Pesticide Residues Continue to Linger in Houses Long After Spraying

pesticides linger long after spraying

Photo by Sancho McCann

Research from the Harvard School of Public Health has determined that pesticide residues linger among public housing for some time.

Over a three year period, the researchers tested 20 families living within a Boston housing development. The families had children between three and 11 years old, and the children spent at least 80% of their nights in the house.

The researchers collected environmental air samples from inside the homes, and they analyzed samples from wiping living room floors, children’s bathroom floors and the kitchen countertops of the homes.

The research found that 38 percent of the wiped samples contained pyrethroids such as permethrin, and cypermethrin in 24 percent of the wiped samples. They also found fenthion in 24 percent of the wipes and chlorpyrifos in 7 percent of wiped samples. In addition, eight different pesticides were found among indoor air samples.

Other pesticides, such as allethrin, fenvalerate, cyhalothrin, and fenpropath were found at levels of only 2–5 percent of wiped samples.

The researchers found average concentrations of permethrin to be about 2.5 micrograms per square meter and cypermethrin concentrations to be 3.87 micrograms per square meter.

Among air samples, the researchers found Diazinon in 70 percent of samplings, while chlorpyrifos was found in 40 percent of samples. Meanwhile, half of the households air contained at least one of five pesticides.

Furthermore, the researchers found pesticide residues for pesticides that were no longer on the market – indicating an extended lingering of the pesticides long after their use.

Organophosphates banned but still sometimes used

Organophosphate pesticides were banned by the U.S. Environmental Protection Agency in 2000, but this was a phase-out ban meaning they were still in use years after the ban.

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Since then, pyrethroids have been the most commonly used indoor pesticides. This was determined in an EPA study of 168 child care centers by the U.S. This study found that 63 percent used indoor pesticides and the child care centers applied from one up to ten different pesticides – mostly organophosphates and pyrethroids. The study also found that pesticides were applied up to 107 times per year in some cases.


While there is still more research needed, there is reason to believe that childhood incidence of ADHD (attention deficit / hyperactivity disorder) is linked to early pesticide exposure in children, especially when it comes to organophosphates.

On the other side of the coin is the problem of exposure to pests that may carry disease. This has been looked at by researchers as well, with associations with allergies.

However, smarter ways of applying pesticides – and the use of less toxic pesticides is necessary. Today there are a number of less- and non-toxic natural-based pesticides that can deter pests, and this can be combined with a strictly outdoor application of other pesticides if they are desired.

The issue is demand and focus by pesticide manufacturers: If we demand non-toxic pesticides, and choose the least-toxic versions, more will be made available and they will become cheaper. The study mentioned pyrethroids as well as others.

Pyrethroids are made from flowers of pyrethrums and are accepted by most to be significantly less toxic than organophosphates. But care must be taken to avoid pesticides that combine pyrethroids with more toxic chemicals.

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Even though they are safer and will degrade faster, pyrethroids should still be applied in lower doses around children’s environments and away from surfaces children are playing on.

There are a number of other non-toxic options available – here is a website that (among others) has some interesting recipes. Other resources are available as well, and now many hardware stores carry non-toxic alternatives.

Learn how to safely cleanse and detoxify.


Lu C, Adamkiewicz G, Attfield KR, Kapp M, Spengler JD, Tao L, Xie SH. Household pesticide contamination from indoor pest control applications in urban low-income public housing dwellings: a community-based participatory research. Environ Sci Technol. 2013 Feb 19;47(4):2018-25. doi: 10.1021/es303912n.

Tulve NS, Jones PA, Nishioka MG, Fortmann RC, Croghan CW, Zhou JY, Fraser A, Cavel C, Friedman W. Pesticide measurements from the first national environmental health survey of child care centers using a multi-residue GC/MS analysis method. Environ Sci Technol. 2006 Oct 15;40(20):6269-74.

Polańska K, Jurewicz J, Hanke W. Review of current evidence on the impact of pesticides, polychlorinated biphenyls and selected metals on attention deficit / hyperactivity disorder in children. Int J Occup Med Environ Health. 2013 Mar;26(1):16-38. doi: 10.2478/s13382-013-0073-7.

Case Adams is a California Naturopath and a Board Certified Alternative Medicine Practitioner with a PhD in Natural Health Sciences. He has authored 26 books on natural healing strategies. “My journey into writing about alternative medicine began about 9:30 one evening after I finished with a patient at the clinic I practiced at over a decade ago. I had just spent the last two hours explaining how diet, sleep and other lifestyle choices create health problems and how changes in these, along with certain herbal medicines and other natural strategies can radically yet safely turn our health around. As I drove home that night, I realized this knowledge should be available to more people. So I began writing about health with a mission to reach those who desperately need this information. The strategies in my books and articles are backed by scientific evidence along with wisdom handed down through traditional medicines for thousands of years.”

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