These Key Findings summarize the most important findings from each of the indicators in ACE3. Please see the body of the report for background information on the indicators. Note that the years for which data are available varies across the indicators. 

For many of the indicators in ACE3, evidence of relationships between environmental exposures and children’s health continues to evolve. Just because an indicator is included in this report, it doesn’t necessarily mean there is a known relationship between exposures to a specific environmental contaminant and impacts on children’s health.

On this page:

• Environments and Contaminants
• Biomonitoring
• Health
• Supplementary Topics

Environments and Contaminants

Criteria Air Pollutants

• From 1999 to 2013, the proportion of children living in counties with measured pollutant concentrations above the levels of one or more national ambient air quality standards decreased from 75% to 50%. This includes both concentrations above the level of any current short-term standard at least once during the year as well as average concentrations above the level of any current long-term standards.
• In 2013, 6% of children lived in counties with measured ozone concentrations above the level of the 8-hour ozone standard on more than 25 days. An additional 2% of children lived in counties with measured concentrations above the level of the ozone standard between 11 and 25 days, and 11% of children lived in counties where concentrations were above the level of the standard between 4 and 10 days.
• In 2013, 2% of children lived in counties with measured fine particle (PM2.5) concentrations above the level of the 24-hour PM2.5 standard on more than 25 days. An additional 1% of children lived in counties with measured concentrations above the level of this standard between 11 and 25 days, and 1% of children lived in counties with measured concentrations above the level of the 24-hour PM2.5 standard between 8 and 10 days.
• Based on categories from EPA’s Air Quality Index, the percentage of children’s days that were designated as having “unhealthy” air quality decreased from 9% in 1999 to 3% in 2013. The percentage of children’s days with “good” air quality increased from 39% in 1999 to 52% in 2013. The percentage of children’s days with “moderate” air quality was approximately constant at 24-29% from 1999 to 2013.

Hazardous Air Pollutants

• In 2005, nearly all children (99.9%) lived in census tracts in which hazardous air pollutant (HAP) concentrations combined to exceed the 1-in-100,000 cancer risk benchmark. Seven percent of children lived in census tracts in which HAPs combined to exceed the 1-in-10,000 cancer risk benchmark. Fifty-six percent of children lived in census tracts in which at least one HAP exceeded the benchmark for health effects other than cancer.

Indoor Environments

• In 2010, 6% of children ages 0 to 6 years lived in homes where someone smoked regularly, compared with 27% in 1994.
• In 2005-2006, 15% of children ages 0 to 5 years lived in homes with either an interior lead dust hazard or an interior deteriorated lead-based paint hazard, compared with 22% in 1998-1999.

Drinking Water Contaminants

• The estimated percentage of children served by community drinking water systems that did not meet all applicable health-based standards declined from 18% in 1993 to about 5% in 2001. Since 2002, this percentage has fluctuated between 6% and 12%, and was 6% in 2013.
• Between 1993 and 2009, the estimated percentage of children served by community water systems that had at least one monitoring and reporting violation fluctuated between about 10% and 22%, and was 14% in 2013.

Chemicals in Food

• In 1999, 81% of sampled apples had detectable organophosphate pesticide residues, and in 2009, 35% had detectable residues. In 2000, 10% of sampled carrots had detectable organophosphate pesticide residues, and in 2007, 5% had detectable residues. In 2000, 21% of sampled grapes had detectable organophosphate pesticide residues, and in 2009, 8% had detectable residues. In 1998, 37% of sampled tomatoes had detectable organophosphate pesticide residues, and in 2008, 9% had detectable residues.

Contaminated Lands

• As of 2009, approximately 6% of all children in the United States lived within one mile of a Corrective Action or Superfund site that may not have had all human health protective measures in place.
• Approximately 21% of all children living within one mile of a Corrective Action or Superfund site that may not have had all human health protective measures in place were Black, while 15% of children in the United States as a whole are Black.

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Biomonitoring

Lead

• The median concentration of lead in the blood of children between the ages of 1 and 5 years dropped from 15 micrograms per deciliter (µg/dL) in 1976-1980 to 1.0 µg/dL in 2011-2012, a decrease of 93%. At the 95th percentile, blood lead levels dropped from 29 µg/dL in 1976-1980 to 2.9 µg/dL in 2011-2012, a decrease of 90%.
• The median blood lead level in Black non-Hispanic children ages 1 to 5 years in 2009-2012 was 1.4 µg/dL, higher than the level of 1.0 µg/dL in White non-Hispanic children, Mexican-American children, and children of “All Other Races/Ethnicities.”

Mercury

• The median concentration of total mercury in the blood of women ages 16 to 49 years has shown little change between 1999-2000 and 2011-2012, and was 0.6 micrograms per liter (µg/L) in 2011-2012.
• Among women in the 95th percentile of exposure, the concentration of total mercury in blood decreased from 7.4 µg/L in 1999-2000 to 3.7 µg/L in 2001-2002. From 2001-2002 to 2011-2012, the 95th percentile of total blood mercury remained between 3.7 and 4.5 µg/L.

Cotinine

• The median level of cotinine (a marker of exposure to environmental tobacco smoke) measured in blood serum of nonsmoking children ages 3 to 17 years dropped from 0.25 nanograms per milliliter (ng/mL) in 1988-1991 to 0.03 ng/mL in 2009-2010, a decrease of 88%. Cotinine values at the 95th percentile decreased by 34% from 1988-1991 to 2009-2010.
• The median level of cotinine measured in blood serum of nonsmoking women ages 16 to 49 years dropped from 3.2 ng/mL in 1988-1991 to 2.1 ng/mL in 2009-2010, a decrease of 86%. Cotinine values at the 95th percentile decreased by 35% from 1988-1991 to 2009-2010.

Perfluorochemicals (PFCs)

• Between 1999-2000 and 2007-2008, median blood serum levels of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in women ages 16 to 49 years showed a decreasing trend; median levels of perfluorononanoic acid (PFNA) showed an increasing trend; and median levels of perfluorohexane sulfonic acid (PFHxS) remained relatively constant over time.

Polychlorinated Biphenyls (PCBs)

• In 2001-2004, the median level of polychlorinated biphenyls (PCBs), summing together four selected PCBs, in blood serum of women ages 16 to 49 years was 30 nanograms per gram (ng/g) lipid. Data are not yet available for comparing these PCB levels over time.

Polybrominated Diphenyl Ethers (PBDEs)

• The median concentration of polybrominated diphenyl ethers (PBDEs) in blood serum of women ages 16 to 49 years was 44 ng/g lipid in 2003-2004. Data are not yet available for comparing these PBDE levels over time.

Phthalates

• From 2001-2002 to 2007-2008, the median level of di-2-ethylhexyl phthalate (DEHP) metabolites in urine of women ages 16 to 49 years varied between 41 μg/L and 51 μg/L, and was 51 μg/L in 2007-2008. From 1999-2000 to 2007-2008, the median level of dibutyl phthalate (DBP) metabolites in women ages 16 to 49 years varied between 27 μg/L and 36 μg/L, and was 36 μg/L in 2007-2008. From 1999-2000 to 2007-2008, the median level of butyl benzyl phthalate (BBzP) metabolites in women ages 16 to 49 years varied between 10 μg/L and 14 μg/L, and was 12 μg/L in 2007-2008.
• From 2001-2002 to 2007-2008, the median level of DEHP metabolites in urine of children ages 6 to 17 years varied between 45 μg/L and 62 μg/L, and was 45 μg/L in 2007-2008. From 1999-2000 to 2007-2008, the median level of DBP metabolites in children ages 6 to 17 years varied between 36 μg/L and 42 μg/L, and was 41 μg/L in 2007-2008. The median level of BBzP metabolite in children ages 6 to 17 years decreased from 25 μg/L in 1999-2000 to 16 μg/L in 2007-2008.

Bisphenol A (BPA)

• From 2003-2004 to 2009-2010, the median concentration of bisphenol A (BPA) in urine among women ages 16 to 49 years varied between 2 µg/L and 3 µg/L. From 2003-2004 to 2009-2010, the concentration of BPA in urine at the 95th percentile varied between 10 µg/L and 16 µg/L, and was 10 µg/L in 2009-2010.
• Among children ages 6 to 17 years the median concentration of BPA in urine decreased from 4 µg/L in 2003-2004 to 2 µg/L in 2009-2010. The concentrations of BPA in urine at the 95th percentile decreased from 16 µg/L in 2003-2004 to 10 µg/L 2009-2010.

Perchlorate

• From 2001-2002 to 2007-2008, the median level of perchlorate in urine among women ages 16 to 49 years was 3 μg/L with little variation over time. Over the same period, the 95th percentile varied between 13 and 17 μg/L.

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Health

Respiratory Diseases

• The proportion of children reported to currently have asthma has increased from 8.7% in 2001 to 9.3% in 2012, but then decreased to 8.3% in 2013.
• In 2010-2013, the percentages of Black non-Hispanic children and children of “All Other Races” reported to currently have asthma, 15.4% and 11.5% respectively, were greater than for Hispanic children (8.5%), White non-Hispanic children (7.9%), and Asian non-Hispanic children (5.9%).
• The rate of emergency room visits for asthma decreased from 114 visits per 10,000 children in 1996 to 99 visits per 10,000 children in 2010. Between 1996 and 2010, hospitalizations for asthma and all other respiratory causes decreased from 90 hospitalizations per 10,000 children to 64 hospitalizations per 10,000 children.

Childhood Cancer

• The age-adjusted annual incidence of cancer increased from 1992-2009. The incidence ranged from 153 to 161 cases per million children between 1992 and 1994 and from 172 to 175 cases per million children between 2007 and 2009.
• Childhood cancer mortality has decreased from 33 deaths per million children in 1992 to 24 deaths per million children in 2009.
• Leukemia was the most common cancer diagnosis for children from 2004-2006, representing 28% of total cancer cases. Incidence of acute lymphoblastic (lymphocytic) leukemia increased from 30 cases per million in 1992-1994 to 35 cases per million in 2004-2006. The rate of acute myeloid (myelogenous) leukemia was 7 cases per million in 1992-1994 and 9 cases per million in 2004-2006.

Neurodevelopmental Disorders

• From 1997 to 2013, the proportion of children ages 5 to 17 years reported to have ever been diagnosed with attention-deficit/hyperactivity disorder (ADHD) increased from 6.3% in 1993 to 10.7% in 2012 and 9.9% in 2013.
• In 2013, 8.2% of children ages 5 to 17 years had ever been diagnosed with a learning disability. There was little change in this percentage between 1997 and 2013.
• The percentage of children ages 5 to 17 years reported to have ever been diagnosed with autism increased from 0.1% in 1997 to 1.2% in 2013.
• In 2013, 1.4% of children ages 5 to 17 years were reported to have ever been diagnosed with intellectual disability (mental retardation). The percentage fluctuated between 0.6% and 0.9% from 1997 to 2010, and was between 1.3% and 1.4% from 2011 to 2013.

Obesity

• Between 1976-1980 and 2007-2008, the percentage of children identified as obese showed an increasing trend. In 1976-1980, 5% of children ages 2 to 17 years were obese. This percentage reached a high of 17% in 2007-2008. Between 1999-2000 and 2007-2008, the percentage of children identified as obese remained between 15% and 17%.
• In 2005-2008, a higher percentage of Mexican-American and Black non-Hispanic children were obese at 22% and 20%, respectively, compared with 14% of White non-Hispanic children and 14% of children of “All Other Races/Ethnicities.”

Adverse Birth Outcomes

• Between 1993 and 2008, the rate of preterm birth showed an increasing trend, ranging from 11.0% in 1993 to its highest value of 12.8% in 2006.
• Between 1993 and 2008, the rate of term low birth weight for all races/ethnicities stayed relatively constant, ranging between 2.5% and 2.8%.

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Supplementary Topics

The Supplementary Topics section presents topics for which adequate national data are not available, but for which more targeted data collection efforts could be used to provide measures illustrating additional children’s environmental health issues of interest. Data sets used for these measures are representative of particular locations (such as a single state) and/or were surveys conducted a single time rather than on a continuing or periodic basis. Since these data sets are lacking in certain key elements desirable for ACE3 indicators, data presentations for the Supplementary Topics are referred to as “measures” rather than “indicators.”

Birth Defects

• The rates for all categories of birth defects in Texas have increased or remained stable for the period of 1999-2007. Some of the biggest increases were seen for musculoskeletal defects, cardiac and circulatory defects, genitourinary defects, eye and ear defects, and central nervous system defects.

Contaminants in Schools and Child Care Facilities

• The pesticides chlorpyrifos, cis-permethrin, and diazinon were detected in all dust samples collected at Ohio and North Carolina child care centers in 2000-2001. Chlorpyrifos and diazinon were also detected in all indoor air samples collected at these child care centers.
• Dibutyl phthalate was detected in all indoor air and dust samples collected at Ohio and North Carolina child care centers.
• Pyrethrin and pyrethroid insecticides accounted for the greatest volume of pesticide use in California schools overall from 2002 to 2007.

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