Indoor Air Pollution: Can Houseplants Help Clean the Air?

The EPA has noted the growing body of scientific evidence showing that the air within our homes and other buildings can be much more seriously polluted than the outdoor air, even in the largest and most industrialized cities. Why would that be? Our homes contain many potential sources of pollutants; some of these sources release gases or particles continuously. For many people, the health risks from indoor air pollution may be greater that those from pollution encountered outdoors.

Some of the sources of indoor air pollution are the myriad products found inside our homes that emit volatile organic compounds (VOCs). These compounds can be a significant component of indoor air pollution. Concentrations of many VOCs are consistently higher indoors than outdoors (up to ten times higher). Some VOCs are known or suspected carcinogens.  Many more can cause a whole host of more immediate health problems

Here are just a few potential sources of VOCs that can contaminate the air in your home:

• Cabinetry, flooring or furniture made of certain pressed wood products, including particle board, hardwood plywood paneling and medium density fiberboard (MDF) can emit formaldehyde, a known carcinogen (MDF is recognized as being the highest formaldehyde-emitting pressed wood product).
•  Household cleaning and disinfecting products can contain pesticides and formaldehyde, among many other VOC-emitting ingredients.
•  Pesticides--in addition to those found in disinfecting products, pesticides can be tracked or drift into your home from lawn and garden products. Paradichlorobenzene, a commonly used active ingredient in moth repellents, is a known carcinogen.
•  Synthetic air fresheners can contain a host of toxic ingredients that can pollute indoor air, they can also contribute to formaldehyde generation through chemical reactions when sprayed inside.
• Dry-cleaned clothing emits perchloroethylene, a known carcinogen.
•  Automobile emissions from attached garages contain formaldehyde, benzene (an extremely toxic chemical and known carcinogen) and carbon monoxide.
• Carpeting and carpeting materials including backing, underlay and adhesives emit many VOCs. 

The most effective way to improve indoor air quality is to control and remove the sources of pollution.  For example, you can reduce VOCs by choosing cleaner, greener cleaning products; avoiding the use of toxic pesticides and synthetic air fresheners; and avoiding exposure to emissions from newly dry-cleaned materials.

But what about the pollution from sources that it may not be feasible to remove or replace, such as flooring, furniture or carpet? Improving ventilation to increase the amount of outdoor air coming in is another way to lower the concentrations of indoor air pollutants in your home. For example, opening windows and doors when the weather permits, and using exhaust fans in the kitchen and bathrooms.

Another way to improve air quality is to clean the air of pollutants or toxins.  A lot has been written about the ability of plants to filter pollutants out of indoor air.  Most authors reference a study published by NASA in 1989 that found that certain houseplants were very effective at removing three different VOCs, including benzene and formaldehyde, from indoor air. However, the effectiveness of plants in filtering pollutants from the air is not universally accepted. For example, the EPA report above states that “there is currently no evidence . . . that a reasonable number of houseplants remove significant quantities of pollutants in homes.” One of the issues is establishing the number of plants that would be required to filter the air in a certain amount of space.

However, more recent studies suggest that certain plants are indeed very effective at cleaning VOCs from indoor air. This Wall Street Journal article discusses some of those studies, including a 2009 University of Georgia study that identified five “super ornamental” plants that showed high rates of VOC removal.  The five were:

• ·      Purple waffle plant
•      English ivy
•      Asparagus fern
•       Purple heart plant
•      Variegated wax plant

In this 2009 TED talk an Indian environmental activist discusses how three houseplants (Areca Palm, Mother-in-law’s Tongue and Money Plant) were used in an office building in New Delhi to clean and filter the air.

Finally, I found a lot of useful information in the book How to Grow Fresh Air:  50 Houseplants That Purify Your Home or Office by the principle investigator of the NASA study. (Note: it is available from the Carnegie Library; you can request it online).

The author explains how plants clean the air and provides a directory of 50 plants that are effective for this purpose, including information on how to care for them. The plants are rated on how well they remove chemicals from the air.  Some of the most effective are:

• Areca Palm                              •   Boston Fern
• Lady Palm                               •   Peace Lily
•  Bamboo Palm                          •   Weeping Fig
• Rubber Plant                            •   Gerbera Daisy
•  Janet Craig                               •   Florist’s Mum
• English Ivy                               •   Kimberley Queen Fern
•  Dwarf Date Palm                     •   Corn Plant
• Ficus Alii

Plastics and Food (Keep 'Em Separated)

Many of us have known for a while that we should avoid plastic food and drink containers that contain BPA. However, a research article published last year strongly suggests that contact between food and any type of plastic should be avoided as much as possible.

The authors of the study, published in the journal "Environmental Health Perspectives," tested 455 plastic products designed to come into contact with food, such as baby bottles, food wrap, deli containers and plastic bags. They found that almost all of the products leached chemicals having estrogenic activity, meaning these chemicals mimic or interfere with the actions of estrogen in our bodies. This was true even of products advertised as being BPA-free.  These estrogen-mimicking chemicals, or endocrine disruptors, interfere with the functioning of our hormone systems and have been linked to a host of adverse health effects, including cancer, as well as developmental, reproductive and neurological disorders.

Furthermore, the FDA has approved more than 3,000 chemicals and other substances for use in food packaging. These are considered "indirect food additives" because they migrate from the packaging into food. The approved chemicals include known or suspected reproductive toxins or carcinogens, including BPA, formaldehyde, some phthalates, styrene (found in all styrofoam food trays and egg cartons) and various derivatives of polyvinyl chloride (PVC) (found in some cling wrap, some plastic squeeze bottles and some cooking oil bottles).

I  am in the process of gradually getting rid of plastic food containers in my kitchen. My goal is to replace the plastic in my kitchen with glass, stainless steel or ceramic. I am also working on reducing the amount of food packaged in plastic I bring home from the grocery store each week. Eliminating all plastic food packaging would be difficult for most of us. (But, for inspiration check out these tips on "zero waste" grocery shopping from a fascinating blog on "zero waste" living. Wow.)

Here are some of the steps I have taken and some resources that have been helpful:

• A great place to start is this list of tips, the Plastic-Free Living Guide, from the blog My Plastic-Free Life.
• No more bottled water; there are so many reasons to avoid bottled water. I purchased a Klean Kanteen stainless steel water bottle for each member of my family. Since I purchased them, they have started a selling a bottle called the Reflect, which comes with a stainless steel and bamboo cap. No plastic at all.
• If you are bottle-feeding a baby, use glass bottles. As noted in this article, some plastic baby bottles marketed as BPA-free use plastics made from a Bisphenol S, a substitute that itself shows estrogenic activity.
• One of the first things I wanted to get rid of were the plastic containers I used to freeze the soups and stews I like to cook. I found a great site, Life Without Plastic, that sells airtight stainless steel containers that work beautifully in the freezer. They are pricey. As I noted above, I am approaching this as a process, not something I have to do all at once, and have acquired a few containers over time.
• To store small amounts of leftovers or cut up fruits or vegetables, I generally just place the food in a bowl and invert a small plate or saucer on top. When I need an airtight seal, I place one of these silicone suction lids on a bowl. For the future, I have my eye on these Anchor Hocking glass storage dishes with glass lids and these Weck canning jars.
• I don't rewrap or transfer most of my packaged food into other containers, but I do rewrap cheese when I get home from the store. The plasticizers in some plastic wraps are fat-soluble and easily migrate into high-fat foods such as cheese and meats. (Some sources recommend slicing off a thin layer of the cheese where it comes into contact with the plastic). I rewrap cheese in unbleached parchment paper and then place it in another container. You can also try asking at the cheese counter for them to slice you a piece of cheese and wrap it in paper.
• My daughter loves using a straw to drink smoothies. I purchased these gorgeous handmade glass straws so that we wouldn't be drinking from plastic. (I know, I know, I was skeptical, too; but they really seem to be unbreakable). Reuseit.com is another great resource for reusable, waste-free products.
• Finally, for years I had been boiling water for tea in an electric kettle that was mostly plastic. I didn't even think about what I was doing until I was reading the excellent book Anticancer: A New Way of Life and the author noted that electric tea kettles are made of PVC and leach BPA. Ack. So out went the electric kettle and I dug out my old stainless steel kettle which I fortunately had kept.

Do you have any tips for eliminating plastic in the kitchen? If so, please share.

Avoiding BPA (Part 2): Receipts

I posted last week about the dangers of BPA from canned foods. We are exposed to this dangerous chemical from other sources as well. I was dismayed to learn of another avenue of exposure: thermal paper receipts (from cash registers, gas pumps and ATMs).

Two groups published studies in 2010 showing that high levels of BPA are found on thermal paper receipts. One study found large quantities of unbound or "free" BPA on half of the receipts it tested. This form of BPA is a powdery film found on the surface of receipts; it is easily transferred to our skin. The study also found 95% of dollar bills tested carried a lower amount of BPA; presumably the chemical transferred from receipts to the paper currency. The second study found what it deemed "substantial" amounts of BPA on 40% of the receipts collected from major retailers.

A more recent study, published in the fall of 2011, found BPA on 94% of the receipts tested, even on those marketed as "BPA-free." This article notes that studies have demonstrated that 27% of BPA that is transferred onto skin surfaces penetrates the skin and reaches the bloodstream within two hours.

More bad news:  the recycling of thermal paper receipts has contaminated paper products, such as paper napkins, toilet paper and food packaging with BPA, exposing us in yet other ways to this toxic chemical.

The EPA notes that the use of BPA in thermal paper could increase our cumulative exposure to this ubiquitous chemical, as well as increase direct and indirect environmental releases of BPA. It also notes the extremely high levels of BPA that can be present on a single paper receipt (in some cases 1,000 times higher than the BPA measured in canned food.) Cashiers are at greater risk of exposure; several studies have shown that cashiers and people working in retail have higher concentrations of BPA in their bodies than people in other professions. Young children are also at greater risk of exposure, because of their "hand-to-mouth" behavior. The EPA has put together a program to identify safer substitutes for BPA in the manufacture of thermal paper; a final report is due in July of this year.

What can we do to minimize our exposure to BPA from receipts? The Environmental Working Group provides some tips here including:

• Decline receipts at gas pumps, ATMs and other machines when you can
• Never give a child a receipt to hold
• Do not recycle receipts and other thermal paper! The BPA will contaminate recycled paper
• Use store services that email receipts (the J. Crew store offered me this service recently)
• Wash your hands after handling receipts, but do not use alcohol-based hand sanitizers after handling them. A study showed that these products can increase BPA absorption through the skin.

Avoiding BPA: Canned Foods

Bisphenol A (BPA) is one of the most common chemicals to which we are all exposed, and we are exposed to it on a daily basis. A study by the Centers for Disease Control found traces of BPA in the urine of 93% of the people it tested, with the highest levels being found in children. It has been found in blood samples from developing fetuses and in umbilical cord blood at birth.

These findings are a matter of great concern, especially for pregnant women and children. BPA is an endocrine disruptor. It mimics estrogen in the body, binding to the same receptors in our cells as estrogen does. Exposure to BPA has been linked to an increased risk of breast and prostate cancer, cardiovascular disease, diabetes, as well as other diseases. In addition, it has been linked to neurological and behavioral disorders in children. A recent study published in the journal Pediatrics suggested that girls born to mothers who tested high for BPA during pregnancy were more likely to experience behavioral and emotional problems as toddlers than were girls whose mothers had low levels of the chemical in their bodies.

One of the main sources of our extensive exposure to this chemical is through canned foods. BPA is used to make the epoxy resins that line most metal food cans; these linings leach BPA into the food. Another recent study by Harvard researchers showed that people who ate one serving of canned food (in the study it was canned soup) daily for five days had significantly elevated levels--a more than 1,000% increase--of BPA in their bodies.

I am determined to avoid exposing myself and my family to this chemical as much as possible. One of the ways I do this is by avoiding most canned foods. The only canned food items I purchase are Eden Organic beans. This company has been using BPA free cans since 1999.

I have found alternatives to three other items I use frequently and that I used to buy in cans: tomatoes, tomato paste and coconut milk. For soups, stews and sauces, I use Pomi chopped tomatoes; they are packaged in aseptic cartons which are BPA free. Bionaturae sells tomato paste in glass jars. I find both of these products at the Whole Foods in East Liberty.

Finally, coconut milk presented me with a challenge. I use it quite a bit for soups and stews. While I read that the brand Native Forest uses BPA free cans, I have not been able to find it in my area. It is available from Amazon, but the reviews are very mixed. My solution is to make my own from dried unsweetened coconut flakes. I found the technique in Mark Bittman's book "How to Cook Everything Vegetarian."

To make about 2 cups of coconut milk:  (1) Combine 1 cup of shredded unsweetened dried coconut with 2 cups of very hot water in a blender. Pulse on and off quickly, then turn on the blender for about 15 seconds. Let sit for a few minutes. (2) Put the mixture through a fine mesh strainer, pressing to extract as much of the liquid as possible. Discard the solids and use the milk.

It's really easy and the coconut milk works beautifully in all my recipes.

In future posts, I will be discussing other sources of exposure to BPA and how to avoid them. Do you know of any other companies that use BPA free cans, or have you found alternatives to items you used to purchase in cans?