Limits...
Emissions from an international airport increase particle number concentrations 4-fold at 10 km downwind.

Hudda N, Gould T, Hartin K, Larson TV, Fruin SA - Environ. Sci. Technol. (2014)

Bottom Line: The total freeway length in Los Angeles is 1500 km.These results suggest that airport emissions are a major source of PN in Los Angeles that are of the same general magnitude as the entire urban freeway network.They also indicate that the air quality impact areas of major airports may have been seriously underestimated.

View Article: PubMed Central - PubMed

Affiliation: Keck School of Medicine, Department of Preventive Medicine, University of Southern California , Los Angeles, California 90089, United States.

ABSTRACT
We measured the spatial pattern of particle number (PN) concentrations downwind from the Los Angeles International Airport (LAX) with an instrumented vehicle that enabled us to cover larger areas than allowed by traditional stationary measurements. LAX emissions adversely impacted air quality much farther than reported in previous airport studies. We measured at least a 2-fold increase in PN concentrations over unimpacted baseline PN concentrations during most hours of the day in an area of about 60 km(2) that extended to 16 km (10 miles) downwind and a 4- to 5-fold increase to 8-10 km (5-6 miles) downwind. Locations of maximum PN concentrations were aligned to eastern, downwind jet trajectories during prevailing westerly winds and to 8 km downwind concentrations exceeded 75 000 particles/cm(3), more than the average freeway PN concentration in Los Angeles. During infrequent northerly winds, the impact area remained large but shifted to south of the airport. The freeway length that would cause an impact equivalent to that measured in this study (i.e., PN concentration increases weighted by the area impacted) was estimated to be 280-790 km. The total freeway length in Los Angeles is 1500 km. These results suggest that airport emissions are a major source of PN in Los Angeles that are of the same general magnitude as the entire urban freeway network. They also indicate that the air quality impact areas of major airports may have been seriously underestimated.

Show MeSH

Related in: MedlinePlus

Comparison of the spatial scale of freeway impacts comparedtoairport impacts for monitoring during nighttime on August 23–24,2013.
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4215878&req=5

fig6: Comparison of the spatial scale of freeway impacts comparedtoairport impacts for monitoring during nighttime on August 23–24,2013.

Mentions: PN concentrationincreases from ground level line sources such as freeways, under conditionsof daytime crosswind dilution, decrease exponentially with increasingdownwind distance and return to baseline concentrations within 200–300m.17 The two N–S freeways (I-405and I-110 that run perpendicular to the prevailing winds) did notcontribute appreciably to elevated PN concentrations in areas wherewe observed large impacts from LAX on PN concentrations. This is illustratedin Figure 6, which contains two enlargementsto show the increase in PN number concentrations over approximately250 m distance downwind of I-405, a distance and an increase in PNconcentration that is not discernible at the scale of Figures 2 and 3. The panel in Figure 6(c) at 1:10 000 scale shows the PN concentrationincrease of about 24 000/cm3. The maximum PN concentrationwas not immediately downwind of the freeway because at this locationthere is an elevated overpass and some distance is needed for emissionsto reach the ground.


Emissions from an international airport increase particle number concentrations 4-fold at 10 km downwind.

Hudda N, Gould T, Hartin K, Larson TV, Fruin SA - Environ. Sci. Technol. (2014)

Comparison of the spatial scale of freeway impacts comparedtoairport impacts for monitoring during nighttime on August 23–24,2013.
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215878&req=5

fig6: Comparison of the spatial scale of freeway impacts comparedtoairport impacts for monitoring during nighttime on August 23–24,2013.
Mentions: PN concentrationincreases from ground level line sources such as freeways, under conditionsof daytime crosswind dilution, decrease exponentially with increasingdownwind distance and return to baseline concentrations within 200–300m.17 The two N–S freeways (I-405and I-110 that run perpendicular to the prevailing winds) did notcontribute appreciably to elevated PN concentrations in areas wherewe observed large impacts from LAX on PN concentrations. This is illustratedin Figure 6, which contains two enlargementsto show the increase in PN number concentrations over approximately250 m distance downwind of I-405, a distance and an increase in PNconcentration that is not discernible at the scale of Figures 2 and 3. The panel in Figure 6(c) at 1:10 000 scale shows the PN concentrationincrease of about 24 000/cm3. The maximum PN concentrationwas not immediately downwind of the freeway because at this locationthere is an elevated overpass and some distance is needed for emissionsto reach the ground.

Bottom Line: The total freeway length in Los Angeles is 1500 km.These results suggest that airport emissions are a major source of PN in Los Angeles that are of the same general magnitude as the entire urban freeway network.They also indicate that the air quality impact areas of major airports may have been seriously underestimated.

View Article: PubMed Central - PubMed

Affiliation: Keck School of Medicine, Department of Preventive Medicine, University of Southern California , Los Angeles, California 90089, United States.

ABSTRACT
We measured the spatial pattern of particle number (PN) concentrations downwind from the Los Angeles International Airport (LAX) with an instrumented vehicle that enabled us to cover larger areas than allowed by traditional stationary measurements. LAX emissions adversely impacted air quality much farther than reported in previous airport studies. We measured at least a 2-fold increase in PN concentrations over unimpacted baseline PN concentrations during most hours of the day in an area of about 60 km(2) that extended to 16 km (10 miles) downwind and a 4- to 5-fold increase to 8-10 km (5-6 miles) downwind. Locations of maximum PN concentrations were aligned to eastern, downwind jet trajectories during prevailing westerly winds and to 8 km downwind concentrations exceeded 75 000 particles/cm(3), more than the average freeway PN concentration in Los Angeles. During infrequent northerly winds, the impact area remained large but shifted to south of the airport. The freeway length that would cause an impact equivalent to that measured in this study (i.e., PN concentration increases weighted by the area impacted) was estimated to be 280-790 km. The total freeway length in Los Angeles is 1500 km. These results suggest that airport emissions are a major source of PN in Los Angeles that are of the same general magnitude as the entire urban freeway network. They also indicate that the air quality impact areas of major airports may have been seriously underestimated.

Show MeSH
Related in: MedlinePlus