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How Do Seasonal Changes Affect Indoor Air Quality

Indoor air quality (IAQ) is vital to provide a safe and healthy working environment. However, while proper ventilation and housekeeping can mitigate some of the IAQ issues you experience, they will not cover unexpected changes that occur throughout the year. These changes, such as passing seasons and the age and health of your building’s occupants, are not as easy to control. When you know what to expect during each season, you can improve the air quality for the majority of those in your building.

What are the short term effects of poor indoor air quality?

Short term effects of poor indoor air quality can include:

  • Headaches
  • Fatigue
  • Dizziness
  • Eye redness
  • Nose irritation
  • Throat soreness

Over time, constant exposure to poor air inside can lead to cancer, heart disease or respiratory diseases.

What are the potential sources of poor indoor air quality?

There are many sources of indoor air problems, but the most common include:

  • Outdoor air
  • Tobacco smoke
  • Building materials
  • Mold
  • Cleaning products
  • Ventilation systems
  • Fuel-burning appliances

Among these, outdoor air and excessive moisture tie closely to seasonal variations. Since seasonal variables depend on location, our focus is on our local operations in Pennsylvania. In this guide, we’ll discuss how the seasons affect symptoms felt by those inside your building and how you can keep air quality at a healthy level.

Indoor Air Quality Changes During the Spring

In March, April and May, temperatures and humidity levels rise. These bring accompanying pollen, dust and mold inside through open windows and doors. Symptoms correspondingly increase, whether individuals expose themselves to these outdoor allergens at work, home or during their commutes.

Though allergies may increase, colds, cases of flu and other respiratory infections tend to decrease due to the extra moisture in the air. While dry air in the winter encourages the spreading of upper respiratory infections, the higher humidity of spring decreases these illnesses.

Tips to Improve Indoor Air Quality During the Spring

When bugs start to appear inside during the spring, choose non-chemical means of keeping them out as much as possible. Close up any gaps in the building and encourage occupants to clean up kitchen areas and avoid leaving out any food. Taking these steps will prevent a buildup of chemicals that some find irritating.

If you have construction or deep cleaning projects occurring in your building, schedule it during times occupation will be at a minimum. Keeping workers out during renovation or cleaning projects reduces their exposure to dust and pollutants produced from these processes. Ensure those engaged in these types of projects remove all debris or garbage before leaving.

To prevent pollen and dust from getting into the ventilation system, schedule regular housekeeping. The main cause of an accumulation of dirt in ventilation systems is a poor quality of cleaning. When temperatures warm enough in the late spring to warrant using the air conditioner, clean off any dust buildup on the coils to ensure the system works well and air quality stays good.

Air Quality Changes Indoors During the Summer

During June, July and August, temperatures increase to their highest levels of the year. Pollen levels drop as flowers produced during the spring begin to turn into fruit or make seeds after pollinating. Mold, dust and humidity also increase with the temperatures, though.

The rising mold and dust levels will also affect those inside the building, especially if you have not had your ventilation system cleaned. Air conditioners can blow dust inside the air ducts throughout the building, irritating those with a sensitivity to dust. The lower humidity inside from an air-conditioned environment compared to outdoor levels can affect those with sinus problems.

Running the air conditioner too often raises electricity bills during the summer. You may try to offset this by integrating more outdoor air into the air conditioner’s intake. Using too much air from outside, however, introduces mold and dust into the indoor air. Finding a balance between outdoor air intake, indoor air quality and electricity costs is one concern for building operators during the summer.

Tips for Improving Summer Indoor Air Quality

When using the air conditioner in the summer, the indoor air can dry out. Too much moisture can contribute to mold growth. Monitor indoor humidity and adjust the air conditioner to keep levels between 30 and 60 percent for the greatest comfort and best air quality.

Additionally, since you will likely use the air conditioner more often during the summer, plan on monthly checks of the system to ensure it does not distribute dust and mold through the building. Before starting the system, have the ducts cleaned out, and the system checked to get the most efficiency and cleanest operation.

Indoor Air Quality During the Fall Season

Extra moisture in the air and vegetation decay lead to the year’s highest levels of outdoor mold. Though mold levels increase in September, October and November, elevated levels may persist through December, depending on weather conditions.

Additionally, some plants will produce pollen during the fall. Those with fall allergies may have reactions to these pollens, depending on the temperature, wind and moisture levels.

Tips to Improve Air Quality Inside During the Fall

While you must pay attention to possible sources of excessive humidity to prevent mold growth throughout the year, autumn poses new concerns. Indoor air quality in fall seasons has a higher likelihood of mold problems due to decaying vegetation. You must ensure your building has proper ventilation to reduce the humidity that encourages indoor mold growth.

Stop any leaks as soon as they happen and ensure bathrooms and other moist environments have adequate ventilation. Repair leaky roofs as soon as possible and remove any walls, ceilings or carpeting materials that sustained water damage from the leak. Leaving these in place encourages mold growth where you cannot see it. It can still affect air quality, though, even hidden behind paint or inside walls.

Changes in Air Quality Indoors During the Winter

In the winter, freezing temperatures prevent the growth of mold spores. Humidity levels plunge to their lowest levels outside and inside. Heating systems inside keep the air even drier than outdoors, which could dry out mucous membranes and cause irritation in the eyes and nose. Respiratory infections spread easily in such dry weather.

In the winter, bringing in outdoor air may reduce heating costs, but too much could cause freezing of ventilation system coils. However, using more humid outdoor air for the heating system’s intake can help improve humidity levels inside. As in the summer, building managers must find a balance between operating their heating systems at a comfortable interior temperature without bringing too many outdoor pollutants inside.

How to Improve Air Quality Inside in the Winter

Just as you should monitor your indoor humidity during the summer, you should do the same in the winter. If your building regularly drops below 30 percent humidity, consider installing a humidifier to add moisture back into the air for comfort and to reduce the spread of upper respiratory infections. When using humidifiers in the winter, check them weekly to ensure they do not have mold growing in them. Clean and disinfect the humidifiers as recommended to ensure they do not contribute negatively to your indoor air quality.

Get professional help to balance outdoor air flowing into your building’s HVAC system and the air quality inside. Taking measurements of temperature and humidity can ensure you have reached a good balance of both.

Partner With TRC for Better Indoor Air Quality All Year Long

Of course, these tips only encompass a few of the things you can do to improve all aspects of indoor environmental quality. Having a plan helps, but you may need assistance in making that plan and implementing it. That’s where we can help.

Though you cannot stop the seasons from changing, you can reduce their impact on the air quality inside your building by making your building’s indoor air quality as high as possible. Though the age and health of building occupants determine their reactions to indoor air pollution, improving the air inside can keep everyone healthier throughout the year.

Looking for effective solutions to your problems?

Turn to the experts at TRC.

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