TABLE OF CONTENTS

7. INHALATION ROUTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.2 INHALATION RATE STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.2.1 Linn et al., 1992 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

7.2.2 Spier et al., 1992 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

7.2.3 Adams, 1993 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

7.2.4 Layton, 1993 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

7.2.5 Rusconi et al., 1994 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7

7.2.6 Lordo et al., 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9

7.3 RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11

7.4 REFERENCES FOR CHAPTER 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12

APPENDIX 7A

VENTILATION DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-38
LIST OF TABLES

Table 7-1. Calibration And Field Protocols For Self-monitoring of Activities Grouped by

Subject Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-13

Table 7-2. Subject Panel Inhalation Rates by Mean VR, Upper Percentiles, And Self-estimated

Breathing Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-13

Table 7-3. Distribution of Predicted Intake Rates by Location And Activity Levels For

Elementary And High School Students . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14

Table 7-4. Average Hours Spent Per Day in a Given Location and Activity Level For

Elementary and High School Students . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14

Table 7-5. Distribution Patterns of Daily Inhalation Rates For Elementary (EL) And High

School (HS) Students Grouped by Activity Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15

Table 7-6. Summary of Average Inhalation Rates (m3/hr) by Age Group And Activity Levels for

Laboratory Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-16

Table 7-7. Summary of Average Inhalation Rates (m3/hr) by Age Group And Activity Levels in

Field Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17

Table 7-8. Comparisons of Estimated Basal Metabolic Rates (BMR) With Average Food-energy

Intakes (EFD) For Individuals Sampled in The 1977-78 NFCS . . . . . . . . . . . . . . . . . 7-18

Table 7-9. Daily Inhalation Rates Calculated From Food-energy Intakes . . . . . . . . . . . . . . . 7-19

Table 7-10. Daily Inhalation Rates Obtained From The Ratios Of Total Energy Expenditure to

Basal Metabolic Rate (BMR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-20

Table 7-11. Inhalation Rates For Short-term Exposures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-21

Table 7-12. Mean, Median, and SD of Respiratory Rate According to Waking or Sleeping in

618 Infants and Children Grouped in Classes of Age . . . . . . . . . . . . . . . . . . . . . . . . . 7-22

Table 7-13. Descriptive Statistics for Daily Average Ventilation Rate (L/min) in Males, by Age

Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-24

Table 7-14. Descriptive Statistics for Daily Average Ventilation Rate (L/min) in Females, by

Age Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-25

Table 7-15. Average Time Spent Per Day Performing Activities Within Specified Intensity

Categories, and Average Ventilation Rates Associated With These Activity Categories,

for Males According to Age Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-26

Table 7-16. Average Time Spent Per Day Performing Activities Within Specified Intensity

Categories, and Average Ventilation Rates Associated With These Activity Categories,

for Females According to Age Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29

Table 7-17. Descriptive Statistics for Daily Average Ventilation Rate (m3

/day) in Males, by Age

Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-32

Table 7-18. Descriptive Statistics for Daily Average Ventilation Rate (m3

/day) in Females, by

Age Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-33

Table 7-19. Descriptive Statistics for Duration of Time (hr/day) Spent Performing Activities

Within the Specified Activity Category, by Age and Gender Categories

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-34

Table 7-20. Confidence in Inhalation Rate Recommendations . . . . . . . . . . . . . . . . . . . . . . . 7-36

Table 7-21. Summary of Recommended Values For Inhalation . . . . . . . . . . . . . . . . . . . . . . 7-37
LIST OF FIGURES

Figure 7-1. 5th, 10th, 25th, 50th, 75th, 90th, and 95th Smoothed Centiles by Age in Awake

Subjects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-23

Figure 7-2. 5th, 10th, 25th, 50th, 75th, 90th, and 95th Smoothed Centiles by Age in Asleep

Subjects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-23
7-1

1 7. INHALATION ROUTE

2

3 7.1 INTRODUCTION

4 This chapter presents data and recommendations for inhalation rates that can be used to

5 assess children’s exposure to contaminants in air. Inhalation rates vary with both size and

6 activity level, both of which influence oxygen consumption. Infants and young children have a

7 higher resting metabolic rate and rate of oxygen consumption per unit body weight than do

8 adults because they have a larger cooling surface per unit body weight and because they are

9 growing rapidly. The oxygen consumption of a resting infant aged between one week and one

10 year is 7 mL/kg body weight per minute. The rate for an adult under the same conditions is 3-5

11 mL/kg per minute (WHO, 1986). Thus, while on an absolute basis, greater amounts of air and

12 pollutants are inhaled by adults than children per similar time periods, on a body-weight basis,

13 the volume of air passing through the lungs of a resting infant is twice that of a resting adult

14 under the same conditions. The recommended inhalation rates for children are summarized in

15 Section 7.3. 

16

17 7.2 INHALATION RATE STUDIES

18 7.2.1 Linn et al., 1992 

19 Linn et al. (1992) conducted a study that estimated the inhalation rates for "high-risk"

20 subpopulation groups exposed to ozone in their daily activities in the Los Angeles area. The

21 population surveyed consisted of several panels of both adults and children. The panels

22 consisting of children included Panel 2: 17 healthy elementary school students (5 males and 12

23 females, ages 10-12 years); Panel 3: 19 healthy high school students (7 males and 12 females,

24 ages 13-17 years); Panel 6: 13 young asthmatics (7 males and 6 females, ages 11-16 years). 

25 An initial calibration test was conducted, followed by a training session. Finally, a field

26 study that involved the subjects collecting their own heart rate and diary data was conducted. 

27 During the calibration tests, ventilation rate (VR), breathing rate, and heart rate (HR) were

28 measured simultaneously at each exercise level. From the calibration data an equation was

29 developed using linear regression analysis to predict VR from measured HR.

30 In the field study, each subject recorded in diaries their daily activities, change in

31 locations (indoors, outdoors, or in a vehicle), self-estimated breathing rates during each
7-2

1 activity/location, and time spent at each activity/location. Healthy subjects recorded their HR

2 once every 60 seconds using a Heart Watch, an automated system consisting of a transmitter and

3 receiver worn on the body. Asthmatic subjects recorded their diary information once every hour. 

4 Subjective breathing rates were defined as slow (walking at their normal pace), medium (faster

5 than normal walking), and fast (running or similarly strenuous exercise). Table 7-1 presents the

6 calibration and field protocols for self-monitoring of activities for each subject panel.

Table 7-2 presents the mean, 99th 7 percentile, and mean VR at each subjective activity

8 level (slow, medium, fast). The mean and 99th percentile VR were derived from all HR

9 recordings that appeared to be valid, without considering the diary data. Each of the three

10 activity levels was determined from both the concurrent diary data and HR recordings by direct

11 calculation or regression. The authors reported that the diary data showed that on a typical day,

12 most individuals spent most of their time indoors at slow activity level. During slow activity,

13 asthmatic subjects had higher VRs than healthy subjects (Table 7-2). The authors also reported

14 that in every panel the predicted VR correlated significantly with the subjective estimates of

15 activity levels. 

16 A limitation of this study is that calibration data may overestimate the predictive power

17 of HR during actual field monitoring. The wide variety of exercises in everyday activities may

18 result in greater variation of the VR-HR relationship than was calibrated. Another limitation is

19 the small sample size of each subpopulation surveyed. An advantage of this study is that diary

20 data can provide rough estimates of ventilation patterns which are useful in exposure

21 assessments. Another advantage is that inhalation rates were presented for both healthy and

22 asthmatic children.

23

24 7.2.2 Spier et al., 1992

25 Spier et al. (1992) investigated the activity patterns of 17 elementary school students (10-

26 12 years old) and 19 high school students (13-17 years old) in suburban Los Angeles from late

27 September to October (oxidant pollution season). Calibration tests were conducted in supervised

28 outdoor exercise sessions. The exercise sessions consisted of 5 minutes each of rest, slow

29 walking, jogging, and fast walking. HR and VR were measured during the last 2 minutes of each

30 exercise. Individual VR and HR relationships for each individual were determined by fitting a

31 regression line to HR values and log VR values. Each subject recorded their daily activities,
7-3

1 change in location, and breathing rates in diaries for 3 consecutive days. Self-estimated

2 breathing rates were recorded as slow (slow walking), medium (walking faster than normal), and

3 fast (running). HR was recorded once per minute during the 3 days using a Heart Watch. 

4 VR values for each self-estimated breathing rate and activity type were estimated from the

5 HR recordings by employing the VR and HR equation obtained from the calibration tests. 

6 The data presented in Table 7-3 represent HR distribution patterns and corresponding

7 predicted VR for each age group during hours spent awake. At the same self-reported activity

8 levels for both age groups, inhalation rates were higher for outdoor activities than for indoor

9 activities. The total number of hours spent indoors was higher for high school students

10 (21.2 hours) than for elementary school students (19.6 hours). The converse was true for

11 outdoor activities: 2.7 hours for high school students and 4.4 hours for elementary school

12 students (Table 7-4). Based on the data presented in Tables 7-3 and 7-4, the average activity13 specific inhalation rates for elementary school students (10-12 years old) and high school

14 students (13-17 years old) were calculated and are presented in Table 7-5. For elementary

15 school students, the average daily inhalation rates (based on indoor and outdoor locations) are

15.8 m3

/day for light activities, 4.6 m3/day for moderate activities, and 1.0 m3 16 /day for heavy

17 activities. For high school students the daily inhalation rates for light, moderate, and heavy

activities are estimated to be 16.4 m3

/day, 3.0 m3/day, and 0.6 m3 18 /day, respectively (Table 7-5). 

19 A limitation of this study is the small sample size. The results may not be representative

20 of all children in these age groups. Another limitation is that the accuracy of the self-estimated

21 breathing rates reported by younger age groups is uncertain. This may affect the validity of the

22 data set generated. An advantage of this study is that inhalation rates were determined for

23 children and adolescents. These data are useful in estimating exposure for the younger

24 population.

25

26 7.2.3 Adams, 1993

27 Adams (1993) conducted research to accomplish two main objectives: (1) identification

28 of mean and ranges of inhalation rates for various age/gender cohorts and specific activities, and

29 (2) derivation of simple linear and multiple regression equations that could be used to predict

30 inhalation rates through other measured variables: breathing frequency and oxygen consumption. 

31 A total of 160 subjects participated in the primary study. For children, there were two age-
7-4

BSA Height(0.425) Weight(0.425) =× × 71.84 (7-1)

1 dependent groups: children 6 to 12.9 years old and adolescents 13 to18.9 years old. An

2 additional 40 children from 6 to 12 years old and 12 young children from 3 to 5 years old were

3 identified as subjects for pilot testing purposes.

4 Resting protocols conducted in the laboratory for all age groups consisted of three phases

5 (25 minutes each) of lying, sitting, and standing. The phases were categorized as resting and

6 sedentary activities. Two active protocols— moderate (walking) and heavy (jogging/ running)

7 phases— were performed on a treadmill over a progressive continuum of intensity levels made

8 up of 6-minute intervals at three speeds ranging from slow to moderately fast. All protocols

9 involved measuring ventilation rate (VR), heart rate (HR), breathing frequency, and oxygen

10 consumption. Measurements were taken in the last 5 minutes of each phase of the resting

11 protocol and the last 3 minutes of the 6-minute intervals at each speed designated in the active

12 protocols.

13 In the field, all children completed spontaneous play protocols; the older adolescent

14 population (16-18 years) completed car driving and riding, car maintenance (males), and

15 housework (females) protocols. 

16 During all activities in either the laboratory or field protocols, VR for the children’s

17 group revealed no significant gender differences. Therefore, VR data presented in Appendix

18 Tables 7A-1 and 7A-2 were categorized by activity type (lying, sitting, standing, walking, and

19 running) for young children and children without regard to gender. These categorized data from

20 the appendix tables are summarized as inhalation rates in Tables 7-6 and 7-7. The laboratory

21 protocols are shown in Table 7-6. Table 7-7 presents the mean inhalation rates by group and for

22 moderate activity levels in field protocols. Data were not provided for the light and sedentary

23 activities because the group did not perform for this protocol or the number of subjects was too

24 small for appropriate comparisons. Accurate predictions of inhalation rates across all population

25 groups and activity types were obtained by including body surface area (BSA), HR, and

26 breathing frequency in multiple regression analysis (Adams, 1993). Adams (1993) calculated

27 BSA from measured height and weight using the equation:

28

29
7-5

1 A limitation associated with this study is that the population does not represent the

2 general U.S. population. Also, the classification of activity types (i.e., laboratory and field

3 protocols) into activity levels may bias the inhalation rates obtained for various age/gender

4 cohorts. The estimated rates were based on short-term data and may not reflect long-term

5 patterns.

6

7 7.2.4 Layton, 1993

8 Layton (1993) presented a new method for estimating metabolically consistent inhalation

9 rates for use in quantitative dose assessments of airborne radionuclides. Generally, the approach

10 for estimating the breathing rate for a specified time frame was to calculate a time-weighted11 average of ventilation rates associated with physical activities of varying durations. However, in

12 this study, breathing rates were calculated on the basis of oxygen consumption associated with

13 energy expenditures for short (hours) and long (weeks and months) periods of time, using the

14 following general equation to calculate energy-dependent inhalation rates:

15

16 VE E H VQ = ×× (7-2)

17 where:

VE = ventilation rate (L/min or m3 18 /hr);

19 E = energy expenditure rate; [kilojoules/minute (KJ/min) or

20 megajoules/hour (MJ/hr)];

21 H = volume of oxygen [at standard temperature and pressure, dry air

22 consumed in the production of 1 KJ of energy expended (L/KJ or

m3 23 /MJ)]; and

24 VQ = ventilatory equivalent (ratio of minute volume (L/min) to oxygen

25 uptake (L/min)); unitless.

26

27 Layton used two alternative approaches to estimate daily chronic (long term) inhalation

28 rates for different age/gender cohorts of the U.S. population using this methodology.

29
7-6

1 7.2.4.1. First Approach

2 Inhalation rates were estimated by multiplying average daily food energy intakes for

3 different age/gender cohorts, volume of oxygen (H), and ventilatory equivalent (VQ), as shown

4 in the equation above. The average food energy intake data (Table 7-8) are based on

5 approximately 30,000 individuals and were obtained from the USDA 1977-78 Nationwide Food

6 Consumption Survey (USDA-NFCS). The food energy intakes were adjusted upwards by a

7 constant factor of 1.2 for all individuals 9 years and older. This factor compensated for a

8 consistent bias in USDA-NFCS that was attributed to under-reporting of the foods consumed or

9 the methods used to ascertain dietary intakes. Layton used a weighted average oxygen uptake of

0.05 L O2 10 /KJ which was determined from data reported in the 1977-78 USDA-NFCS and the

11 second National Health and Nutrition Examination Survey (NHANES II). The survey sample

12 for NHANES II was approximately 20,000 participants. A VQ of 27 used in the calculations

13 was calculated as the geometric mean of VQ data that were obtained from several studies.

14 The inhalation rate estimation techniques are shown in footnote (a) of Table 7-9. 

15 Table 7-9 presents the daily inhalation rate for each age/gender cohort. The highest daily

inhalation rates were 10 m3

/day for children between the ages of 6 and 8 years, 17 m3 16 /day for

males between 15 and 18 years, and 13 m3 17 /day for females between 9 and 11 years. Inhalation

18 rates were also calculated for active and inactive periods for the various age/gender cohorts.

19 The inhalation rate for inactive periods was estimated by multiplying the basal metabolic

20 rate (BMR) times H times VQ. BMR was defined as "the minimum amount of energy required

21 to support basic cellular respiration while at rest and not actively digesting food" (Layton, 1993). 

22 The inhalation rate for active periods was calculated by multiplying the inactive inhalation rate

23 by the ratio of the rate of energy expenditure during active hours to the estimated BMR. This

24 ratio is presented as F in Table 7-9. These data for active and inactive inhalation rates are also

25 presented in Table 7-9. For children, inactive and active inhalation rates ranged between 2.35

and 5.95 m3

/day and 6.35 to 13.09 m3 26 /day, respectively.

27

28 7.2.4.2. Second Approach

29 Inhalation rates were calculated as the product of the BMR of the population cohorts, the

30 ratio of total daily energy expenditure to daily BMR, H, and VQ. The BMR data obtained from

31 the literature were statistically analyzed, and regression equations were developed to predict
7-7

1 BMR from body weights of various age/gender cohorts. The statistical data used to develop the

2 regression equations are presented in Appendix Table 7A-3. The data obtained from the second

3 approach are presented in Table 7-10. Inhalation rates for children (6 months - 10 years) ranged

from 7.3 to 9.3 m3/day for male and 5.6 to 8.6 m3 4 /day for female children; for older children (10

to 18 years), inhalation rates were 15 m3/day for males and 12 m3 5 /day for females. These rates

6 are similar to the daily inhalation rates obtained using the first approach. Also, the inactive

7 inhalation rates obtained from the first approach are lower than the inhalation rates obtained

8 using the second approach. This may be attributed to the BMR multiplier employed in the

9 equation of the second approach to calculate inhalation rates.

10 Inhalation rates were also obtained for short-term exposures for various age/gender

11 cohorts and five energy-expenditure categories (rest, sedentary, light, moderate, and heavy). 

12 BMRs were multiplied by the product of the metabolic equivalent, H, and VQ. The data

13 obtained for short term exposures are presented in Table 7-11.

14 This study obtains similar results using three different approaches. The major strengths

15 of this study are that it estimates inhalation rates in different age groups and that the populations

16 are large. Explanations for differences in results due to metabolic measurements, reported diet,

17 or activity patterns are supported by observations reported by other investigators in other studies. 

18 Major limitations of this study are (1) the estimated activity pattern levels are somewhat

19 subjective; (2) the explanation that activity pattern differences are responsible for the lower level

20 obtained with the metabolic approach (25 %) compared to the activity pattern approach is not

21 well supported by the data; and (3) different populations were used in each approach, which may

22 have introduced error.

23

24 7.2.5 Rusconi et al., 1994

25 Rusconi et al. (1994) examined a large number of infants and children in order to

26 determine the reference values for respiratory rate in children aged 15 days to 3 years. Previous

27 discrepancies in methodologies and results, and lack of age-related reference values for the first

28 years of life prompted the investigators to obtain normal reference values for respiratory rate

29 from a sufficient number of subjects. They assessed 618 infants and children (336 males and

30 282 females) aged 15 days to 3 years old who did not have respiratory infections or any severe
7-8

1 disease. Of the 618, a total of 309 were in good health and in day care centers, while the

2 remaining 309 were seen in hospitals or outpatients. 

3 Respiratory rates were recorded twice, 30 to 60 minutes apart, listening to breath sounds

4 for 60 seconds with a stethoscope, when the child was awake and calm and when the child was

5 sleeping quietly (sleep not associated with any spontaneous movement, including eye

6 movements or vocalizations) (Table 7-12). The children were assessed for one year in order to

7 determine the repeatability of the recordings, to compare respiratory rate counts obtained by

8 stethoscope and by observation, and to construct reference percentile curves by age in a large

9 number of subjects. 

10 The authors plotted the differences between respiratory rate counts determined by

11 stethoscope at 30- to 60-minute intervals against their mean count in waking and sleeping

12 subjects. The standard deviation of the differences between the two counts was 2.5 and 1.7

13 breaths/minute, respectively, for waking and sleeping children. This standard deviation yielded

14 95% repeatability coefficients of 4.9 breaths when the infants and children were awake and 3.3

15 breaths when they were asleep.

16 In both waking and sleeping states, the respiratory rate counts determined by stethoscope

17 were found to be higher than those obtained by observation. The mean difference was 2.6 and

18 1.8 breaths per minute, respectively, in waking and sleeping states. The mean respiratory rate

19 counts were significantly higher in infants and children at all ages when awake and calm than

20 when asleep. A decrease in respiratory rate with increasing age was seen in waking and sleeping

21 infants and children. A scatter diagram of respiratory rate counts by age in waking and sleeping

22 subjects showed that the pattern of respiratory rate decline with age was similar in both states,

23 but it was much faster in the first few months of life. The authors constructed centile curves by

24 first log-transforming the data and then applying a second degree polynormal curve, which

25 allowed excellent fitting to observed data. Figures 7-1 and 7-2 show smoothed percentiles by

26 age in waking and sleeping subjects, respectively.

27 The authors suggested that the differences between the reported respiratory rates in

28 healthy infants and children might be due to various factors, including the number of infants

29 studied, the period of time of counting, the method of counting, and the state of the infant. The

30 variability of respiratory rate among subjects was higher in the first few months of life, which

31 may be attributable to biological events that occur during these months, such as maturation of the
7-9

1 neurologic control of breathing and changes in lung and chest wall compliance and lung

2 volumes.

3 An advantage of this study is that it provides distribution data for respiratory rate for

4 children from infancy (less than 2 months) to 36 months old. These data are not U.S. data;

5 however, U.S. distributions were not available.

6

7 7.2.6 Lordo et al., 2006

8 Lordo et al. (2006), under direction from EPA’s National Center for Environmental

9 Assessment (NCEA), conducted a study to ascertain ventilation rates for children and adults.

10 Specifically, they sought to improve upon the methodology used by Layton (1993) and other

11 studies that relied upon the ventilatory equivalent (VQ) and a linear relationship between oxygen

12 consumption and fitness rate. The authors used a revised approach, developed by EPA’s

13 National Exposure Research Laboratory (NERL), in which an individual’s ventilation rate is

14 derived from his or her oxygen consumption rate. Lordo et al. apply this revised approach using

15 weight data from the 1999-2002 NHANES and metabolic equivalents (METS) data from EPA’s

16 Consolidated Human Activity Database (CHAD).

17 NHANES provided age, gender, and body weight data for 19,022 individuals from

18 throughout the United States. From these data, basal metabolic rate (BMR) was estimated using

19 an age-specific linear equation used in Appendix 5A the Exposure Factors Handbook (EPA,

20 1997), and in several other studies and reference works. 

21 The CHAD database is a compilation of several databases of human activity patterns.

22 Lordo et al. used one of these studies, the National Human Activity Pattern Survey (NHAPS), as

23 its source for METS values because it was more representative of the entire United States

24 population than the other studies in the database. The NHAPS data set included activity data for

25 9,196 individuals, each of which provided 24 hours of activity pattern data using a diary-based

26 questionnaire. While NHAPS was identified as the best available data source for activity

27 patterns, there were some shortcomings in the quality of the data. Study respondents did not

28 provide body weights; instead, body weights are simulated using statistical sampling. Also, the

29 NHAPS data extracted from CHAD could not be corrected to account for non-random sampling

30 of study participants and survey days.
7-10

1 NHANES and NHAPS data were grouped into age categories using the standardized age

2 categories presented elsewhere in this Handbook, with the exception that children under the age

3 of one year were placed into a single category to preserve an adequate sample size within the

4 category. For each NHANES participant, a “simulated” 24-hour activity pattern was generated

5 by randomly sampling activity patterns from the set of NHAPS participants with the same

6 gender and age category as the NHANES participant. Twenty such patterns were selected at

7 random for each NHANES participant, resulting in 480 hours of simulated activity data for each

8 NHANES participant. The data were then scaled down to a 24-hour time frame to yield an

9 average 24-hour activity pattern for each of the 19,022 NHANES individuals.

10 Each activity was assigned a METS value based on statistical sampling of the statistical

11 distribution assigned by CHAD to each activity code. For most codes, these distributions were

12 not age-dependent, but age was a factor for some activities for which intensity level varies

13 strongly with age. Using statistical software, equations for METS based on normal, lognormal,

14 exponential, triangular, and uniform distributions were generated as needed for the various

15 activity codes. The METS values were then translated into energy expenditure (EE) by

16 multiplying the METS by the basal metabolic rate (BMR), which was calculated as a linear

function of body weight. The oxygen consumption rate VO2 17 was calculated by multiplying EE by

H, the volume of oxygen consumed per unit of energy. VO2 18 was calculated both as volume per

19 time and as volume per time per unit body weight.

20 The ventilation rate for each activity within the 24-hour simulated activity pattern for

each individual was estimated as a function of VO2 21 , body weight, age, and gender. Following

22 this, average ventilation rate was calculated for each individual for the entire 24-hour period, as

23 well as for four separate classes of activities based on METS value (sedentary/passive (METS

24 less than or equal to 1.5), light intensity (METS greater than 1.5 and less than or equal to 3.0),

25 moderate intensity (METS greater than 3.0 and less than or equal to 6.0), and high intensity

26 (METS greater than 6.0)). Data for individuals were then used to generate summary tables based

27 on gender and age categories.

28 Data from this study are presented in Tables 7-13 through 7-19. Tables 7-13 and 7-14

29 present, for male and female subjects respectively, summary statistics for daily average

30 ventilation rate by age category on a volumetric (L/min) and weight adjusted (L/min-kg) basis.

31 Tables 7-15 and 7-16 present, for male and female subjects respectively, mean ventilation rates
7-11

1 by age category on a volumetric (L/min) and weight adjusted (L/min-kg) basis for the five

2 different activity level ranges described above. They also present the daily ventilation rates

3 (L/day and L/day-kg) for each activity level and age group and the mean number of hours spent

4 engaged in each of these activities by subjects in each age group.

5 Tables 7-17 and 7-18 present the same data as Tables 7-13 and 7-14, respectively, but in

units of m3

/day and m3 6 /day-kg rather than L/min and L/min-kg. Table 7-19 presents the number

7 of hours spent at each activity level by males and females; the data are similar to the activity data

8 presented in Tables 7-15 and 7-16 but offer percentile data in addition to the mean.

9

10 7.3 RECOMMENDATIONS

11 The recommended inhalation rates for children are based on the EPA-sponsored research

12 of Lordo et al. (2006), which is the most recent and geographically broad of the studies described

13 in this chapter. The study represents an improvement upon studies previously used for

14 recommended inhalation rates in this Handbook in that it uses a large data set that is

15 representative of the United States as a whole and considers the correlation between body weight

16 and inhalation rate. The confidence level for the studies considered in this chapter are presented

17 in Table 7-20.

18 Table 7-21 summarizes the short-and long-term inhalation rates for the standard age

19 categories used in this Handbook.
7-12

1 7.4 REFERENCES FOR CHAPTER 7

2

3 Adams, W.C. (1993) Measurement of breathing rate and volume in routinely performed daily activities, Final

4 Report. California Air Resources Board (CARB) Contract No. A033-205. June 1993. 185 pgs. 

5

6 Basiotis, P.P.; Thomas, R.G.; Kelsay, J.L.; Mertz, W. (1989) Sources of variation in energy intake by men and

7 women as determined from one year’s daily dietary records. Am. J. Clin. Nutr. 50:448-453.

8

9 Layton, D.W. (1993) Metabolically consistent breathing rates for use in dose assessments. Health Physics 64(1):23-

10 36.

11

12 Linn, W.S.; Shamoo, D.A.; Hackney, J.D. (1992) Documentation of activity patterns in "high-risk" groups exposed

13 to ozone in the Los Angeles area. In: Proceedings of the Second EPA/AWMA Conference on Tropospheric

14 Ozone, Atlanta, Nov. 1991. pp. 701-712. Air and Waste Management Assoc., Pittsburgh, PA. 

15

16 Lordo, B.; Sanford, J.; Mohnson, M. (2006) Revision of the Metabolically-Derived Ventilation Rates Within the

17 Exposure Factors Handbook. Battelle Institute, Columbus, OH. Prepared for USEPA/ORD, Contract No.

18 EP-C-04-027.

19

20 Rusconi, F.; Castagneto, M.; Garliardi, L.; Leo, G.; Pellegatta, A.; Porta, N.; Razon, S.; Braga, M. (1994) Reference

21 values for respiratory rate in the first 3 years of life. Pediatrics 94(3):350-5. September 1994.

22

23 Spier, C.E.; Little, D.E.; Trim, S.C.; Johnson, T.R.; Linn, W.S.; Hackney, J.D. (1992) Activity patterns in

24 elementary and high school students exposed to oxidant pollution. J. Exp. Anal. Environ. Epid. 2(3):277-

25 293.

26

27 WHO (1986) Principles for evaluating health risks from chemicals during infancy and early childhood: the need for

28 a special approach. Environmental Health Criteria 59, World Health Organization, International

29 Programme on Chemical Safety.

30

31

32
7-13

Table 7-1. Calibration And Field Protocols For Self-monitoring of Activities Grouped by Subject Panels

Panel Calibration Protocol Field Protocol

Panel 2 - Healthy Elementary

School Students - 5 male,

12 female, age 10-12

Outdoor exercises each consisted of

20 minute rest, slow walking,

jogging and fast walking

Saturday, Sunday and Monday (school

day) in early autumn; HR recordings

and activity diary during waking hours

and during sleep.

Panel 3 - Healthy High School

Students - 7 male, 12 female,

age 13-17

Outdoor exercises each consisted of

20 minute rest, slow walking,

jogging and fast walking

Same as Panel 2, however, no HR

recordings during sleep for most

subjects.

Panel 6 - Young Asthmatics - 7

male, 6 female, age 11-16

Laboratory exercise tests on bicycles

and treadmills

Summer monitoring for 2 successive

weeks, including 2 controlled exposure

studies with few or no observable

respiratory effects.

Source: Linn et al., 1992

Table 7-2. Subject Panel Inhalation Rates by Mean VR, Upper Percentiles, And Self-estimated Breathing Rates

Inhalation Rates (m3

/hr)

Na Mean VR

(m3/hr)

99th

Percentile VR

Mean VR at Activity Levels

(m3/hr)b

Panel Slow Medium Fast

Healthy

 2 - Elementary School Students

 3 - High School Students

17

19

0.90

0.84

1.98

2.22

0.84

0.78

0.96

1.14

1.14

1.62

Asthmatics

 6 - Elementary and High School

 Students

13 1.20 2.40 1.20 1.20 1.50

a

Number of individuals in each survey panel.

b

Some subjects did not report medium and/or fast activity. Group means were calculated from individual means

 (i.e., give equal weight to each individual who recorded any time at the indicated activity level).

Source: Linn et al., 1992
7-14

Table 7-3. Distribution of Predicted Intake Rates by Location And Activity Levels For Elementary And High

School Students

Inhalation Rates (m3/hr)

Percentile Rankingsb

Age (yrs) Student Location

Activity

Level

%

Recorded

Timea

Mean ± SD 1st 50th 99.9th

10-12 Elc

(nd=17)

Indoors slow

medium

fast

49.6

23.6

2.4

0.84 ± 0.36

0.96 ± 0.36

1.02 ± 0.60

0.18

0.24

0.24

0.78

0.84

0.84

2.34

2.58

3.42

Outdoors slow

medium

fast

8.9

11.2

4.3

0.96 ± 0.54

1.08 ± 0.48

1.14 ± 0.60

0.36

0.24

0.48

0.78

0.96

0.96

4.32

3.36

3.60

13-17 HSc

(nd=19)

Indoors slow

medium

fast

70.7

10.9

1.4

0.78 ± 0.36

0.96 ± 0.42

1.26 ± 0.66

0.30

0.42

0.54

0.72

0.84

1.08

3.24

4.02

6.84c

Outdoors slow

medium

fast

8.2

7.4

1.4

0.96 ± 0.48

1.26 ± 0.78

1.44 ± 1.08

0.42

0.48

0.48

0.90

1.08

1.02

5.28

5.70

5.94

a

Recorded time averaged about 23 hr per elementary school student and 33 hr. per high school student, 

 over 72-hr. periods.

b

Geometric means closely approximated 50th percentiles; geometric standard deviations were 1.2-1.3 for HR,

 1.5-1.8 for VR.

c

EL = elementary school student; HS = high school student.

d

N = number of students that participated in survey.

e

Highest single value.

Source: Spier et al., 1992

Table 7-4. Average Hours Spent Per Day in a Given Location and Activity Level For Elementary and High

School Students

Students

Location

Activity Level Total Time Spent

(hrs/day)

Slow Medium Fast

Elementary school,

ages 10-12 years

(N=17)

Indoors 16.3 2.9 0.4 19.6

Outdoors 2.2 1.7 0.5 4.4

High school, 

ages 13-17 years

(N=19)

Indoors 19.5 1.5 0.2 21.2

Outdoors 1.2 1.3 0.2 2.7

Source: Spier et al., 1992

Table 7-5. Distribution Patterns of Daily Inhalation Rates For Elementary (EL) And High School (HS) Students

Grouped by Activity Levela
7-15

Students Location Activity typeb

Mean IRc

(m3/day)

Percentile Rankings

1st 50th 99.9th

Elementary school,

ages 10-12 years

(N=17)

Indoors Light

Moderate

Heavy

13.7

2.8

0.4

2.9

0.7

0.1

12.7

2.4

0.3

38.1

7.5

1.4

Outdoors Light

Moderate

Heavy

2.1

1.8

0.6

0.8

0.4

0.2

1.7

1.6

0.5

9.5

5.7

1.8

High school, 

ages 13-17 years

(N=19)

Indoors Light

Moderate

Heavy

15.2

1.4

0.3

5.9

0.6

0.1

14.0

1.3

0.2

63.2

6.0

1.4

Outdoors Light

Moderate

Heavy

1.2

1.6

0.3

0.5

0.6

0.1

1.1

1.4

0.2

6.3

7.4

1.2

a Generated using data from Tables 7-3 and 7-4

b

 For this report, activity type presented in Table 7-2 was redefined as light activity for slow, moderate activity

 for medium, and heavy activity for fast.

c Daily inhalation rate (IR) was calculated by multiplying the hours spent at each activity level (Table 7-4) by the

 corresponding inhalation rate (Table 7-3).

Source: Adapted from Spier et al., 1992
7-16

Table 7-6. Summary of Average Inhalation Rates (m3/hr) by Age Group And Activity Levels for Laboratory

Protocols

Age Group Activity Level

Restinga Sedentaryb Lightc Moderated Heavye

Young Children

(3-5.9 years)

Average inhalation rate (m3/hr)

(N=12, gender not specified)

0.37 0.40 0.65 DNPf DNPf

Children

(6-12.9 years)

Average inhalation rate (m3/hr)

(N=40, 20 male and 20 female)

0.45 0.47 0.95 1.74 2.23

a

Resting defined as lying (see Appendix Table 7A-1 for original data).

b

Sedentary defined as sitting and standing (see Appendix Table 7A-1 for original data). c

Light defined as walking at speed level 1.5 - 3.0 mph (see Appendix Table 7A-1 for original data). d

Moderate defined as fast walking (3.3 - 4.0 mph) and slow running (3.5 - 4.0 mph) (see Appendix Table 7A-1

 for original data).

e

Heavy defined as fast running (4.5 - 6.0 mph) (see Appendix Table 7A-1 for original data). f

DNP. Group did not perform this protocol or N was too small for appropriate mean comparisons. All young

 children did not run.

Source: Adapted from Adams, 1993
7-17

Table 7-7. Summary of Average Inhalation Rates (m3/hr) by Age Group And Activity Levels in Field Protocols

Age Group Moderate Activitya

Young Children (3-5.9 years)

Average inhalation rate (m3/hr)

(N=12, gender not specified)

0.68

Children (6-12.9 years)

Average inhalation rate (m3/hr)

(N=40, 20 male and 20 female)

1.07

a Moderate activity was defined as mowing (males); wood working (males); yard work (males); and play 

(children) (see Appendix Table 7A-2 for original data).

Source: Adams, 1993.
7-18

Table 7-8. Comparisons of Estimated Basal Metabolic Rates (BMR) With Average Food-energy Intakes (EFD)

For Individuals Sampled in The 1977-78 NFCS

Cohort/Age

(years)

Body Weight

kg

BMRa Energy Intake (EFD)

Ratio

EFD/BMR

MJ d-1 kcal d-1 MJ d-1 kcal d-1

Children

 < 1 7.6 1.74 416 3.32 793 1.90

 1 to 2 13 3.08 734 5.07 1209 1.65

 3 to 5 18 3.69 881 6.14 1466 1.66

 6 to 8 26 4.41 1053 7.43 1774 1.68

Males

 9 to 11 36 5.42 1293 8.55 2040 1.58

 12 to 14 50 6.45 1540 9.54 2276 1.48

 15 to 18 66 7.64 1823 10.8 2568 1.41

Females

 9 to 11 36 4.91 1173 7.75 1849 1.58

 12 to 14 49 5.64 1347 7.72 1842 1.37

 15 to 18 56 6.03 1440 7.32 1748 1.21

a

Calculated from the appropriate age and gender-based BMR equations given in Appendix Table 7A-3.

MJ d-1 - mega joules/day

kcal d-1 - kilo calories/day

EFD= Food energy intake (Kcal/day) or (MJ/day)

Source: Layton, 1993
7-19

Table 7-9. Daily Inhalation Rates Calculated From Food-energy Intakes

Cohort/Age

(years) L

Daily Inhalation Ratea

(m3/day)

Sleep

(hours)

MET Value Inhalation Rates

Ab Fc Inactived

(m3/day)

Activee

(m3/day)

Children

<1

1 - 2

3 - 5

6 - 8

1

2

3

3

4.5

6.8

8.3

10

11

11

10

10

1.9

1.6

1.7

1.7

2.7

2.2

2.2

2.2

2.35

4.16

4.98

5.95

6.35

9.15

10.96

13.09

Males

9 - 11

12 - 14

15 - 18

3

3

4

14

15

17

9

9

8

1.9

1.8

1.7

2.5

2.2

2.1

7.32

8.71

10.31

18.3

19.16

21.65

Females

9 - 11

12 - 14

15 - 18

3

3

4

13

12

12

9

9

8

1.9

1.6

1.5

2.5

2.0

1.7

6.63

7.61

8.14

16.58

15.22

13.84

a

Daily inhalation rate was calculated by multiplying the EFD values (see Table 7-8) by H × VQ for subjects under

9 years of age and by 1.2 × H × VQ (for subjects 9 years of age and older (see text for explanation), where EFD

= Food energy intake (Kcal/day) or (MJ/day), H = Oxygen uptake = 0.05 LO2/KJ or 0.21 LO2/Kcal, and 

VQ = Ventilation equivalent = 27 = geometric mean of VQs (unitless).

b

For individuals 9 years of age and older, A was calculated by multiplying the ratio for EFD/BMR (unitless)

 (Table 7-8) by the factor 1.2 (see text for explanation).

c

F = (24 × A - S)/(24 - S) (unitless), ratio of the rate of energy expenditure during active hours to the estimated

 BMR (unitless), where S = Number of hours spent sleeping each day. d

Inhalation rate for inactive periods was calculated as BMR × H × VQ, and for active periods by multiplying the

inactive inhalation rate by F (see footnote c); BMR values are from Table 7-8, where BMR = basal metabolic rate

(MJ/day) or (kg/hr).

L = number of years for each age cohort.

MET = metabolic equivalent.

Source: Layton, 1993
7-20

Table 7-10. Daily Inhalation Rates Obtained From The Ratios Of Total Energy Expenditure to Basal Metabolic

Rate (BMR)

Gender/Age

(yrs)

Body Weighta

(kg)

BMRb

(MJ/day) VQ Ac

H

(m3

O2/MJ)

Inhalation Rate, VE

(m3/day)d

Male

0.5 - <3

3 - <10

10 - <18

14

23

53

3.4

4.3

6.7

27

27

27

1.6

1.6

1.7

0.05

0.05

0.05

7.3

9.3

15

Female

0.5 - <3

3 - <10

10 - <18

11

23

50

2.6

4.0

5.7

27

27

27

1.6

1.6

1.5

0.05

0.05

0.05

5.6

8.6

12

a

Body weight was based on the average weights for age/gender cohorts in the U.S. population.

b

The BMRs (basal metabolic rate) are calculated using the respective body weights and BMR equations (see

 Appendix Table 7A-3).

c

The values of the BMR multiplier (EFD/BMR) for those 18 years and older were derived from the Basiotis

 et al. (1989) study: Male = 1.59, Female = 1.38. For males and females under 10 years old, the mean BMR

 multiplier used was 1.6. For males and females aged 10 to < 18 years, the mean values for A given in 

 Table 7-9 for 12-14 years and 15-18 years, age brackets for males and females were used: male = 1.7 and

 female = 1.5.

d

Inhalation rate = BMR x A x H x VQ; VQ = ventilation equivalent and H = oxygen uptake.

Source: Layton, 1993
7-21

Table 7-11. Inhalation Rates For Short-term Exposures

Gender/Age

(yrs)

Weight

(kg)a BMRb

(MJ/day)

Activity Type

Rest Sedentary Light Moderate Heavy

MET (BMR Multiplier)

1 1.2 2c 4d 10e

Inhalation Rate (m3/hr)f,g

Male

 0.5 - <3

 3 - <10

 10 - <18

Female

 0.5 - <3

 3 - <10

 10 - <18

14

23

53

11

23

50

3.40

4.30

6.70

2.60

4.00

5.70

0.19

0.24

0.38

0.14

0.23

0.32

0.23

0.29

0.45

0.17

0.27

0.38

0.38

0.49

0.78

0.29

0.45

0.66

0.78

0.96

1.50

0.60

0.90

1.26

1.92

2.40

3.78

1.44

2.28

3.18

a

Body weights were based on average weights for age/gender cohorts of the U.S. population b

The BMRs for the age/gender cohorts were calculated using the respective body weights and the BMR

 equations (Appendix Table 7A-3).

c

Range = 1.5 - 2.5.

d

Range = 3 - 5.

e

Range = >5 - 20.

f

The inhalation rate was calculated as IR = BMR (MJ/day) × H (0.05 L/KJ) × MET × VQ (27) × (d/24 hrs) g

Original data were presented in L/min. Conversion to m3/hr was obtained as follows: 60 min

hr

m

1000L

L

min

1

× ×

Source: Layton, 1993
7-22

Table 7-12. Mean, Median, and SD of Respiratory Rate According to Waking or Sleeping in 618 Infants and

Children Grouped in Classes of Age

Age (months) N

Respiratory Rate (breaths/min)

Waking Sleeping

Mean ± SD Median Mean ± SD Median

<2 104 48.0 ± 9.1 47 39.8 ± 8.7 39

2 to <6 106 44.1 ± 9.9 42 33.4 ± 7.0 32

6 to <12 126 39.1 ± 8.5 38 29.6 ± 7.0 28

12 to <18 77 34.5 ± 5.8 34 27.2 ± 5.6 26

18 to <24 65 32.0 ± 4.8 32 25.3 ± 4.6 24

24 to <30 79 30.0 ± 6.2 30 23.1 ± 4.6 23

30 to 36 61 27.1 ± 4.1 28 21.5 ± 3.7 21

Source: Rusconi et al., 1994
7-23

Figure 7-1. 5th, 10th, 25th, 50th, 75th, 90th, and 95th Smoothed Centiles by Age in Awake Subjects

(RR = respiratory rate). Source: Rusconi et al., 1994

Figure 7-2. 5th, 10th, 25th, 50th, 75th, 90th, and 95th Smoothed Centiles by Age in Asleep Subjects

(RR = respiratory rate). Source: Rusconi et al., 1994
7-24

Table 7-13. Descriptive Statistics for Daily Average Ventilation Rate (L/min) in Males, by Age Category

Age Category N

Daily Average Ventilation Rate, Unadjusted for Body Weight 

( ; L/min) V&E

Daily Average Ventilation Rate, Adju

(V&/BW: L/min-k

E

Mean

Percentiles Maximum Mean Percentiles 

5th 10th 25th 50th 75th 90th 95th 5th 10th 25th 50th 75

Birth to <1 year 419 6.08 3.32 3.96 4.97 6.04 7.24 8.28 8.81 11.84 0.759 0.634 0.655 0.696 0.754 0.8

1 year 308 9.37 6.76 7.23 8.09 9.11 10.43 11.82 12.43 16.83 0.823 0.669 0.706 0.756 0.813 0.8

2 years 261 9.19 6.56 7.09 7.94 9.16 10.07 11.30 12.30 19.56 0.658 0.542 0.567 0.606 0.655 0.7

3 to <6 years 540 8.78 7.24 7.55 7.91 8.74 9.47 10.16 10.70 13.56 0.488 0.363 0.386 0.426 0.481 0.5

6 to <11 years 940 9.32 7.00 7.42 8.15 9.09 10.23 11.50 12.31 17.34 0.307 0.221 0.238 0.261 0.302 0.3

11 to <16 years 1337 10.64 7.92 8.41 9.22 10.27 11.68 13.57 14.73 19.82 0.198 0.144 0.153 0.171 0.192 0.216 to <21 years 1241 11.95 8.75 9.31 10.06 11.55 13.31 15.23 16.23 27.23 0.159 0.116 0.126 0.140 0.158 0.1

Individual daily averages are weighted by their 4-year sampling weights as assigned within NHANES 1999-2002 when calculating the statistics in thi

estimated using a multiple linear regression model.

Source: Lordo et al., 2006
7-25

Table 7-14. Descriptive Statistics for Daily Average Ventilation Rate (L/min) in Females, by Age Category

Age Category N

Daily Average Ventilation Rate, Unadjusted for Body Weight 

( ; L/min) V&E

Daily Average Ventilation Rate, Adju

 (V&/BW: L/min-k

E

Mean

Percentiles Maximum Mean Percentiles 

5th 10th 25th 50th 75th 90th 95th 5th 10th 25th 50th 75

Birth to <1 year 415 5.92 3.36 3.81 4.75 5.84 6.79 8.09 8.79 18.23 0.793 0.634 0.673 0.720 0.782 0.8

1 year 245 9.24 6.31 7.03 7.81 9.05 10.17 12.12 12.93 17.20 0.831 0.677 0.703 0.765 0.818 0.9

2 years 255 8.85 6.19 6.99 7.90 8.75 9.69 10.82 11.36 15.98 0.663 0.569 0.583 0.618 0.664 0.7

3 to <6 years 543 8.45 6.86 7.21 7.78 8.35 9.04 9.74 10.37 13.71 0.480 0.335 0.372 0.414 0.475 0.5

6 to <11 years 894 8.62 6.94 7.19 7.65 8.30 9.32 10.51 11.35 14.46 0.297 0.194 0.214 0.248 0.296 0.3

11 to <16 years 1451 9.33 7.27 7.72 8.36 9.08 10.10 11.29 12.09 18.46 0.174 0.131 0.138 0.153 0.170 0.1

16 to <21 years 1182 9.44 6.85 7.37 8.18 9.17 10.43 11.89 12.70 20.91 0.148 0.110 0.117 0.132 0.144 0.1

Individual daily averages are weighted by their 4-year sampling weights as assigned within NHANES 1999-2002 when calculating the statistics in thi

estimated using a multiple linear regression model.

Source: Lordo et al., 2006
7-26

Table 7-15. Average Time Spent Per Day Performing Activities Within Specified Intensity Categories, and Average

Ventilation Rates Associated With These Activity Categories, for Males According to Age Category

Age Category

# NHANES

Participants

Reporting

Activity

Average

Duration

(hr/day)

Spent at

Activity

Ventilation Rate During This

Activity1

Daily Ventilation Rate Associated

With This Activity2

Unadjusted for

Body Weight

(L/min)

Adjusted for

Body Weight

(L/min-kg)

Unadjusted for

Body Weight

(L/day)

Adjusted for

Body Weight

(L/day-kg)

Sleep or nap (Activity ID = 14500)

Birth to <1 year 419 13.5 3.08 0.385 2,499 311.8

1 year 308 12.6 4.50 0.395 3,405 298.9

2 years 261 12.1 4.61 0.330 3,334 239.1

3 to <6 years 540 11.2 4.36 0.243 2,928 162.9

6 to <11 years 940 10.2 4.61 0.151 2,814 92.5

11 to <16 years 1,337 9.4 5.26 0.098 2,958 54.9

16 to <21 years 1,241 8.7 5.31 0.071 2,769 36.9

21 to <31 years 701 8.4 4.73 0.058 2,368 29.0

31 to <41 years 728 8.1 5.16 0.061 2,496 29.4

41 to <51 years 753 7.9 5.65 0.065 2,676 30.9

51 to <61 years 627 8.0 5.78 0.066 2,757 31.7

61 to <71 years 678 8.3 5.98 0.069 2,979 34.5

71 to <81 years 496 8.5 6.07 0.075 3,098 38.1

81 years and older 255 9.2 5.97 0.080 3,309 44.3

Sedentary & Passive Activities (METS # 1.5 -- Includes Sleep or Nap)

Birth to <1 year 419 15.0 3.18 0.397 2,858 355.9

1 year 308 14.3 4.62 0.406 3,958 347.5

2 years 261 14.6 4.79 0.343 4,206 301.7

3 to <6 years 540 14.1 4.58 0.255 3,886 216.0

6 to <11 years 940 13.5 4.87 0.160 3,949 130.2

11 to <16 years 1,337 13.8 5.64 0.105 4,692 87.1

16 to <21 years 1,241 13.2 5.76 0.077 4,575 61.1

21 to <31 years 701 12.4 5.11 0.062 3,807 46.6

31 to <41 years 728 12.3 5.57 0.066 4,117 48.6

41 to <51 years 753 12.3 6.11 0.071 4,522 52.2

51 to <61 years 627 13.1 6.27 0.072 4,918 56.5

61 to <71 years 678 14.5 6.54 0.076 5,693 66.1

71 to <81 years 496 15.9 6.65 0.082 6,345 78.1

81 years and older 255 16.6 6.44 0.086 6,411 85.9
Age Category

# NHANES

Participants

Reporting

Activity

Average

Duration

(hr/day)

Spent at

Activity

Ventilation Rate During This

Activity1

Daily Ventilation Rate Associated

With This Activity2

Unadjusted for

Body Weight

(L/min)

Adjusted for

Body Weight

(L/min-kg)

Unadjusted for

Body Weight

(L/day)

Adjusted for

Body Weight

(L/day-kg)

7-27

Light Intensity Activities (1.5 < METS # 3.0)

Birth to <1 year 419 5.3 7.94 0.988 2,603 322.7

1 year 308 5.5 11.56 1.019 3,959 350.7

2 years 261 5.5 11.67 0.837 3,917 281.9

3 to <6 years 540 6.6 11.36 0.633 4,561 255.2

6 to <11 years 940 7.6 11.64 0.384 5,345 177.5

11 to <16 years 1,337 7.5 13.22 0.246 5,943 110.9

16 to <21 years 1,241 7.1 13.41 0.179 5,745 76.9

21 to <31 years 701 6.1 12.97 0.158 4,821 58.5

31 to <41 years 728 5.7 13.64 0.161 4,714 55.5

41 to <51 years 753 6.1 14.38 0.166 5,271 60.8

51 to <61 years 627 5.6 14.56 0.167 5,005 57.0

61 to <71 years 678 5.5 14.12 0.164 4,669 54.0

71 to <81 years 496 5.0 13.87 0.171 4,131 50.8

81 years and older 255 4.9 13.76 0.185 4,014 53.9

Moderate Intensity Activities (3.0 < METS # 6.0)

Birth to <1 year 419 3.7 14.49 1.804 3,157 396.5

1 year 308 4.0 21.35 1.878 5,141 451.0

2 years 261 3.8 21.54 1.546 4,958 353.4

3 to <6 years 540 3.2 21.03 1.173 3,890 214.5

6 to <11 years 940 2.7 22.28 0.736 3,567 115.1

11 to <16 years 1,337 2.3 26.40 0.491 3,733 68.8

16 to <21 years 1,241 3.3 29.02 0.387 5,904 78.3

21 to <31 years 701 5.2 29.19 0.357 9,369 115.2

31 to <41 years 728 5.7 30.30 0.357 10,560 124.1

41 to <51 years 753 5.4 31.58 0.366 10,438 121.3

51 to <61 years 627 5.0 32.71 0.376 9,953 115.1

61 to <71 years 678 3.7 29.76 0.344 6,705 77.4

71 to <81 years 496 2.9 29.29 0.360 5,058 62.0

81 years and older 255 2.3 28.53 0.383 4,036 54.1
Age Category

# NHANES

Participants

Reporting

Activity

Average

Duration

(hr/day)

Spent at

Activity

Ventilation Rate During This

Activity1

Daily Ventilation Rate Associated

With This Activity2

Unadjusted for

Body Weight

(L/min)

Adjusted for

Body Weight

(L/min-kg)

Unadjusted for

Body Weight

(L/day)

Adjusted for

Body Weight

(L/day-kg)

7-28

High Intensity (METS > 6.0)

Birth to <1 year 183 0.2 27.47 3.477 325 41.2

1 year 164 0.3 40.25 3.523 799 68.3

2 years 162 0.1 40.45 2.889 242 17.4

3 to <6 years 263 0.3 39.04 2.167 639 34.3

6 to <11 years 637 0.3 43.62 1.410 851 28.2

11 to <16 years 1,111 0.4 50.82 0.950 1,154 21.9

16 to <21 years 968 0.4 53.17 0.711 1,275 16.9

21 to <31 years 546 0.3 53.91 0.660 1,041 12.8

31 to <41 years 567 0.4 54.27 0.644 1,183 14.1

41 to <51 years 487 0.3 57.31 0.655 1,124 12.7

51 to <61 years 452 0.4 58.42 0.675 1,441 16.5

61 to <71 years 490 0.4 54.13 0.624 1,158 13.3

71 to <81 years 343 0.4 52.46 0.646 1,181 14.6

81 years and older 168 0.3 53.31 0.716 1,052 13.9

1

 An individual’s ventilation rate for the given activity category equals the weighted average of the individual’s activity-specific

ventilation rates for activities falling within the category, estimated using a multiple linear regression model, with weights

corresponding to the number of minutes spent performing the activity. Numbers in these two columns represent averages,

calculated across individuals in the specified age category, of these weighted averages. These are weighted averages, with the

weights corresponding to the 4-year sampling weights assigned within NHANES 1999-2002.

2

 An individual’s daily average ventilation rate equals the product of the individual’s weighted average ventilation rate for the

given activity category (L/min), estimated using a multiple linear regression model, and the number of minutes per day that the

individual performs an activity within the category. Numbers in these two columns represent weighted averages across

individuals in the specified age category, with the weights corresponding to the 4-year sampling weights assigned within

NHANES 1999-2002.

Source: Lordo et al., 2006
7-29

Table 7-16. Average Time Spent Per Day Performing Activities Within Specified Intensity Categories, and Average

Ventilation Rates Associated With These Activity Categories, for Females According to Age Category

Age Category

# NHANES

Participants

Reporting

Activity

Average

Duration

(hr/day)

Spent at

Activity

Ventilation Rate During This

Activity1

Daily Ventilation Rate Associated

With This Activity2

Unadjusted for

Body Weight

(L/min)

Adjusted for

Body Weight

(L/min-kg)

Unadjusted for

Body Weight

(L/day)

Adjusted for

Body Weight

(L/day-kg)

Sleep or nap (Activity ID = 14500)

Birth to <1 year 415 13.0 2.92 0.391 2,275 304.9

1 year 245 12.6 4.59 0.414 3,466 313.0

2 years 255 12.1 4.56 0.342 3,307 248.4

3 to <6 years 543 11.1 4.18 0.238 2,788 158.9

6 to <11 years 894 10.3 4.36 0.151 2,686 92.7

11 to <16 years 1,451 9.6 4.81 0.090 2,766 51.6

16 to <21 years 1,182 9.1 4.40 0.069 2,398 37.7

21 to <31 years 1,023 8.6 3.89 0.055 2,009 28.6

31 to <41 years 869 8.3 4.00 0.056 1,996 27.8

41 to <51 years 763 8.3 4.40 0.060 2,197 29.9

51 to <61 years 622 8.1 4.56 0.061 2,222 29.8

61 to <71 years 700 8.4 4.47 0.061 2,255 30.5

71 to <81 years 470 8.6 4.52 0.066 2,325 33.9

81 years and older 306 9.1 4.49 0.072 2,456 39.1

Sedentary & Passive Activities (METS # 1.5 -- Includes Sleep or Nap)

Birth to <1 year 415 14.1 3.00 0.402 2,538 339.4

1 year 245 14.3 4.71 0.425 4,046 365.9

2 years 255 14.9 4.73 0.355 4,215 316.4

3 to <6 years 543 14.3 4.40 0.251 3,773 214.8

6 to <11 years 894 14.0 4.64 0.160 3,898 134.3

11 to <16 years 1,451 14.2 5.21 0.097 4,442 83.1

16 to <21 years 1,182 13.6 4.76 0.075 3,876 61.0

21 to <31 years 1,023 12.6 4.19 0.060 3,164 45.0

31 to <41 years 869 12.3 4.33 0.060 3,197 44.7

41 to <51 years 763 12.2 4.75 0.065 3,489 47.5

51 to <61 years 622 12.7 4.96 0.067 3,771 50.7

61 to <71 years 700 14.3 4.89 0.066 4,183 56.6

71 to <81 years 470 15.4 4.95 0.072 4,569 66.6

81 years and older 306 16.5 4.89 0.078 4,841 77.3
Table 7-16. Average Time Spent Per Day Performing Activities Within Specified Intensity Categories, and Average

Ventilation Rates Associated With These Activity Categories, for Females According to Age Category (continued)

Age Category

# NHANES

Participants

Reporting

Activity

Average

Duration

(hr/day)

Spent at

Activity

Ventilation Rate During This

Activity1

Daily Ventilation Rate Associated

With This Activity2

Unadjusted for

Body Weight

(L/min)

Adjusted for

Body Weight

(L/min-kg)

Unadjusted for

Body Weight

(L/day)

Adjusted for

Body Weight

(L/day-kg)

7-30

Light Intensity Activities (1.5 < METS # 3.0)

Birth to <1 year 415 6.0 7.32 0.978 2,727 362.7

1 year 245 5.6 11.62 1.050 4,019 366.8

2 years 255 5.8 11.99 0.897 4,255 318.5

3 to <6 years 543 6.3 10.92 0.619 4,148 235.6

6 to <11 years 894 7.3 11.07 0.382 4,845 167.0

11 to <16 years 1,451 7.6 12.02 0.225 5,454 101.9

16 to <21 years 1,182 7.0 11.08 0.174 4,660 73.2

21 to <31 years 1,023 6.4 10.55 0.149 4,075 57.7

31 to <41 years 869 6.5 11.07 0.154 4,338 60.5

41 to <51 years 763 6.6 11.78 0.161 4,656 63.8

51 to <61 years 622 6.5 12.02 0.161 4,714 63.2

61 to <71 years 700 6.2 10.82 0.147 4,046 55.1

71 to <81 years 470 6.0 10.83 0.158 3,873 56.6

81 years and older 306 5.3 10.40 0.167 3,308 52.9

Moderate Intensity Activities (3.0 < METS # 6.0)

Birth to <1 year 415 3.9 13.98 1.866 3,222 434.0

1 year 245 4.0 20.98 1.896 5,118 452.5

2 years 255 3.3 21.34 1.600 4,076 306.0

3 to <6 years 543 3.4 20.01 1.135 3,986 226.0

6 to <11 years 894 2.6 21.00 0.723 3,220 111.0

11 to <16 years 1,451 2.0 23.55 0.441 2,852 53.3

16 to <21 years 1,182 3.3 23.22 0.365 4,586 72.0

21 to <31 years 1,023 4.8 22.93 0.325 6,769 95.9

31 to <41 years 869 5.0 22.70 0.316 6,927 96.4

41 to <51 years 763 5.0 24.49 0.333 7,559 102.1

51 to <61 years 622 4.6 25.24 0.339 7,026 94.6

61 to <71 years 700 3.3 21.42 0.292 4,255 58.0

71 to <81 years 470 2.5 21.09 0.308 3,140 45.8

81 years and older 306 2.1 20.87 0.335 2,580 41.4
Table 7-16. Average Time Spent Per Day Performing Activities Within Specified Intensity Categories, and Average

Ventilation Rates Associated With These Activity Categories, for Females According to Age Category (continued)

Age Category

# NHANES

Participants

Reporting

Activity

Average

Duration

(hr/day)

Spent at

Activity

Ventilation Rate During This

Activity1

Daily Ventilation Rate Associated

With This Activity2

Unadjusted for

Body Weight

(L/min)

Adjusted for

Body Weight

(L/min-kg)

Unadjusted for

Body Weight

(L/day)

Adjusted for

Body Weight

(L/day-kg)

7-31

High Intensity (METS > 6.0)

Birth to <1 year 79 0.2 24.19 3.263 244 32.3

1 year 55 0.2 36.48 3.376 471 44.3

2 years 130 0.2 37.58 2.800 355 25.6

3 to <6 years 347 0.2 34.53 1.979 407 23.4

6 to <11 years 707 0.2 39.39 1.331 568 18.7

11 to <16 years 1,170 0.3 46.56 0.879 840 15.8

16 to <21 years 887 0.2 44.09 0.696 621 9.8

21 to <31 years 796 0.3 45.68 0.650 725 10.2

31 to <41 years 687 0.2 44.44 0.613 646 8.9

41 to <51 years 515 0.3 46.98 0.653 725 10.1

51 to <61 years 424 0.3 47.35 0.634 965 13.0

61 to <71 years 465 0.3 40.02 0.544 777 10.5

71 to <81 years 304 0.3 40.64 0.594 718 10.5

81 years and older 188 0.3 41.88 0.666 654 10.7

1

 An individual’s ventilation rate for the given activity category equals the weighted average of the individual’s activity-specific

ventilation rates for activities falling within the category, estimated using a multiple linear regression model, with weights

corresponding to the number of minutes spent performing the activity. Numbers in these two columns represent averages,

calculated across individuals in the specified age category, of these weighted averages. These are weighted averages, with the

weights corresponding to the 4-year sampling weights assigned within NHANES 1999-2002.

2

 An individual’s daily average ventilation rate equals the product of the individual’s weighted average ventilation rate for the

given activity category (L/min), estimated using a multiple linear regression model, and the number of minutes per day that the

individual performs an activity within the category. Numbers in these two columns represent weighted averages across

individuals in the specified age category, with the weights corresponding to the 4-year sampling weights assigned within

NHANES 1999-2002.

Source: Lordo et al., 2006
7-32

Table 7-17. Descriptive Statistics for Daily Average Ventilation Rate (m3/day) in Males, by Age Category

Age Category N

Daily Average Ventilation Rate, Unadjusted for Body Weight

 ( ; m3 V& /day) E

Daily Average Ventilation Rate, Adju

 ( /BW: m3 V& /day-

E

Mean

Percentiles Maximum Mean Percentiles 

5th 10th 25th 50th 75th 90th 95th 5th 10th 25th 50th 75

Birth to <1 year 419 8.76 4.77 5.70 7.16 8.70 10.43 11.93 12.69 17.05 1.093 0.913 0.943 1.002 1.085 1.1

1 year 308 13.49 9.73 10.41 11.65 13.11 15.02 17.03 17.89 24.24 1.186 0.964 1.017 1.088 1.171 1.2

2 years 261 13.23 9.45 10.20 11.43 13.19 14.49 16.27 17.71 28.17 0.948 0.781 0.816 0.873 0.943 1.0

3 to <6 years 540 12.65 10.42 10.87 11.40 12.58 13.64 14.63 15.41 19.52 0.703 0.523 0.555 0.613 0.693 0.7

6 to <11 years 940 13.42 10.08 10.69 11.73 13.09 14.73 16.56 17.72 24.97 0.441 0.318 0.343 0.376 0.434 0.4

11 to <16 years 1337 15.32 11.41 12.11 13.27 14.79 16.81 19.54 21.21 28.54 0.285 0.208 0.221 0.246 0.276 0.316 to <21 years 1241 17.22 12.60 13.41 14.48 16.63 19.16 21.94 23.38 39.21 0.229 0.168 0.181 0.202 0.228 0.2

Individual daily averages are weighted by their 4-year sampling weights as assigned within NHANES 1999-2002 when calculating the statistics in this 

estimated using a multiple linear regression model.

Source: Lordo et al., 2006
7-33

Table 7-18. Descriptive Statistics for Daily Average Ventilation Rate (m3/day) in Females, by Age Category

Age Category N

Daily Average Ventilation Rate, Unadjusted for Body Weight

 ( ; m3 V& /day) E

Daily Average Ventilation Rate, Adju

 ( /BW: m3 V& /day-

E

Mean

Percentiles Maximum Mean Percentiles 

5th 10th 25th 50th 75th 90th 95th 5th 10th 25th 50th 75

Birth to <1 year 415 8.53 4.84 5.48 6.83 8.41 9.78 11.65 12.66 26.26 1.142 0.913 0.969 1.037 1.127 1.2

1 year 245 13.31 9.08 10.12 11.24 13.03 14.64 17.45 18.62 24.77 1.197 0.975 1.013 1.102 1.178 1.2

2 years 255 12.74 8.91 10.07 11.38 12.60 13.96 15.58 16.37 23.01 0.955 0.820 0.840 0.890 0.956 1.0

3 to <6 years 543 12.16 9.87 10.38 11.20 12.02 13.01 14.03 14.93 19.74 0.691 0.482 0.536 0.596 0.684 0.7

6 to <11 years 894 12.41 9.99 10.35 11.01 11.95 13.42 15.13 16.34 20.82 0.427 0.279 0.307 0.357 0.427 0.4

11 to <16 years 1451 13.44 10.47 11.11 12.04 13.08 14.54 16.25 17.41 26.58 0.251 0.189 0.198 0.220 0.245 0.216 to <21 years 1182 13.59 9.86 10.61 11.78 13.20 15.02 17.12 18.29 30.11 0.214 0.158 0.169 0.190 0.208 0.2

Individual daily averages are weighted by their 4-year sampling weights as assigned within NHANES 1999-2002 when calculating the statistics in this 

estimated using a multiple linear regression model.

Source: Lordo et al., 2006
7-34

Table 7-19. Descriptive Statistics for Duration of Time (hr/day) Spent Performing Activities Within the Specified Activity Category, by 

Categories

Age Category

Duration (hr/day) Spent at Activity – Males Duration (hr/day) Spent at Activity 

N Mean

Percentiles Maximum N Mean Percentiles 

5th 10th 25th 50th 75th 90th 95th 5th 10th 25th 50th 75

Sleep or nap (Activity ID = 14500)

Birth to <1 year 419 13.51 12.63 12.78 13.19 13.53 13.88 14.24 14.46 15.03 415 12.99 12.00 12.16 12.53 12.96 13.

1 year 308 12.61 11.89 12.15 12.34 12.61 12.89 13.13 13.29 13.79 245 12.58 11.59 11.88 12.29 12.63 12.

2 years 261 12.06 11.19 11.45 11.80 12.07 12.39 12.65 12.75 13.40 255 12.09 11.45 11.68 11.86 12.08 12.

3 to <6 years 540 11.18 10.57 10.70 10.94 11.18 11.45 11.63 11.82 12.39 543 11.13 10.45 10.70 10.92 11.12 11.

6 to <11 years 940 10.18 9.65 9.75 9.93 10.19 10.39 10.59 10.72 11.24 894 10.26 9.55 9.73 10.01 10.27 10.

11 to <16 years 1337 9.38 8.84 8.94 9.15 9.38 9.61 9.83 9.95 10.33 1451 9.57 8.82 8.97 9.27 9.55 9.8

16 to <21 years 1241 8.69 7.91 8.08 8.36 8.67 9.03 9.34 9.50 10.44 1182 9.08 8.26 8.44 8.74 9.08 9.3

Sedentary & Passive Activities (METS # 1.5 -- Includes Sleep or Nap)

Birth to <1 year 419 14.95 13.82 14.03 14.49 14.88 15.44 15.90 16.12 17.48 415 14.07 12.86 13.05 13.53 14.08 14.

1 year 308 14.27 13.22 13.33 13.76 14.25 14.74 15.08 15.38 16.45 245 14.32 13.02 13.25 13.73 14.31 14.

2 years 261 14.62 13.52 13.67 14.11 14.54 15.11 15.60 15.77 17.28 255 14.86 13.81 13.95 14.44 14.81 15.

3 to <6 years 540 14.12 13.01 13.18 13.54 14.03 14.53 15.26 15.62 17.29 543 14.27 12.88 13.15 13.56 14.23 14.

6 to <11 years 940 13.51 12.19 12.45 12.86 13.30 13.85 14.82 15.94 19.21 894 13.97 12.49 12.74 13.22 13.82 14.

11 to <16 years 1337 13.85 12.39 12.65 13.06 13.61 14.30 15.41 16.76 18.79 1451 14.19 12.38 12.76 13.34 14.05 14.

16 to <21 years 1241 13.21 11.39 11.72 12.32 13.08 13.97 14.83 15.44 18.70 1182 13.58 11.80 12.17 12.79 13.52 14.

Light Intensity Activities (1.5 < METS # 3.0)

Birth to <1 year 419 5.30 2.97 3.25 3.71 4.52 7.29 8.08 8.50 9.91 415 6.00 3.49 3.70 4.26 5.01 8.4

1 year 308 5.52 2.68 2.89 3.37 4.31 8.23 9.04 9.73 10.90 245 5.61 2.83 2.94 3.46 4.39 8.2

2 years 261 5.48 3.06 3.26 3.85 4.58 7.58 8.83 9.04 9.92 255 5.78 3.20 3.54 4.29 5.33 7.4

3 to <6 years 540 6.60 3.86 4.25 5.16 6.20 8.26 9.31 9.70 10.74 543 6.25 3.78 4.10 4.79 5.84 7.8

6 to <11 years 940 7.62 5.07 5.57 6.63 7.63 8.72 9.78 10.12 11.59 894 7.27 4.63 5.46 6.33 7.17 8.3

11 to <16 years 1337 7.50 4.48 5.59 6.75 7.67 8.51 9.19 9.63 10.91 1451 7.55 4.89 5.62 6.75 7.67 8.5

16 to <21 years 1241 7.13 4.37 4.97 6.00 7.02 8.29 9.43 10.03 11.50 1182 6.98 4.60 5.08 5.91 6.85 7.9
Age Category

Duration (hr/day) Spent at Activity – Males Duration (hr/day) Spent at Activity 

N Mean

Percentiles Maximum N Mean Percentiles 

5th 10th 25th 50th 75th 90th 95th 5th 10th 25th 50th 75

7-35

Moderate Intensity Activities (3.0 < METS # 6.0)

Birth to <1 year 419 3.67 0.63 0.97 1.74 4.20 5.20 5.80 6.21 7.52 415 3.91 0.53 0.74 1.10 4.87 5.7

1 year 308 4.04 0.45 0.59 1.14 5.29 6.06 6.61 6.94 7.68 245 4.02 0.52 0.73 1.08 5.14 6.1

2 years 261 3.83 0.59 0.76 1.23 4.74 5.37 5.82 6.15 7.40 255 3.27 0.50 0.78 1.22 4.01 4.8

3 to <6 years 540 3.15 0.55 0.75 1.30 3.80 4.52 5.11 5.32 6.30 543 3.35 0.70 0.89 1.61 3.88 4.7

6 to <11 years 940 2.66 0.65 0.92 1.65 2.68 3.57 4.36 4.79 5.95 894 2.57 0.65 0.95 1.82 2.66 3.4

11 to <16 years 1337 2.35 0.88 1.09 1.66 2.30 3.02 3.62 3.89 5.90 1451 2.01 0.89 1.08 1.45 1.96 2.5

16 to <21 years 1241 3.35 1.13 1.42 2.19 3.45 4.37 5.24 5.59 6.83 1182 3.26 1.27 1.48 2.21 3.39 4.2

High Intensity (METS > 6.0)

Birth to <1 year 183 0.20 0.00 0.00 0.01 0.14 0.28 0.50 0.59 0.96 79 0.17 0.03 0.05 0.09 0.14 0.2

1 year 164 0.31 0.01 0.01 0.03 0.22 0.56 0.78 0.93 1.52 55 0.22 0.03 0.05 0.09 0.18 0.3

2 years 162 0.10 0.00 0.01 0.03 0.05 0.14 0.25 0.33 0.48 130 0.15 0.00 0.01 0.03 0.08 0.1

3 to <6 years 263 0.27 0.02 0.03 0.04 0.13 0.33 0.75 1.16 1.48 347 0.19 0.01 0.02 0.05 0.10 0.2

6 to <11 years 637 0.32 0.01 0.01 0.03 0.13 0.38 1.10 1.50 3.20 707 0.24 0.02 0.03 0.06 0.12 0.2

11 to <16 years 1111 0.38 0.03 0.04 0.10 0.21 0.47 1.03 1.34 2.35 1170 0.30 0.03 0.04 0.08 0.19 0.4

16 to <21 years 968 0.40 0.03 0.04 0.14 0.27 0.53 0.99 1.29 2.59 887 0.24 0.01 0.03 0.08 0.18 0.3

Individual measures are weighted by their 4-year sampling weights as assigned within NHANES 1999-2002 when calculating the statistics in this table

estimated using a multiple linear regression model.

Source: Lordo et al., 2006.
7-36

Table 7-20. Confidence in Inhalation Rate Recommendations

Considerations Rationale Rating

Study Elements

 Peer Review

The key study used in the recommendations has

undergone internal peer review, but not external

review yet. The primary data used in the study

have been peer reviewed.

Medium

 Accessibility The Lordo et al. 2006 is not yet available in the

peer review literature, however the primary data

sets used in the study are publicly available.

Medium

 Reproducibility Results can be reproduced using the primary data

publicly available.

Medium

 Focus on factor of interest Study focused on ventilation rates and factors

influencing them.

High

 Data pertinent to U.S. Studies conducted in the U.S. High

 Primary data Lordo et al. 2006 is an analysis of existing primary

data.

Medium

 Currency Recent studies were evaluated. High

 Adequacy of data collection period Effort was made to collect data over time. High

 Validity of approach Measurements were made by indirect methods. Medium

 Representativeness of the population The key study sampled a large and representative

of the U.S. general population.

High

 Characterization of variability Variability was presented in a cursory manner 

through calculation of summary statistics.

High

 Lack of bias in study design Subjects were selected randomly from the U.S.

population.

High

 Measurement error Inhalation rates were not measured directly. 

Rather, they were estimated using other

measurements (i.e., activity patterns, metabolic

equivalents and body weight). Measurement error

is well documented by statistics, but procedures

measure factor indirectly.

Medium

Other Elements

 Number of studies

One key study contributed the recommended

values; five additional relevant studies were

evaluated.

Low

 Agreement between researchers There is general agreement among researchers

using different experimental methods.

High

Overall Rating Recommendations are based on one study not yet

published, but it is the most recent data and

scientific methodology available. 

Medium
7-37

Table 7-21. Summary of Recommended Values For Inhalation

Activity Level Age Range

(years)

Males Females

Mean m3

/day N Mean m3/day N

Long-term Exposures

(All)

(Percentiles see Tables 7-

13 and 7-14)

 birth to <1 year

 1 to <2 years

 2 to <3 years

 3 to <6 years

 6 to <11 years

 11 to <16 years

 16 to <21 years

8.76

13.49

13.23

12.65

13.42

15.32

17.22

419

308

261

540

940

1337

1241

8.53

13.31

12.74

12.16

12.41

13.44

13.59

415

245

255

543

894

1451

1182

Short-term Exposures

Sleep or Nap

(Percentiles see Tables 7-

15 and 7-16)

 birth to <1 year

 1 to <2 years

 2 to <3 years

 3 to <6 years

 6 to <11 years

 11 to <16 years

 16 to <21 years

4.44

6.48

6.64

6.28

6.64

7.57

7.65

419

308

261

540

940

1337

1241

4.20

6.61

6.57

6.02

6.28

6.93

6.34

415

245

255

543

894

1451

1182

Sedentary/Passive

(Percentiles see Tables 7-

15 and 7-16)

 birth to <1 year

 1 to <2 years

 2 to <3 years

 3 to <6 years

 6 to <11 years

 11 to <16 years

 16 to <21 years

4.58

6.65

6.90

6.60

7.01

8.12

8.29

419

308

261

540

940

1337

1241

4.32

6.78

6.81

6.34

6.68

7.50

6.85

415

245

255

543

894

1451

1182

Light Intensity

(Percentiles see Tables 7-

15 and 7-16)

 birth to <1 year

 1 to <2 years

 2 to <3 years

 3 to <6 years

 6 to <11 years

 11 to <16 years

 16 to <21 years

11.43

16.65

16.80

16.36

16.76

19.04

19.31

419

308

261

540

940

1337

1241

10.54

16.73

17.27

15.72

15.94

17.31

15.96

415

245

255

543

894

1451

1182

Moderate Intensity

(Percentiles see Tables 7-

15 and 7-16)

 birth to <1 year

 1 to <2 years

 2 to <3 years

 3 to <6 years

 6 to <11 years

 11 to <16 years

 16 to <21 years

20.87

30.74

31.02

30.28

32.08

38.02

41.79

419

308

261

540

940

1337

1241

20.13

30.21

30.73

28.81

30.24

33.91

33.44

415

245

255

543

894

1451

1182

High Intensity

(Percentiles see Tables 7-

15 and 7-16)

 birth to <1 year

 1 to <2 years

 2 to <3 years

 3 to <6 years

 6 to <11 years

 11 to <16 years

 16 to <21 years

39.56

57.96

58.25

56.22

62.81

73.18

76.56

183

164

162

263

637

1111

968

34.83

52.53

54.12

49.72

56.72

67.05

63.49

79

55

130

347

707

1170

887
APPENDIX 7A

VENTILATION DATA
7A-1

Table 7A-1. Mean Minute Ventilation (Ve, L/min) by Group and Activity for Laboratory Protocols

Activity Young Childrena Childrena

Lying

Sitting

Standing

6.19

6.48

6.76

7.51

7.28

8.49

Walking 1.5 mph

1.875 mph

2.0 mph

2.25 mph

2.5 mph

3.0 mph

3.3 mph

4.0 mph

10.25

10.53

DNP

11.68

DNP

DNP

DNP

DNP

DNP

DNP

14.13

DNP

15.58

17.79

DNP

DNP

Running 3.5 mph

4.0 mph

4.5 mph

5.0 mph

6.0 mph

DNP

DNP

DNP

DNP

DNP

26.77

31.35

37.22

DNP

DNP

a

Young Children, male and female 3-5.9 years old; Children, male and female 6-12.9 years old;

DNP: group did not perform this protocol or N was too small for appropriate mean comparisons.

Source: Adams , 1993
7A-2

Table 7A-2. Mean Minute Ventilation (Ve, L/min) by Group and Activity for Field Protocols

Activitya Young Childrenb Childrenb

Play 11.31 17.89

a

Activities for which groups did not perform the protocol or N was too small for appropriate mean comparisons

were car driving, car riding, yardwork, housework, car maintenance, mowing, and woodworking.

b

Young Children, male and female 3-5.9 years old; Children, males and females 6-12.9 years old.

Source: Adams, 1993

Table 7A-3. Statistics of the Age/gender Cohorts Used to Develop Regression Equations for Predicting Basal

Metabolic Rates (BMR)

Gender,

Age (years)

BMR CV

Body

Weight

(kg)

N BMR Equationa r

MJ d-1 SD

Males

 Under 3

 3 to < 10

 10 to < 18

1.51

4.14

5.86

0.918

0.498

1.171

0.61

0.12

0.20

6.6

21

42

162

338

734

0.249 bw - 0.127

0.095 bw + 2.110

0.074 bw + 2.754

0.95

0.83

0.93

Females

 Under 3

 3 to < 10

 10 to < 18

1.54

3.85

5.04

0.915

0.493

0.780

0.59

0.13

0.15

6.9

21

38

137

413

575

0.244 bw - 0.130

0.085 bw + 2.033

0.056 bw + 2.898

0.96

0.81

0.8

a

Body weight (bw) in kg

SD: Standard deviation.

CV: Coefficient of variation (SD/mean)

r: coefficient of correlation

Source: Layton, 1993