the concentration of water vapor in the air, along with other factors like temperature and wind, plays a big role in air pollution levels. Humidity unavoidably promotes air pollution by contributing to the formation and persistence of pollutants and also dispersing and transporting them.

This change might seem small, but it constantly affects the environment in a way that shouldn’t be overlooked. The problem of air pollution is exponentially growing, and it can have serious negative effects on human health including cardiovascular and respiratory issues. It can also cause serious problems for our ecosystems on earth. Therefore, individuals, communities, and governments need to protect air quality. It’ll help reduce air pollution’s negative effects on public health and the environment.

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