Project Results for Stockton Air Pollution Exposure Project (SAPEP)

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Project: Stockton Air Pollution Exposure Project (SAPEP)

Study Group: 18 children
Sample Collection Date: 2021

Chemical Group: Hidrocarburos Aromáticos Policíclicos (PAHs)

Measured in: Urine

Unweighted Results

Chemical measured	Indicates Exposure to	Adjusted for	Units	Number of people tested	Number of Samples	Geometric mean	95% Confidence Interval		Selected Percentiles				Detection Frequency	Reporting limit, wet weight	Notes
Chemical measured	Indicates Exposure to	Adjusted for	Units	Number of people tested	Number of Samples	Geometric mean	Lower	Upper	25th	50th	75th	90th	Detection Frequency	Reporting limit, wet weight	Notes
1-FLUO	Fluorene	NA	ng/L	18	69	*	*	*	<LOQ	29.3	50.4	110	60.9%	25.0 ng/L	‡
1-FLUO	Fluorene	Creatinine	ng/g creatinine	18	69	*	*	*	<LOQ	25.2	44.4	90.5	60.9%	25.0 ng/L	‡
1-NAP and 2-NAP	Naphthalene / carbaryl	NA	ng/L	18	69	21,900	12,700	37,900	13,600	24,500	57,400	82,200	100%	250 ng/L	‡
1-NAP and 2-NAP	Naphthalene / carbaryl	Creatinine	ng/g creatinine	18	69	19,800	13,400	29,100	9,950	19,800	38,400	56,100	100%	250 ng/L	‡
1-PHEN	Phenanthrene	NA	ng/L	18	69	77.8	58.7	103	47.0	75.2	119	221	98.6%	25.0 ng/L	‡
1-PHEN	Phenanthrene	Creatinine	ng/g creatinine	18	69	69.7	50.6	96.1	42.3	68.3	108	194	98.6%	25.0 ng/L	‡
1-PYR	Pyrene	NA	ng/L	18	69	58.9	42.3	81.8	29.7	57.7	101	185	78.3%	25.0 ng/L	‡
1-PYR	Pyrene	Creatinine	ng/g creatinine	18	69	52.2	37.9	71.9	25.6	53.0	77.8	146	78.3%	25.0 ng/L	‡
2-FLUO	Fluorene	NA	ng/L	18	69	132	89.8	195	88.4	140	219	389	97.1%	25.0 ng/L	‡
2-FLUO	Fluorene	Creatinine	ng/g creatinine	18	69	119	93.5	151	83.3	113	141	266	97.1%	25.0 ng/L	‡
2-PHEN	Phenanthrene	NA	ng/L	18	69	53.1	36.7	76.7	28.5	52.4	85.5	194	76.8%	25.0 ng/L	‡
2-PHEN	Phenanthrene	Creatinine	ng/g creatinine	18	69	47.4	34.1	65.8	29.9	46.3	69.9	123	76.8%	25.0 ng/L	‡
3-FLUO	Fluorene	NA	ng/L	18	69	46.1	32.8	64.9	27.1	39.4	66.1	154	85.5%	25.0 ng/L	‡
3-FLUO	Fluorene	Creatinine	ng/g creatinine	18	69	41.3	30.2	56.4	23.6	32.6	65.2	128	85.5%	25.0 ng/L	‡
3-PHEN and 4-PHEN	Phenanthrene	NA	ng/L	18	69	87.8	63.0	122	51.4	73.0	116	256	88.4%	50.0 ng/L	‡
3-PHEN and 4-PHEN	Phenanthrene	Creatinine	ng/g creatinine	18	69	78.5	56.9	108	46.1	72.2	120	236	88.4%	50.0 ng/L	‡

Footnotes

*Geometric mean was not calculated because the chemical was found in less than 65% of the study group
‡SAPEP collected multiple urine samples from study participants. The geometric means were estimated using random effects models to account for multiple samples per participant. Percentiles and detection frequencies were based on the total number of samples collected.

Chemical Group: Volatile Organic Compounds (VOCs)

Measured in: Urine

Unweighted Results

Chemical measured	Indicates Exposure to	Adjusted for	Units	Number of people tested	Number of Samples	Geometric mean	95% Confidence Interval		Selected Percentiles				Detection Frequency	Reporting limit, wet weight	Notes
Chemical measured	Indicates Exposure to	Adjusted for	Units	Number of people tested	Number of Samples	Geometric mean	Lower	Upper	25th	50th	75th	90th	Detection Frequency	Reporting limit, wet weight	Notes
1-MHBMA and 2-MHBMA	1,3-Butadiene	NA	µg/L	18	69	*	*	*	<LOQ	<LOQ	<LOQ	<LOQ	1.4%	0.5 µg/L	‡
1-MHBMA and 2-MHBMA	1,3-Butadiene	Creatinine	µg/g creatinine	18	69	*	*	*	<LOQ	<LOQ	<LOQ	<LOQ	1.4%	0.5 µg/L	‡
2-HPMA	Propylene oxide	NA	µg/L	18	69	41.0	26.0	64.7	28.3	43.1	71.9	133	100%	1.0 µg/L	‡
2-HPMA	Propylene oxide	Creatinine	µg/g creatinine	18	69	36.7	26.3	51.3	22.2	31.1	50.5	120	100%	1.0 µg/L	‡
3-HPMA	Acrolein	NA	µg/L	18	69	374	270	518	314	420	587	932	100%	1.0 µg/L	‡
3-HPMA	Acrolein	Creatinine	µg/g creatinine	18	69	331	274	398	223	309	444	728	100%	1.0 µg/L	‡
CNEMA	Acrylonitrile	NA	µg/L	18	69	1.66	1.06	2.60	1.38	2.45	3.28	6.07	88.4%	0.5 µg/L	‡
CNEMA	Acrylonitrile	Creatinine	µg/g creatinine	18	69	1.46	1.01	2.10	1.03	1.75	2.51	3.73	88.4%	0.5 µg/L	‡
HPMMA	Crotonaldehyde	NA	µg/L	18	69	233	152	358	168	239	417	865	100%	1.0 µg/L	‡
HPMMA	Crotonaldehyde	Creatinine	µg/g creatinine	18	69	210	167	264	138	200	276	546	100%	1.0 µg/L	‡
PMA	Benzene	NA	µg/L	18	69	*	*	*	<LOQ	<LOQ	0.180	0.360	40.6%	0.1 µg/L	‡
PMA	Benzene	Creatinine	µg/g creatinine	18	69	*	*	*	<LOQ	<LOQ	0.182	0.369	40.6%	0.1 µg/L	‡

Footnotes

*Geometric mean was not calculated because the chemical was found in less than 65% of the study group
‡SAPEP collected multiple urine samples from study participants. The geometric means were estimated using random effects models to account for multiple samples per participant. Percentiles and detection frequencies were based on the total number of samples collected.

Explanation of Terms

95% Confidence interval for the geometric mean

A 95% confidence interval for the geometric mean (CI-GM) is a range of values between two numbers called the lower bound and upper bound. These bounds are calculated based on sample data collected from a subset of a larger population. In repeated random sampling, the CI-GMs calculated for the various samples will contain the population value of the geometric mean 95 percent of the time. If convenience sampling is used to collect sample data, the CI-GM should be interpreted with caution. This is because a convenience sample may not be representative of the larger population.

95% Confidence interval for the geometric mean - lower

95% Confidence interval for the geometric mean - upper

Adjusted for

Chemical concentrations in urine can be adjusted for urine dilution using creatinine or specific-gravity. Chemical concentrations in serum can be adjusted for lipids. In the results tables, unadjusted chemical concentrations are denoted by NA.

Below the limit of detection (<LOD)

Below the limit of detection (< LOD) means that the laboratory could not detect the chemical. This may have been because the chemical was not present at all or because it was present at such a low level that the laboratory could not measure it.

Below the limit of quantification (<LOQ)

Below the limit of quantification (<LOQ) means that the chemical was not present or that it was present at such a low level that the laboratory could not measure it quantitatively with acceptable accuracy.

Chemical measured

The chemical that was analyzed in blood or urine samples. The chemical measured is sometimes the parent chemical and sometimes a metabolite of the parent chemical.

Detection frequency (percent detected)

The percentage of blood or urine samples with a measurable level of a chemical.

Geometric mean

The geometric mean is an estimated middle value of a set of numbers.This is different than the average, also called the "arithmetic mean". A geometric mean is sometimes calculated when the set of numbers contains some extreme values. For example, the geometric mean of the set of numbers "1, 2, 2, 3, 4, 5, 5, 6, 10, 100" is calculated by multiplying all ten numbers together and then raising to the 1/10th power, giving 4.8. To compare, the arithmetic mean is calculated by adding all ten numbers and dividing by 10, giving 14.

In the data tables, an asterisk (*) means the geometric mean was not calculated because the chemical was found in less than 65% of the study group.

Indicates exposure to

The chemical(s) listed in this column is the chemical(s) to which a person may have been exposed through various sources (e.g., via drinking water or use of a consumer product). This chemical is commonly called the parent chemical.

Number of people tested

The number of individuals whose blood or urine samples were analyzed for a particular chemical.

Reporting limit, wet weight

The limit of detection (LOD) and limit of quantification (LOQ) are indicators of the lowest level of a chemical the lab can measure with acceptable accuracy and precision. For some projects, this is reported as an LOD. For others, it is reported as an LOQ. The wet-weight LOD/LOQ is presented as an amount of a chemical per liter of a sample (for example, microgram of a chemical per liter of urine, or µg/L). This is often the way that biomonitoring results are reported as well (for example, µg/L urine or µg/L serum). In some cases, however, biomonitoring results are presented as lipid-adjusted concentrations (µg/g lipid) or creatinine-adjusted concentrations (µg/g creatinine). For these cases, the units for the wet-weight LOD/LOQ will differ from the units used to report the biomonitoring results. For more information on lab results and protocols, please contact us.

Sample collection date

The time period during which blood or urine samples were collected from participants in Biomonitoring California projects or laboratory collaborations.

Selected percentiles

A range of values calculated to show the distribution of measured chemical levels. See specific percentiles below for examples.

Selected percentiles - 25th

If the 25th percentile is 0.3 µg/L, for example, this means that 25% of participants had levels less than or equal to 0.3 µg/L.

Selected percentiles - 50th

If the 50th percentile is 0.6 µg/L, for example, this means that 50% of participants had levels less than or equal to 0.6 µg/L.

Selected percentiles - 75th

If the 75th percentile is 1.2 µg/L, for example, this means that 75% of participants had levels less than or equal to 1.2 µg/L.

Selected percentiles - 90th

If the 90th percentile is 1.5 µg/L, for example, this means that 90% of participants had levels less than or equal to 1.5 µg/L.

Selected percentiles - 95th

If the 95th percentile is 1.9 µg/L, for example, this means that 95% of participants had levels less than or equal to 1.9 µg/L.

Study group

A brief description of the people who provided blood and/or urine samples for analysis in a particular study.

Units

Human biomonitoring data are commonly reported as an amount of a chemical present in a specified volume of a bodily fluid (such as blood or urine). For example, a chemical measurement expressed in units of µg/L urine tells us the number of micrograms (µg) of the chemical present per one liter (L) of urine. Using standard units allows for comparison across different studies. For more examples, see definition for: Units used by Biomonitoring California.

Unweighted Results

Unweighted results summarize the measurements collected from study participants but may not apply to a wider group of Californians.

Weighted Results

Weighted results are results that have been calculated using a statistical method that adjusts over-represented and under-represented samples. Weighted results adequately reflect a wider population in California.

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Project Results for Stockton Air Pollution Exposure Project (SAPEP)

Project: Stockton Air Pollution Exposure Project (SAPEP)

Chemical Group: Hidrocarburos Aromáticos Policíclicos (PAHs)

Unweighted Results

Chemical Group: Volatile Organic Compounds (VOCs)

Unweighted Results

Explanation of Terms

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