The dog days of summer are upon us, and many of us are sweltering in the heat. If you live in a big city, you may feel worse than your country cousin due to the “urban heat island effect”. In an urban heat island, temperatures may be 6-8ºF warmer than surrounding rural areas, fields, or woodlands.  Urban heat islands are caused by a combination of factors:

  • Loss of vegetation that shades buildings and cools the air through evapotranspiration
  • Hard surfaces (buildings, streets, and parking lots) that absorb solar radiation and radiate it back to the air/atmosphere
  • Waste heat from electrical use, water heating, car & truck exhaust, and other thermal and mechanical sources

The temperature differentials are worse at night, when hard surfaces like asphalt pavement, brick, and concrete radiate the heat they absorbed during the day back into the air. Calm air also makes it worse.

The urban heat island effect causes a number of problems. It exacerbates normal summer discomfort for everyone—causing people to crank up the air conditioner (and yes, generate more waste heat), and it makes elderly or sick people more susceptible to problems brought on by heat waves. It’s tough, and sometimes dangerous, for athletes and for those who work outdoors–such as construction workers, roofers, police officers and highway workers. Higher temperatures also increase smog formation, which boosts health risks to the elderly, children, asthmatics, allergy sufferers, and those with respiratory problems. Finally, stormwater runoff from paved urban areas causes excess warming in creeks and lakes, which can damage ecology in those environments.

There are a number of green building materials and practices that urban individuals and organizations can use to mitigate or reduce the heat island effect:

Plant trees. In summer, they create shade which reduces air conditioning loads on a building, and in winter, they shield buildings from wind and unwanted heat loss. They also produce oxygen, and create bird & animal habitat.

Green roof with walking path

Install green roofs and walls. These are vegetated, carefully engineered surfaces that support plant life, and keep the building cool. They provide other benefits, too, including improved drainage (protects underlying roof and reduces stormwater runoff), recreation for employees or occupants, and even herb or vegetable growth. Green roofs also improve air quality because plants convert carbon dioxide to oxygen, and filter out other contaminants. Although green roofs may cost $10-$15/sf more than traditional roofs, these costs are offset by energy savings, longer roof life and reduced maintenance costs, and by various grants and tax incentives.

GAF green roof system, showing drainage mat & moisture barrier

Green Roofs have enjoyed increasing popularity in Europe over the last decade, with government incentives stimulating a multi-million dollar industry.  North American planners, builders and consumers are also beginning to consider green roofs for malls, schools, hospitals, and homes. In New York State, green roofs have been installed at the Bronx Zoo, Cornell University, Pace University, the Bronx County Courthouse, and at Rockefeller Center Roof Gardens.

White roof coated with Bulldog Durex.

Install a white roof to increase reflectivity (albedo), so that solar radiation is not absorbed by your roof to be re-radiated later. For flat roofs, Green Depot recommends Bulldog Durex Elastomeric White Roof Coating.  It’s a flexible, mildew- and UV-resistant waterborne roofing topcoat made with 100% acrylic resins. It reflects heat from the roof surface: lowering cooling costs, and extending the life of roof membranes and surfaces. It can be used over a variety of existing roof surfaces, including metal, asphalt, masonry, and EPDM.

To learn more, visit Lawrence Berkeley Laboratory’s Urban Heat Island site, or the independent site Urban Heat Islands, or the US EPA’s site on the Heat Island Effect.

In a previous post, I talked about how allergy sufferers can get some relief by using green products including air purifiers in the home. Today, I’d like to talk about diagnosis and prevention. Sure, it’s great to have more access than ever to over-the-counter and prescription medications to control allergy symptoms (the inventors of Zyrtec are my heroes), but it’s also important to learn exactly what allergens you’re most at risk from so you can avoid or treat them.

One way to do this is to visit an allergist, who may conduct scratch tests to determine what your allergenic or asthmagenic triggers are, and lung function tests to establish a baseline for your pulmonary heath. Allergists can customize a desensitization injection regimen to directly attack the things you’re allergic to: different types of plant and tree pollen, animal dander, etc., and they keep an extremely close watch over your dosing frequency and levels. They can also advise you on what materials or places to avoid, or how to allergy-proof your house. For example, if you’re very allergic to dust, they might suggest that you limit the amount of carpeting or curtains in your house, as these attract and retain dust, or that you purchase hypoallergenic linens and bedding.  The American Academy of Allergy Asthma and Immunology can help you find a board-certified allergist. Your health insurance company or primary care doc can provide referrals, too.

Another way to get a handle on your risk is to test your house for common allergens. The Family Air Care  Indoor Allergens and Mold Test Kit tests for 5 common triggers of asthma and allergies:

Family Air Care test kit

Family Air Care® Indoor Allergens and Mold Test Kit

  • Cat allergen (carried indoors on clothing, it can be present even in homes without cats)
  • Dog allergen (also carried on clothing, although to a lesser extent)
  • Dust mite allergen
  • Cockroach allergen
  • 13 species of mold—evaluated using EPA’s American Relative Moldiness Index

The kit was developed by National Jewish Health in Colorado—the nation’s leading respiratory hospital—and retails for $299.

Since we spend 90% or more of our the time indoors, it pays to determine which allergens bug us most so we can try to eradicate or control them. The FAC test kit is easy to use: you just attach a small filter to your vaccum to collect a sample, mail it in, and view your house’s results on-line using a private access code.

The results will tell you whether the levels of the 5 types of allergen above are high, medium, or low in your house. Then you can decide what type of green products to buy to control them. I’ll discuss these in subsequent posts. For now, I just want to emphasize that getting your body and your home tested is a diagnostic combination that packs a punch.

If you’re like me, the dog days of summer usually find you toting around a box of tissues, clinging to your Allegra or Zyrtec bottle like a security blanket, and blushing each time you sneeze loudly in a public place. There are so many allergens we’re routinely exposed to—dust, pet dander (on our friends’ clothing—even if not in our own houses), tobacco smoke, cleaning chemicals, molds, and a host of flower and tree pollens.

Quick: before the ragweed blooms

When I was a kid, my mom uttered the word “ragweed” like it was a swear. There was venom in her voice directed at this feathery plant who made her kid wheeze and sneeze uncontrollably. Turns out I have a lot of company. According to the Asthma and Allergy Foundation of America, 30 to 60 million Americans suffer from ragweed allergies—many miss school and work due to their discomfort, and many have trouble sleeping. The ubiquitous plants bloom from mid-August through October, each one releasing around a billion potent pollen grains, making us miserable in what can seem like a billion different ways. Itchy throat. Watery eyes. Coughing. Sneezing. Sniffling. Aggravated asthma.

Thankfully, there are a host of green products and practices that can bring us relief. Top among them is closing the windows, and cleaning your indoor air with an

Austin Air HealthMate Jr. Alen Paralda air purifier air filter

Healthmate Jr, and Alen Paralda

air purifier.  We really like Austin Air’s HealthMate Jr. that uses 6.5 pounds of activated carbon and over 30 square feet of medical-grade HEPA to filter 125 cubic feet of air per minute. It will remove chemicals odors, pollen, dust, mold spores, and other allergens. Put one in the bedroom with the door closed to give you (or your sneezy kid) a good night’s sleep.  Larger models are available for open areas like greatrooms and kitchen-dining.  If you want

Allerdust allergy dusting aid

Allerdust Dusting Aid

something with a bit more style, check out the Alen Paralda purifier.

You can also tackle allergens that have settled on furniture and hard surfaces in your house by using these cool products from Allersearch, such as dusting spray, carpet treatments, and upholstery spray that neutralizes allergens on contact.

In a future post, I’ll take on vaccums with HEPA filters, and test kits that can help you determine the allergy levels in your home. For now, check out those air purifiers and allergen neutralizers, and get yourself some summer relief.