Limits...
Associations between ozone and morbidity using the Spatial Synoptic Classification system.

Hanna AF, Yeatts KB, Xiu A, Zhu Z, Smith RL, Davis NN, Talgo KD, Arora G, Robinson PJ, Meng Q, Pinto JP - Environ Health (2011)

Bottom Line: In all models we adjusted for dew point and day-of-the-week effects related to hospital admissions.Ozone was associated with MI only under the extreme moist tropical (5-day lag) air masses.Elevated ozone levels are associated with dry tropical, dry moderate, and moist tropical air masses, with the highest ozone levels being associated with the dry tropical air mass.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for the Environment, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. ahanna@unc.edu

ABSTRACT

Background: Synoptic circulation patterns (large-scale tropospheric motion systems) affect air pollution and, potentially, air-pollution-morbidity associations. We evaluated the effect of synoptic circulation patterns (air masses) on the association between ozone and hospital admissions for asthma and myocardial infarction (MI) among adults in North Carolina.

Methods: Daily surface meteorology data (including precipitation, wind speed, and dew point) for five selected cities in North Carolina were obtained from the U.S. EPA Air Quality System (AQS), which were in turn based on data from the National Climatic Data Center of the National Oceanic and Atmospheric Administration. We used the Spatial Synoptic Classification system to classify each day of the 9-year period from 1996 through 2004 into one of seven different air mass types: dry polar, dry moderate, dry tropical, moist polar, moist moderate, moist tropical, or transitional. Daily 24-hour maximum 1-hour ambient concentrations of ozone were obtained from the AQS. Asthma and MI hospital admissions data for the 9-year period were obtained from the North Carolina Department of Health and Human Services. Generalized linear models were used to assess the association of the hospitalizations with ozone concentrations and specific air mass types, using pollutant lags of 0 to 5 days. We examined the effect across cities on days with the same air mass type. In all models we adjusted for dew point and day-of-the-week effects related to hospital admissions.

Results: Ozone was associated with asthma under dry tropical (1- to 5-day lags), transitional (3- and 4-day lags), and extreme moist tropical (0-day lag) air masses. Ozone was associated with MI only under the extreme moist tropical (5-day lag) air masses.

Conclusions: Elevated ozone levels are associated with dry tropical, dry moderate, and moist tropical air masses, with the highest ozone levels being associated with the dry tropical air mass. Certain synoptic circulation patterns/air masses in conjunction with ambient ozone levels were associated with increased asthma and MI hospitalizations.

Show MeSH

Related in: MedlinePlus

Ozone distribution of the seven air masses. (a) The 5-year period 1996-2000 and (b) the 4-year period 2001-2004. Probability (expressed as a percentage) of finding ozone (O3) concentrations above a threshold concentration for a given air mass (P(O3/AM)).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3117763&req=5

Figure 6: Ozone distribution of the seven air masses. (a) The 5-year period 1996-2000 and (b) the 4-year period 2001-2004. Probability (expressed as a percentage) of finding ozone (O3) concentrations above a threshold concentration for a given air mass (P(O3/AM)).

Mentions: The above analyses utilize data from the entire 9-year period to produce the results shown. It is of interest to see whether such findings would also be true for subsets of the analysis period. Figure 6 shows the same statistics revealed in Figure 5 but broken down into one five-year and one four-year period (1996-2000 and 2001-2004). As can be seen, there were notable shifts in the relative importance of different air masses associated with high ozone. During the first (five-year) period (Figure 6a), ozone up to ~85 ppb was associated with either the DT or MT air masses, but above this level ozone was more likely to be found under DT or DM air masses. During the second (four-year) period (Figure 6b), the MT air mass decreases in importance compared to the DT and DM air masses above about 60 ppb. Although not shown, there were much larger changes from year to year.


Associations between ozone and morbidity using the Spatial Synoptic Classification system.

Hanna AF, Yeatts KB, Xiu A, Zhu Z, Smith RL, Davis NN, Talgo KD, Arora G, Robinson PJ, Meng Q, Pinto JP - Environ Health (2011)

Ozone distribution of the seven air masses. (a) The 5-year period 1996-2000 and (b) the 4-year period 2001-2004. Probability (expressed as a percentage) of finding ozone (O3) concentrations above a threshold concentration for a given air mass (P(O3/AM)).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117763&req=5

Figure 6: Ozone distribution of the seven air masses. (a) The 5-year period 1996-2000 and (b) the 4-year period 2001-2004. Probability (expressed as a percentage) of finding ozone (O3) concentrations above a threshold concentration for a given air mass (P(O3/AM)).
Mentions: The above analyses utilize data from the entire 9-year period to produce the results shown. It is of interest to see whether such findings would also be true for subsets of the analysis period. Figure 6 shows the same statistics revealed in Figure 5 but broken down into one five-year and one four-year period (1996-2000 and 2001-2004). As can be seen, there were notable shifts in the relative importance of different air masses associated with high ozone. During the first (five-year) period (Figure 6a), ozone up to ~85 ppb was associated with either the DT or MT air masses, but above this level ozone was more likely to be found under DT or DM air masses. During the second (four-year) period (Figure 6b), the MT air mass decreases in importance compared to the DT and DM air masses above about 60 ppb. Although not shown, there were much larger changes from year to year.

Bottom Line: In all models we adjusted for dew point and day-of-the-week effects related to hospital admissions.Ozone was associated with MI only under the extreme moist tropical (5-day lag) air masses.Elevated ozone levels are associated with dry tropical, dry moderate, and moist tropical air masses, with the highest ozone levels being associated with the dry tropical air mass.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for the Environment, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. ahanna@unc.edu

ABSTRACT

Background: Synoptic circulation patterns (large-scale tropospheric motion systems) affect air pollution and, potentially, air-pollution-morbidity associations. We evaluated the effect of synoptic circulation patterns (air masses) on the association between ozone and hospital admissions for asthma and myocardial infarction (MI) among adults in North Carolina.

Methods: Daily surface meteorology data (including precipitation, wind speed, and dew point) for five selected cities in North Carolina were obtained from the U.S. EPA Air Quality System (AQS), which were in turn based on data from the National Climatic Data Center of the National Oceanic and Atmospheric Administration. We used the Spatial Synoptic Classification system to classify each day of the 9-year period from 1996 through 2004 into one of seven different air mass types: dry polar, dry moderate, dry tropical, moist polar, moist moderate, moist tropical, or transitional. Daily 24-hour maximum 1-hour ambient concentrations of ozone were obtained from the AQS. Asthma and MI hospital admissions data for the 9-year period were obtained from the North Carolina Department of Health and Human Services. Generalized linear models were used to assess the association of the hospitalizations with ozone concentrations and specific air mass types, using pollutant lags of 0 to 5 days. We examined the effect across cities on days with the same air mass type. In all models we adjusted for dew point and day-of-the-week effects related to hospital admissions.

Results: Ozone was associated with asthma under dry tropical (1- to 5-day lags), transitional (3- and 4-day lags), and extreme moist tropical (0-day lag) air masses. Ozone was associated with MI only under the extreme moist tropical (5-day lag) air masses.

Conclusions: Elevated ozone levels are associated with dry tropical, dry moderate, and moist tropical air masses, with the highest ozone levels being associated with the dry tropical air mass. Certain synoptic circulation patterns/air masses in conjunction with ambient ozone levels were associated with increased asthma and MI hospitalizations.

Show MeSH
Related in: MedlinePlus