How Urban Living Intensifies Allergy Symptoms: Exploring the “Heat Island” Effect

City life offers so much to do and see with lush greens, a bounty of restaurants and shops, museums, theaters, and so much more. In Fresno alone, there are around 4,600 retail food facilities, which include restaurants, markets, bakeries, and food trucks, and 193 parks. With all those green spaces and businesses offering a chance to relax in the sun or become active in the great outdoors, you can’t imagine there could be a downside.

Urban living does have its downsides, however. One of them is known as a “heat island” effect. It’s a problem for anyone suffering from allergies. Your allergies may seem out of control and unbearable, but there are ways to manage the symptoms for lasting relief with advice from our team at Premium Allergy.

What Is a Heat Island?

What exactly is a heat island? Cities are large, crowded areas with many industries, businesses, apartment or condo buildings, and continual construction projects. The temperature in that area is warmer than in outlying towns and suburban areas for several reasons.

• A higher number of HVAC systems release heat outside.
• The sun heats the buildings, roads, and sidewalks, and that heat is released back into the environment. 
• Heat is produced by cars, trains, buses, etc. 
• People who reside or work in the city also give off some heat.
• Construction equipment and power tools generate heat.
• Businesses like restaurants or manufacturers also release heat.

In addition to the heat, the traffic and systems mentioned above also release higher numbers of greenhouse gases in many situations. That adds to the problem with poor air quality, which impacts allergies.

The Challenges You Face When It Comes to Your Allergies and Urban Living

The heat island effect impacts how allergy season plays out. You might think that the crowded neighborhoods and reduced green space would make it better for allergy sufferers, but the opposite happens.

1. Air Pollution Impacts Pollen and Allergy Severity

Exhaust fumes from vehicles, public transportation, city industries, and construction sites are released into the air every day. That particulate matter aids in the release of pollen by altering how plants grow. PM can increase the amount of pollen that’s released and the ability of that pollen to trigger allergies.

1. Pollen Counts Often Increase

Because air circulation is limited in a congested city, pollen counts build up. It’s harder for the wind to blow pollen away, so it becomes trapped at ground level. Plus, trees chosen to line city streets are often heavy pollen producers. 

Chinese pistache is one of the trees you spot lining Fresno streets, and this tree sheds a lot of pollen in the spring. Crepe myrtle pollen is very heavy, so it’s not one of the most common allergens, but it does affect some people. You’ll also find pollen-heavy trees like weeping bottlebrush, emerald sunshine elm, and many others that release pollen into the air, especially in the spring.

1. An Abundance of Dust Mites and Mold

Cities often have older buildings. If those buildings have inadequate HVAC systems. If humidity levels are higher than they should be, dust mites and mold will thrive. Plus, apartment or condo buildings have shared ventilation, which helps spread those allergens.

Fresno was founded in 1872 by the Central Pacific Railroad Company. Within 18 years, the city’s population topped 10,000 with many Victorian buildings lining the streets. With more than 300 designated historic buildings and four historic districts (Chandler Field, Huntington Boulevard, Porter Tract, and Wilson Island), there are a lot of older buildings housing residents and businesses.

Fresno is the Perfect Setting for Allergies

When it comes to an urban heat island effect, Fresno is a great example of why allergies can get so frustratingly annoying. 

1. The Climate

Fresno has hot, dry summers. The sun shines approximately 83% of the year. That sunny weather warms pavement and buildings, which increases the ambient air temperature. Plus, wildfires are an issue in many outlying regions, which increases the risk of smoke and particulate matter that fills the sky while fires burn.

Average monthly temperatures in Fresno tend to be very hot from May to October. It’s common to see lows in the mid-60s at night and days nearing 100 from June to September. It’s cooler in the mountains, but both areas get little rain from May to October.

1. The Location

Fresno is in the San Joaquin Valley. This basin traps air and pollutants, which worsens the effects of being in a heat island.

1. The Surrounding Agricultural Lands

Areas surrounding Fresno tend to be agricultural, with many vineyards located outside the city. That alone brings in pollen from the growing crops. 

Fresno County is known as the “Raisin Capital of the World,” with more than a dozen wineries, including two commercial ones. The county has 1.88 million acres of farmland where almonds, cotton, grapes, peaches/nectarines, pistachios, and tomatoes are grown.

1. The Lack of Green Space

Fresno is trying to do more to combat the effects of being a heat island, but it’s a work in progress. There isn’t a lot of green space to help balance the effects of urban living, so heat from the building and pavement is a problem.

Woodward Park is the largest park in Fresno, covering 300 acres with trails, playgrounds, a Japanese garden, and a dog park. Fresno itself covers 115 square miles, which is about 73,600 acres. If you consider the size of the city versus the size of the largest park, green space is greatly outnumbered.

What Can You Do to Lessen Your Allergies in a Heat Island Setting?

You cannot eliminate all allergens, but you can lessen your allergy symptoms and bodily responses to allergens. There are several ways to do this.

• Shower after spending time outside.
• Wash your clothing immediately after you come in.
• Avoid outside activities during peak pollen seasons and times of day.
• Run an air purifier indoors and keep windows closed.
• Change your HVAC system’s air filter regularly.
• Check your yard for common allergens and replace plants that trigger severe allergies if necessary.
• Work with an allergist to develop a personalized treatment plan, such as immunotherapy treatments like allergy shots or sublingual allergy treatments.
• Make sure your home doesn’t get too humid, which encourages dust mites and mold. Dust mites don’t thrive if the humidity level is below 55%.

Resolve Severe Allergy Symptoms and Enjoy Urban Living

Life in Fresno doesn’t have to mean you must lock yourself indoors and avoid spending time outside in Fresno’s bustling culture and natural environments. Premium Allergy & Respiratory Center offers lasting solutions for relief from allergy symptoms. Make an appointment with our allergist and embrace urban living without the challenges allergies create.