Got questions? Ask the Green Geek.

Green Geek LogoWondering if there's an environmentally friendly way to fight mosquitoes? If the sun contributes to global warming? Or how to lower your A/C usage?

Ask the Green Geek.

Pima County FYI has a monthly column featuring questions and answers on all things green. Our own Green Geek gets assistance on answering your questions from the sustainability experts in Pima County's Office of Sustainability and Conservation.

Send your questions to And look for the column the second Friday of each month on the left sidebar of the newsletter.

Dear Green Geek,

Mosquitos love me, but I’m weary of the health and environmental effects of bug spray. Are there natural ways to fend them off? 



Hi, Astrid,

Ah yes, these pesky critters can certainly be a BUZZ-kill when trying to enjoy the warmer weather! There are natural alternatives to the conventional stuff but it’s important to use repellents that best suit your needs. 

First, some background on DEET, the most widely used and studied insect repellent  in the United States. The general consensus among experts is that the chemical is safe and very effective for adults and children, when used as directed. The EPA concluded that when consumers followed product-label instructions and took reasonable precautions, the health risks of DEET essentially vanished. It is also not classified as a carcinogen. And for the most part, DEET is not harmful to the environment. 

That said, you are not the only one who’s uncomfortable with dousing themselves in  conventional bug spray. A recent Consumer Reports survey of 2,011 adults in the U.S. found that just one-third believe existing insect repellents are safe for adults, and even fewer -- just under one-quarter -- think they're safe for children. There have also been a small number of studies that have associated prolonged and consistent exposure to DEET with illness and brain cell damage. Chances are you’re not subjecting yourself to a level even close to that in the studies, but there is still cause for caution. 

If you’re still set on using more natural alternatives to DEET, here are a couple of popular options: 

Oil of Lemon Eucalyptus (OLE)
What is it? It’s important not to confuse this product with lemon eucalyptus oil. The names are very similar, but the two chemicals are quite different. OLE is an oil extracted from the gum eucalyptus tree. The actual extracted chemical is called PMD and has demonstrated efficacy as an insect repellent.

Does it work? Yes. Testing has generally found that this ingredient is an effective alternative to DEET.

Is it safe? The EPA classifies PMD as a biopesticide. Both federal regulators and our experts agree that OLE is relatively safe. But it’s important to use OLE repellents carefully and as directed, because when misapplied they can cause temporary eye injury. The product hasn’t been well-tested on children, and the Centers for Disease Control and Prevention and Consumer Reports advise against using OLE-based repellents on children younger than three.

What is it? The picaridin molecule is synthetic, meaning it’s made in a laboratory by chemists. But it was modeled after -- and closely resembles -- a chemical found naturally in black pepper plants.

Does it work? Research suggests that at concentrations of at least 20 percent, picaridin can provide as much protection from bug bites as DEET.

Is it safe? Repellents containing picaridin are EPA-registered and subject to the same level of EPA safety evaluation as DEET and other synthetic chemicals. The agency found that picaridin is safe, even for use on infants. But use as directed, because if misapplied picaridin can irritate your skin and eyes.

What are they? Botanical repellents, which are those most likely to have "natural" on product labeling, can include any number of plant-based chemicals. Some common ones are lemon grass, citronella, peppermint, geraniol, soybean, and rosemary. Those ingredients can be oils extracted directly from plants or synthetic chemicals that exactly replicate their natural counterparts. 
Applying insect repellant
Do they work? These products aren’t registered with the EPA. As a result, the companies that make botanical products aren’t required to prove to federal regulators that they actually work. Consumer Reports has tested several varieties and found that they don’t work well overall.

Are they safe? Yes and no. The chemicals in these products are unlikely to cause you any serious harm themselves, though they do contain known allergens, often at much higher concentrations than other natural products. But by using an unregistered botanical repellent, you run the risk of exposing yourself to vector-borne diseases. 

Other ways to protect yourself from mosquitoes: 
  • Cover up when you go outside
  • Turn on a fan nearby
  • Eliminate standing water to minimize breeding
  • Stay inside from dawn to dusk if possible
When deciding what type of mosquito repellent to use, you should consider how long you will be outside; how many mosquitoes are in your area; and the risk of mosquito-transmitted diseases where you live. 

Stay safe out there!

Seek help. If your anxiety around environmental issues begins to disrupt your daily life and well being, it may be time to speak with someone about it. There is even a small but growing number of eco-therapists that are trained in this specific area.

Green Geek

Dear Green Geek,

I know greenhouse gas emissions are a cause of global warming, but what about the sun? Is it also a cause?



Hi, Linda, 

Nope. While the sun can influence the Earth’s climate, it is not responsible for the warming trend we’ve seen over the past few decades. According to NASA, we know subtle changes in the Earth’s orbit around the sun are responsible for the comings and goings of the ice ages, but the warming we’ve seen in recent years is too rapid to be linked to changes in Earth’s orbit and too large to be caused by solar activity.

If the sun were causing global warming we would expect to see a rise in the amount of the sun’s energy that hits the top of the atmosphere. Since 1978, scientists have been tracking this using sensors on satellites and what they tell us is that there has been no upward trend in the amount of the sun’s energy reaching Earth. 

And according to NASA, if the sun were responsible for global warming, we should see warming throughout all layers of the atmosphere, from the surface all the way up to the upper atmosphere (stratosphere). But what we actually see is warming at the surface and cooling in the stratosphere. This is consistent with the warming being caused by a build-up of heat-trapping gases near the surface of the Earth, and not by the sun getting “hotter.”

Great question!
Green Geek

Dear Green Geek,

I’ve been needing to use the A/C more and more in recent years and my electric bills are through the roof! Any tips to lower my A/C usage while still keeping cool?



Hi, Jeff, 
I’m sure you’re not the only one facing this issue! Longer and hotter summers usually mean higher cooling costs. And while an increase in A/C usage is likely, there are some steps you can take to reduce your A/C bill. 
  • Use a ceiling fan or other circulating fan. It can make you feel six or seven degrees cooler via the wind-chill effect.
  • Be conservative with your A/C use. According to the U.S. Department of Energy, setting your A/C as high as comfortably possible and using a programmable thermostat to increase temperature when you’re out, or asleep, could easily decrease your summer cooling bill by 10 percent. And if you’re coming into a hot house, remember that turning the A/C to a colder-than-normal setting won’t cool rooms faster; it’ll just keep the A/C running longer. 
  • Maintain your cooling system so it’s running optimally. Just cleaning and/or replacing filters once per month will lower an A/C’s energy consumption by 5 to 15 percent. A unit’s evaporator and condenser coils (located outside) should also be clear of debris and foliage should remain at least two feet from the condenser.
  • Avoid heat-producing activities in your home during the day, like cooking, showering and using the dishwasher or clothes dryer. If you can, wait to do these activities until it’s cooler outside.
  • Close curtains, blinds and shades to prevent outdoor heat from radiating inside. Highly reflective blinds can reduce solar heat gain by around 45 percent when completely closed and lowered on a sunny window.
  • Upgrade and seal your windows so that they are energy-efficient and leak proof.
  • Go solar. A big move but one that will greatly reduce cooling costs! 
Properly inflate your tires
Keep your engine well-tuned
Plan multi-stop trips ahead of time to ensure you’re taking the most efficient route
Avoid left turns when you can
Prefer roundabouts when available 

Stay cool!
Green Geek
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