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Impacts of travel activity and urbanicity on exposures to ambient oxides of nitrogen and on exposure disparities.

Gurram S, Stuart AL, Pinjari AR - Air Qual Atmos Health (2014)

Bottom Line: Time in nonresidential activities, including travel, was associated with an increase of 0.2 μg/m(3) per hour.Time spent travelling and at nonresidential locations contributed an average of 6 and 24 %, respectively, to the daily estimate.A mean error of 3.6 %, with range from -64 to 58 %, was found to result from using residence location alone.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, University of South Florida, Tampa, USA.

ABSTRACT

Daily exposures to ambient oxides of nitrogen were estimated here for residents of Hillsborough County, FL. The 2009 National Household Travel Survey provided geocoded data on fixed activity locations during each person-day sampled. Routes between activity locations were calculated from transportation network data, assuming the quickest travel path. To estimate daily exposure concentrations for each person-day, the exposure locations were matched with diurnally and spatially varying ambient pollutant concentrations derived from CALPUFF dispersion model results. The social distribution of exposures was analyzed by comparing frequency distributions of grouped daily exposure concentrations and by regression modeling. To investigate exposure error, the activity-based exposure estimates were also compared with estimates derived using residence location alone. The mean daily activity-based exposure concentration for the study sample was 17 μg/m(3), with values for individual person-day records ranging from 7.0 to 43 μg/m(3). The highest mean exposure concentrations were found for the following groups: black (20 μg/m(3)), below poverty (18 μg/m(3)), and urban residence location (22 μg/m(3)). Urban versus rural residence was associated with the largest increase in exposure concentration in the regression (8.3 μg/m(3)). Time in nonresidential activities, including travel, was associated with an increase of 0.2 μg/m(3) per hour. Time spent travelling and at nonresidential locations contributed an average of 6 and 24 %, respectively, to the daily estimate. A mean error of 3.6 %, with range from -64 to 58 %, was found to result from using residence location alone. Exposure error was highest for those who travel most, but lowest for the sociodemographic subgroups with higher mean exposure concentrations (including blacks and those from below poverty households). This work indicates the importance of urbanicity to social disparities in activity-based air pollution exposures. It also suggests that exposure error due to using residence location may be smaller for more exposed groups.

No MeSH data available.


Related in: MedlinePlus

Cumulative distributions of exposure error for population subgroups related to a personal attributes and b urban characteristics. Middle income refers to households with income above the poverty threshold but with incomes less than $75 thousand (k). Note that the racioethnic subgroup populations are not exclusive, and populations have overlapping individuals
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Fig7: Cumulative distributions of exposure error for population subgroups related to a personal attributes and b urban characteristics. Middle income refers to households with income above the poverty threshold but with incomes less than $75 thousand (k). Note that the racioethnic subgroup populations are not exclusive, and populations have overlapping individuals

Mentions: It is interesting to inquire whether estimated exposure error differs between demographic groups, i.e., whether residence-based estimates may be systematically biased for specific segments of the population; systematic biases could lead to systematic misclassification of exposures by group during health impact analyses. To address this question, Fig. 7 provides the cumulative distributions of exposure error for each of the sociodemographic groups studied above, with statistics provided in Table 2.Fig. 7


Impacts of travel activity and urbanicity on exposures to ambient oxides of nitrogen and on exposure disparities.

Gurram S, Stuart AL, Pinjari AR - Air Qual Atmos Health (2014)

Cumulative distributions of exposure error for population subgroups related to a personal attributes and b urban characteristics. Middle income refers to households with income above the poverty threshold but with incomes less than $75 thousand (k). Note that the racioethnic subgroup populations are not exclusive, and populations have overlapping individuals
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4338342&req=5

Fig7: Cumulative distributions of exposure error for population subgroups related to a personal attributes and b urban characteristics. Middle income refers to households with income above the poverty threshold but with incomes less than $75 thousand (k). Note that the racioethnic subgroup populations are not exclusive, and populations have overlapping individuals
Mentions: It is interesting to inquire whether estimated exposure error differs between demographic groups, i.e., whether residence-based estimates may be systematically biased for specific segments of the population; systematic biases could lead to systematic misclassification of exposures by group during health impact analyses. To address this question, Fig. 7 provides the cumulative distributions of exposure error for each of the sociodemographic groups studied above, with statistics provided in Table 2.Fig. 7

Bottom Line: Time in nonresidential activities, including travel, was associated with an increase of 0.2 μg/m(3) per hour.Time spent travelling and at nonresidential locations contributed an average of 6 and 24 %, respectively, to the daily estimate.A mean error of 3.6 %, with range from -64 to 58 %, was found to result from using residence location alone.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, University of South Florida, Tampa, USA.

ABSTRACT

Daily exposures to ambient oxides of nitrogen were estimated here for residents of Hillsborough County, FL. The 2009 National Household Travel Survey provided geocoded data on fixed activity locations during each person-day sampled. Routes between activity locations were calculated from transportation network data, assuming the quickest travel path. To estimate daily exposure concentrations for each person-day, the exposure locations were matched with diurnally and spatially varying ambient pollutant concentrations derived from CALPUFF dispersion model results. The social distribution of exposures was analyzed by comparing frequency distributions of grouped daily exposure concentrations and by regression modeling. To investigate exposure error, the activity-based exposure estimates were also compared with estimates derived using residence location alone. The mean daily activity-based exposure concentration for the study sample was 17 μg/m(3), with values for individual person-day records ranging from 7.0 to 43 μg/m(3). The highest mean exposure concentrations were found for the following groups: black (20 μg/m(3)), below poverty (18 μg/m(3)), and urban residence location (22 μg/m(3)). Urban versus rural residence was associated with the largest increase in exposure concentration in the regression (8.3 μg/m(3)). Time in nonresidential activities, including travel, was associated with an increase of 0.2 μg/m(3) per hour. Time spent travelling and at nonresidential locations contributed an average of 6 and 24 %, respectively, to the daily estimate. A mean error of 3.6 %, with range from -64 to 58 %, was found to result from using residence location alone. Exposure error was highest for those who travel most, but lowest for the sociodemographic subgroups with higher mean exposure concentrations (including blacks and those from below poverty households). This work indicates the importance of urbanicity to social disparities in activity-based air pollution exposures. It also suggests that exposure error due to using residence location may be smaller for more exposed groups.

No MeSH data available.


Related in: MedlinePlus