ATHENS, GA—Air quality in homes, offices, and other indoor spaces is becoming a major health concern, particularly in developed countries where people often spend more than 90% of their time indoors. Surprisingly, indoor air has been reported to be as much as 12 times more polluted than outdoor air in some areas. Indoor air pollutants emanate from paints, varnishes, adhesives, furnishings, clothing, solvents, building materials, and even tap water. A long list of volatile organic compounds, or VOCs [including benzene, xylene, hexane, heptane, octane, decane, trichloroethylene (TCE), and methylene chloride], have been shown to cause illnesses in people who are exposed to the compounds in indoor spaces. Acute illnesses like asthma and nausea and chronic diseases including cancer, neurologic, reproductive, developmental, and respiratory disorders are all linked to exposure to VOCs. Harmful indoor pollutants represent a serious health problem that is responsible for more than 1.6 million deaths each year, according to a 2002 World Health Organization report. 

Stanley J. Kays, Department of Horticulture, University of Georgia, was the lead researcher of a study published in HortScience that tested ornamental indoor plants for their ability to remove harmful VOCs from indoor air. According to Kays, some indoor plants have the ability to effectively remove harmful VOCs from the air, and not only have the ability to improve our physical health, but also have been shown to enhance our psychological health. Adding these plants to indoor spaces can reduce stress, increase task performance, and reduce symptoms of ill health. 

The ability of plants to remove VOCs is called “phytoremediation”. To better understand the phytoremediation capacity of ornamental plants, the research team tested 28 common indoor ornamentals for their ability to remove five volatile indoor pollutants. “The VOCs tested in this study can adversely affect indoor air quality and have a potential to seriously compromise the health of exposed individuals,” Kays explained. “Benzene and toluene are known to originate from petroleum-based indoor coatings, cleaning solutions, plastics, environmental tobacco smoke, and exterior exhaust fumes emanating into the building; octane from paint, adhesives, and building materials; TCE from tap water, cleaning agents, insecticides, and plastic products; and alpha-pinene from synthetic paints and odorants.” 

During the research study, plants were grown in a shade house for eight weeks followed be acclimatization for twelve weeks under indoor conditions before being placed in gas-tight glass jars. The plants were exposed to benzene, TCE, toluene, octane, and alpha-pinene, and air samples were analyzed. The plants were then classified as superior, intermediate, and poor, according to their ability to remove VOCs. 

Of the 28 species tested, Hemigraphis alternata (purple waffle plant), Hedera helix (English ivy), Hoya carnosa (variegated wax plant), and Asparagus densiflorus (Asparagus fern) had the highest removal rates for all of the VOCs introduced. Tradescantia pallida (Purple heart plant) was rated superior for its ability to remove four of the VOCs. 

The study concluded that simply introducing common ornamental plants into indoor spaces has the potential to significantly improve the quality of indoor air. In addition to the obvious health benefits for consumers, the increased use of indoor plants in both ”green” and traditional buildings could have a tremendous positive impact on the ornamental plant industry by increasing customer demand and sales. 

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The complete study and abstract are available on the ASHS HortScience electronic journal web site: http://hortsci.ashspublications.org/cgi/content/abstract/44/5/1377

Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at ashs.org

“It’s well established that schools with large minority populations tend to have lower quality teachers,” Dr. Jackson said. “But it is unclear whether these schools are merely located in areas with a paucity of quality teachers, whether quality teachers avoid these schools because of the neighborhood or economic factors surrounding a school, or whether there is a direct relationship between student characteristics and teacher quality.”

Dr. Jackson’s findings suggest that it’s not neighborhoods keeping high-quality teachers away; it’s the students-and it’s directly related to their race.

“This is particularly sobering because it implies that, all else equal, black students will systematically receive lower quality instruction,” Jackson said. “This relationship may be a substantial contributor to the black-white achievement gap in American schools.”

The study focused on the Charlotte-Mecklenberg school district in North Carolina. In 2002, the district ended its race-based busing program, which distributed the district’s minority population across its schools. When the policy ended, some schools had a large and sudden inflow of black students. Since the racial makeup of the schools changed suddenly but the neighborhood and economic factors surrounding them stayed the same, Jackson could test the impact the student body itself had on teacher quality.

Using data supplied by the North Carolina Education Research Data Center, Jackson found that schools that had an increase in black enrollment suffered a decrease in their share of high-quality teachers, as measured by years of experience and certification test scores. Teacher effectiveness, as measured by teachers’ previous ability to improve student test scores, decreased in the black inflow schools as well. The change in quality for each school generally occurred in the same year that the busing program ended, indicating that teachers moved in anticipation of more black students.

“This study implies teachers may prefer a student body that is more white and less black,” Jackson says.

Black teachers were slightly more likely than white teachers to stay in the schools that experienced a black inflow, the study found. However, those black teachers who did leave black schools tended to be the highest qualified black teachers. So the decline in quality was somewhat more pronounced among black teachers than white teachers.

Just what it is about black students that pushes high-quality teachers away is hard to pin down, Dr. Jackson says. It could be that teachers are reacting to notions about black students’ achievement or income levels.

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C. Kirabo Jackson, “Student Demographics, Teacher Sorting, and Teacher Quality: Evidence from the End of School Desegregation,” Journal of Labor Economics 27:2.

Since 1983, the Journal of Labor Economics has presented international research that examines issues affecting the economy as well as social and private behavior. The Journal publishes both theoretical and applied research results relating to the U.S. and international data. And its contributors investigate various aspects of labor economics, including supply and demand of labor services, personnel economics, distribution of income, unions and collective bargaining, applied and policy issues in labor economics, and labor markets and demographics.

This article was reposted from the University of Chicago Press Journals.

“Place of residence plays a larger role in dietary health than previously estimated,” said Manuel Franco, MD, PhD, lead author of the studies and an associate with the Bloomberg School’s Department of Epidemiology. “Our findings show that participants who live in neighborhoods with low healthy food availability are at an increased risk of consuming a lower quality diet. We also found that 24 percent of the black participants lived in neighborhoods with a low availability of healthy food compared with 5 percent of white participants.” 

Researchers conducted a cross-sectional study to examine the association between the availability of healthy foods and diet quality among 759 participants of a population-based cardiovascular cohort study, the Multi-Ethnic Study of Atherosclerosis (MESA). Using a food frequency questionnaire, Franco, along with colleagues from the Johns Hopkins School of Medicine, the University of Michigan and the University of Texas, summarized diet into two dietary patterns reflecting low and high quality diet. The availability of healthy foods was assessed by examining food stores within MESA participants’ neighborhood or census tract, their closest food store and all food stores within one mile of the participants’ residence. Availability of healthy foods in each food store was assessed by measuring the availability of items like fresh fruits and vegetables, skim milk and whole wheat bread as recommended by the U.S. Department of Agriculture. Their findings were reported in the American Journal of Clinical Nutrition.

In the American Journal of Preventive Medicine, Franco, along with colleagues from the Johns Hopkins School of Medicine and the University of Michigan, examined the differences in the availability of healthy foods across 159 neighborhoods and 226 neighborhood stores in Baltimore City and Baltimore County. Researchers found that 43 percent of predominantly black neighborhoods and 46 percent of lower-income neighborhoods fell under the category of low availability of healthy foods versus 4 percent and 13 percent, respectively, in predominantly white and higher-income neighborhoods. In addition, supermarkets in predominantly white and higher-income neighborhoods had higher levels of healthy food availability compared to supermarkets located in lower-income neighborhoods and predominantly black neighborhoods.

“Previous studies have suggested that race and income are related to healthy food intake and our choice of foods play a major role in our health and diet,” said Benjamin Caballero, MD, PhD, professor at the Bloomberg School’s Department of International Health. “Our studies show that where you live is a major determinant of your health. The joint efforts of public health researchers in collaboration with community groups and policymakers will be required to effectively change the current picture of the less-than-optimal availability of recommended healthy foods.”

“Availability of Health Foods and Dietary Patterns: The Multi-Ethnic Study of Atheroscerosis” was written by Manuel Franco, Ana V. Diez-Roux, Jennifer A. Nettleton, Mariana Lazo, Frederick L. Brancati, Benjamin Caballero, Thomas A. Glass and Latetia V Moore.

“Neighborhood Characteristics and Availability of Healthy Foods in Baltimore” was written by Manuel Franco, Ana V. Diez Roux, Thomas A. Glass, Benjamin Caballero and Frederick L. Brancati.

Reprinted from Johns Hopkins University Bloomberg School of Public Health.