This_DT0 event_NN1 primarily_AV0 took_VVD place_NN1 during_PRP January_NP0 2014._CRD After_PRP visual_AJ0 inspection_NN1 ,_PUN a_AT0 key_AJ0 indicator_NN1 was_VBD a_AT0 very_AV0 low_AJ0 negative_AJ0 value_NN1 reported_VVN by_PRP beta-attenuation_NN1 monitor_NN1 (_PUL BAM_NP0 )_PUR component_NN1 of_PRF the_AT0 instrument_NN1 ._SENT For_PRP periods_NN2 when_AVQ the_AT0 BAM_NN1 reported_VVD a_AT0 value_NN1 below_PRP −70_CRD μg_NP0 m−3_CRD ,_PUN two_CRD hours_NN2 prior_AJ0 to_PRP this_DT0 data_NN0 point_NN1 and_CJC 24_CRD hours_NN2 of_PRF data_NN0 afterward_AV0 were_VBD set_VVN to_PRP missing_VVG ._SENT As_CJS a_AT0 result_NN1 ,_PUN a_AT0 total_NN1 of_PRF 1.9_CRD %_NN0 of_PRF the_AT0 data_NN0 were_VBD flagged_VVN and_CJC removed_VVN from_PRP analysis_NN1 ._SENT After_PRP this_DT0 initial_AJ0 processing_NN1 ,_PUN data_NN0 were_VBD imported_VVN and_CJC analyzed_VVN using_VVG R_ZZ0 version_NN1 3.5.1_CRD ,_PUN with_PRP packages_NN2 including_PRP gdata_NN1 ,_PUN openair_NN1 ,_PUN replaced-dns_NN2 ,_PUN and_CJC plyr_NP0 ._SENT 
NTA_NP0 analysis_NN1 was_VBD conducted_VVN via_PRP MATLAB_NP0 ,_PUN using_VVG the_AT0 one-minute_AJ0 monitoring_NN1 data_NN0 at_PRP the_AT0 R2PIER_AJ0 site_NN1 and_CJC meteorological_AJ0 data_NN0 at_PRP a_AT0 Newark_NP0 Airport_NN1 (_PUL KEWR_NP0 )_PUR as_PRP inputs_NN2 ._SENT NTA_NP0 calculated_VVD local_AJ0 back-trajectories_NN2 per_PRP minute_NN1 using_VVG inverse_AJ0 distance-squared_AJ0 weighting_NN1 interpolation_NN1 of_PRF the_AT0 wind_NN1 data_NN0 at_PRP the_AT0 R2PIER_AJ0 site_NN1 and_CJC KEWR_NP0 Automated_AJ0 Surface_NN1 Observation_NN1 System_NN1 (_PUL ASOS_NP0 )_PUR 1-minute_AJ0 wind_NN1 data_NN0 ._SENT The_AT0 ASOS_NP0 wind_NN1 data_NN0 are_VBB two-minute_AJ0 averages_NN2 reported_VVD every_AT0 minute_NN1 from_PRP a_AT0 cup_NN1 anemometer_AJC while_CJS the_AT0 R2PIER_NP0 data_NN0 were_VBD produced_VVN by_PRP an_AT0 ultrasonic_AJ0 3-D_AJ0 anemometer_NN1 ._SENT The_AT0 wind_NN1 speed_NN1 and_CJC direction_NN1 at_PRP a_AT0 point_NN1 was_VBD determined_VVN as_PRP the_AT0 inverse-distance-squared_AJ0 weighted_AJ0 average_NN1 of_PRF the_AT0 wind_NN1 velocity_NN1 components_NN2 from_PRP these_DT0 two_CRD sites_NN2 ._SENT The_AT0 equations_NN2 for_PRP the_AT0 trajectory_NN1 and_CJC other_AJ0 NTA_NN1 calculations_NN2 are_VBB detailed_AJ0 in_PRP Henry_NP0 (_PUL 2008_CRD )_PUR and_CJC most_AV0 recently_AV0 in_PRP Henry_NP0 et_NP0 al._NP0 (_PUL 2019_CRD )_PUR ._SENT 
3._CRD RESULTS_NN2 AND_CJC DISCUSSION_NN1 
3.1_CRD ._SENT Study_NN1 Sampling_NN1 Conditions_NN2 and_CJC Overall_AJ0 Averages_NN2 
Shipping_NN1 activity_NN1 data_NN0 fluctuated_VVN throughout_PRP the_AT0 study_NN1 ,_PUN with_PRP TEUs_NP0 and_CJC cargo_NN1 ship_NN1 number_NN1 not_XX0 consistently_AV0 aligned_VVN (_PUL Fig._NN1 2_CRD )_PUR ._SENT The_AT0 spring_NN1 to_PRP summer_NN1 of_PRF 2015_CRD indicates_VVZ an_AT0 overall_AJ0 increase_NN1 in_PRP TEUs_NP0 relative_NN1 to_PRP previous_AJ0 years_NN2 ,_PUN however_AV0 the_AT0 number_NN1 of_PRF vessels_NN2 did_VDD not_XX0 increase_VVI in_PRP proportion_NN1 to_PRP the_AT0 TEUs_NP0 ._SENT In_PRP general_AJ0 ,_PUN vessel_NN1 activity_NN1 near_PRP the_AT0 Port_NN1 was_VBD dominated_VVN by_PRP hoteling_AJ0 operations_NN2 ,_PUN while_CJS in-transit_AJ0 operations_NN2 comprised_VVD a_AT0 small_AJ0 percentage_NN1 of_PRF activity_NN1 ._SENT The_AT0 wind_NN1 conditions_NN2 throughout_PRP the_AT0 sampling_NN1 study_NN1 are_VBB an_AT0 important_AJ0 consideration_NN1 to_PRP the_AT0 connection_NN1 of_PRF the_AT0 high_AJ0 time_NN1 resolution_NN1 monitoring_VVG data_NN0 to_PRP nearby_AJ0 source_NN1 areas_NN2 ._SENT Prevailing_AJ0 winds_NN2 were_VBD typically_AV0 from_PRP the_AT0 west_NN1 ,_PUN ranging_VVG from_PRP the_AT0 SW_NN1 to_PRP NW_NN1 ,_PUN with_PRP wind_NN1 speed_NN1 between_PRP 2_CRD –_PUN 4_CRD m_CRD s−1_CRD ._SENT However_AV0 ,_PUN over_PRP each_DT0 calendar_NN1 year_NN1 sampled_VVD ,_PUN monitoring_VVG data_NN0 were_VBD collected_VVN over_PRP all_DT0 wind_NN1 angles_NN2 ,_PUN with_PRP the_AT0 high_AJ0 time_NN1 resolution_NN1 measurements_NN2 equating_VVG to_PRP thousands_CRD of_PRF observations_NN2 for_PRP any_DT0 given_AJ0 10-degree_AJ0 wind_NN1 angle_NN1 ._SENT An_AT0 example_NN1 showing_VVG data_NN0 collection_NN1 frequency_NN1 by_PRP wind_NN1 speed_NN1 and_CJC direction_NN1 for_PRP the_AT0 four_CRD complete_AJ0 summer_NN1 quarters_NN2 is_VBZ provided_VVN in_PRP Fig._NN1 S2_CRD ._SENT Summary_NN1 data_NN0 on_PRP pollutant_AJ0 concentrations_NN2 and_CJC meteorology_NN1 ,_PUN as_CJS well_AV0 as_CJS by_PRP season_NN1 ,_PUN are_VBB provided_VVN in_PRP Table_NN1 2._CRD Seasonality_NN1 is_VBZ evident_AJ0 for_PRP all_DT0 parameters_NN2 measured_VVN ,_PUN with_PRP maximum_AJ0 concentrations_NN2 occurring_VVG during_PRP fall_NN1 and_CJC winter_NN1 months_NN2 (_PUL October_NP0 through_PRP March_NP0 )_PUR and_CJC lower_AJC concentrations_NN2 in_PRP the_AT0 summer_NN1 ._SENT 
Comparing_VVG this_DT0 location_NN1 with_PRP other_AJ0 areas_NN2 in_PRP the_AT0 United_NP0 States_NP0 for_PRP the_AT0 years_NN2 2012_CRD –_PUN 2015_CRD ,_PUN via_PRP the_AT0 U.S._NP0 EPA_NP0 's_POS trends_NN2 reports_NN2 (_PUL replaced-url_NP0 )_PUR ,_PUN the_AT0 CO_NN1 data_NN0 measured_VVN in_PRP this_DT0 study_NN1 was_VBD below_AV0 the_AT0 10th_ORD percentile_NN1 of_PRF 44_CRD Trend_NN1 Sites_NN2 reported_VVD nationally_AV0 ,_PUN NO2_AJ0 values_NN2 were_VBD similar_AJ0 to_PRP the_AT0 10th_ORD percentile_NN1 value_NN1 ,_PUN SO2_AJ0 values_NN2 were_VBD well_AV0 below_PRP the_AT0 10th_ORD percentile_NN1 ,_PUN and_CJC PM2.5_CRD levels_NN2 were_VBD slightly_AV0 below_PRP the_AT0 90th_ORD percentile_NN1 ._SENT 
The_AT0 nearest_AJS regulatory_AJ0 monitoring_NN1 station_NN1 to_PRP the_AT0 R2PIER_NP0 site_NN1 was_VBD New_NP0 Jersey_NP0 Department_NN1 of_PRF Environmental_AJ0 Protection_NN1 's_POS Elizabeth_NP0 Lab_NN1 Chemical_NN1 Speciation_NN1 Network_NN1 (_PUL CSN_NP0 )_PUR site_NN1 ,_PUN located_VVN approximately_AV0 2_CRD km_NN0 to_PRP the_AT0 southwest_NN1 (_PUL Latitude_NN1 :_PUN 40.641440_CRD ;_PUN Longitude_NN1 :_PUN −74.208365_CRD )_PUR ._SENT Whereas_CJS the_AT0 R2PIER_AJ0 site_NN1 measured_VVN PM2.5_NN1 continuously_AV0 with_PRP the_AT0 SHARP_AJ0 monitor_NN1 that_CJT combined_AJ0 nephelometry_NN1 and_CJC beta-attenuation_NN1 ,_PUN the_AT0 Elizabeth_NP0 Lab_NN1 site_NN1 measured_VVN PM2.5_NN1 using_VVG an_AT0 integrated_AJ0 filter_NN1 collection_NN1 approach_NN1 with_PRP subsequent_AJ0 laboratory_NN1 analysis_NN1 ._SENT The_AT0 integrated_AJ0 PM2.5_NN1 filters_NN2 were_VBD collected_VVN on_PRP a_AT0 1-in-3_CRD day_NN1 sampling_NN1 schedule_NN1 ._SENT Comparison_NN1 of_PRF the_AT0 particulate_NN1 matter_NN1 measurements_NN2 were_VBD made_VVN between_PRP the_AT0 two_CRD sites_NN2 ,_PUN with_PRP the_AT0 R2PIER_NP0 data_NN0 reduced_VVD and_CJC averaged_VVD to_TO0 match_VVI the_AT0 Elizabeth_NP0 Lab_NN1 CSN_NP0 site_NN1 sampling_NN1 schedule_NN1 (_PUL Fig._NN1 3_CRD )_PUR ._SENT Despite_PRP the_AT0 differences_NN2 in_PRP the_AT0 detection_NN1 methods_NN2 and_CJC distance_NN1 ,_PUN the_AT0 two_CRD PM2.5_CRD daily_AJ0 average_AJ0 values_NN2 had_VHD moderate_AJ0 correlation_NN1 (_PUL R2_CRD =_NP0 0.72_CRD )_PUR ._SENT Although_CJS the_AT0 R2PIER_AJ0 daily_AJ0 PM2.5_NN1 concentrations_NN2 were_VBD within_PRP 6_CRD %_NN0 of_PRF that_DT0 measured_VVN at_PRP the_AT0 Elizabeth_NP0 Lab_NN1 site_NN1 ,_PUN the_AT0 difference_NN1 in_PRP the_AT0 daily_AJ0 concentration_NN1 between_PRP the_AT0 two_CRD sites_NN2 ranged_VVD fairly_AV0 widely_AV0 (_PUL relative_AJ0 standard_AJ0 deviation_NN1 of_PRF 37_CRD %_NN0 )_PUR ._SENT The_AT0 R2PIER_NP0 BC_NP0 concentration_NN1 was_VBD compared_VVN against_PRP elemental_AJ0 carbon_NN1 (_PUL EC_NP0 )_PUR measured_VVN at_PRP Elizabeth_NP0 Lab_NN1 on_PRP the_AT0 1-in-3_CRD day_NN1 schedule_NN1 ._SENT Both_AV0 BC_NP0 and_CJC EC_NP0 are_VBB operationally_AV0 defined_VVN methods_NN2 ,_PUN with_PRP BC_AV0 measured_VVN optically_AV0 and_CJC converted_VVN to_PRP a_AT0 mass_AJ0 concentration_NN1 ,_PUN while_CJS EC_NP0 is_VBZ measured_VVN through_PRP a_AT0 thermal-optical_AJ0 method_NN1 that_CJT separates_VVZ organic_AJ0 and_CJC elemental_AJ0 carbonaceous_AJ0 mass_NN1 fractions_NN2 ._SENT Both_DT0 methods_NN2 are_VBB commonly_AV0 used_VVN and_CJC a_AT0 past_AJ0 study_NN1 intercomparing_VVG the_AT0 two_CRD methods_NN2 in_PRP the_AT0 New_AJ0 York_NP0 City_NN1 area_NN1 observed_VVD moderate_AJ0 correlation_NN1 but_CJC with_PRP slopes_NN2 ranging_VVG from_PRP 0.86_CRD to_PRP 1.23_CRD (_PUL Venkatachari_NP0 et_NP0 al._NP0 ,_PUN 2006_CRD )_PUR ._SENT When_CJS comparing_VVG BC_AV0 at_PRP R2PIER_NP0 and_CJC EC_NP0 at_PRP Elizabeth_NP0 Lab_NN1 sites_NN2 ,_PUN the_AT0 two_CRD methods_NN2 had_VHD moderate_AJ0 correlation_NN1 (_PUL R2_CRD =_NP0 0.43_CRD )_PUR ,_PUN with_PRP BC_NP0 concentrations_NN2 lower_AJC than_CJS EC_NP0 ._SENT 
3.2_CRD ._SENT Temporal_AJ0 Analysis_NN1 
In_PRP order_NN1 to_TO0 visualize_VVI the_AT0 coupled_AJ0 effects_NN2 of_PRF wind_NN1 direction_NN1 ,_PUN day_NN1 of_PRF week_NN1 and_CJC time_NN1 of_PRF day_NN1 ,_PUN two_CRD pollutants_NN2 (_PUL BC_NP0 and_CJC SO2_NP0 )_PUR affected_VVN primarily_AV0 by_PRP direct_AJ0 emissions_NN2 were_VBD visualized_VVN in_PRP a_AT0 polar_AJ0 annulus_NN1 graphs_NN2 oriented_VVN by_PRP wind_NN1 direction_NN1 and_CJC time_NN1 (_PUL Fig._NN1 S3_CRD )_PUR ._SENT For_PRP SO2_CRD ,_PUN maximum_AJ0 concentrations_NN2 occur_VVB during_PRP winds_NN2 from_PRP the_AT0 NE_NN1 and_CJC SW_NN1 ,_PUN with_PRP highest_AJS values_NN2 during_PRP morning_NN1 periods_NN2 ._SENT Lowest_AJS concentrations_NN2 appear_VVB to_TO0 occur_VVI on_PRP Sundays_NN2 ,_PUN during_PRP afternoon_NN1 periods_NN2 and_CJC with_PRP wind_NN1 from_PRP the_AT0 NW_NN1 ._SENT BC_NP0 has_VHZ similar_AJ0 temporal_AJ0 trends_NN2 ,_PUN however_AV0 appears_VVZ to_TO0 have_VHI higher_AJC concentrations_NN2 associated_VVN with_PRP winds_NN2 from_PRP the_AT0 N_ZZ0 and_CJC some_DT0 periods_NN2 of_PRF higher_AJC concentration_NN1 under_PRP winds_NN2 from_PRP the_AT0 E_NP0 /_PUN SE_NP0 compared_VVD to_PRP SO2_CRD ._SENT Shipping_NN1 activity_NN1 data_NN0 indicate_VVB a_AT0 repeatable_AJ0 diurnal_AJ0 pattern_NN1 with_PRP higher_AJC number_NN1 of_PRF pings_NN2 in_PRP the_AT0 evening_NN1 hours_NN2 and_CJC lowest_AJS mid-day_NN1 ,_PUN and_CJC with_PRP weekends_NN2 having_VHG lower_AJC activity_NN1 than_CJS weekdays_NN2 (_PUL Fig._NN1 S4_CRD )_PUR ._SENT The_AT0 general_AJ0 range_NN1 of_PRF variation_NN1 ,_PUN however_AV0 ,_PUN is_VBZ modest_AJ0 with_PRP less_AV0 than_CJS 10_CRD %_NN0 variation_NN1 above_AV0 /_PUN below_PRP the_AT0 average_NN1 ._SENT 
Throughout_PRP the_AT0 study_NN1 period_NN1 ,_PUN the_AT0 monitoring_NN1 station_NN1 exhibited_VVD variation_NN1 in_PRP hourly_AJ0 concentrations_NN2 (_PUL Fig._NN1 4_CRD )_PUR ._SENT The_AT0 coefficient_NN1 of_PRF variation_NN1 (_PUL CV_NN1 )_PUR was_VBD calculated_VVN by_PRP computing_VVG the_AT0 standard_AJ0 deviation_NN1 of_PRF the_AT0 hourly_AJ0 averages_NN2 divided_VVN by_PRP the_AT0 mean_NN1 of_PRF the_AT0 averages_NN2 ._SENT The_AT0 CV_NN1 was_VBD highest_AJS for_PRP NO_NN1 (_PUL 2.65_CRD )_PUR ,_PUN followed_VVN by_PRP SO2_CRD (_PUL 1.45_CRD )_PUR ,_PUN BC_NP0 (_PUL 1.21_CRD )_PUR ,_PUN PM2.5_CRD (_PUL 0.79_CRD )_PUR ,_PUN NO2_NP0 (_PUL 0.65_CRD )_PUR ,_PUN and_CJC CO_NN1 (_PUL 0.60_CRD )_PUR ._SENT In_PRP a_AT0 near-source_AJ0 environment_NN1 ,_PUN the_AT0 high_AJ0 concentration_NN1 excursions_NN2 of_PRF directly_AV0 emitted_AJ0 pollutants_NN2 would_VM0 likely_AV0 be_VBI related_VVN to_PRP proximate_AJ0 emissions_NN2 ._SENT To_TO0 explore_VVI how_AVQ the_AT0 overall_AJ0 concentrations_NN2 varied_VVN over_PRP time_NN1 ,_PUN as_CJS well_AV0 as_CJS the_AT0 occurrence_NN1 of_PRF high_AJ0 concentration_NN1 episodes_NN2 ,_PUN monthly_AJ0 percentiles_NN2 (_PUL 50th_ORD ,_PUN 75th_ORD ,_PUN and_CJC 95th_ORD )_PUR were_VBD compared_VVN (_PUL Fig._NN1 5_CRD )_PUR ,_PUN normalized_VVN to_PRP their_DPS respective_AJ0 January-2013_NN1 concentration_NN1 for_PRP ease_NN1 of_PRF visualization_NN1 ._SENT BC_NP0 stands_VVZ out_AVP in_PRP having_VHG a_AT0 slightly_AV0 different_AJ0 seasonal_AJ0 signal_NN1 in_PRP 2013_CRD ,_PUN with_PRP higher_AJC concentrations_NN2 in_PRP summer_NN1 2013_CRD while_CJS other_AJ0 parameters_NN2 had_VHD a_AT0 local_AJ0 minima_NN2 ._SENT For_PRP other_AJ0 periods_NN2 ,_PUN the_AT0 general_AJ0 seasonal_AJ0 trends_NN2 are_VBB similar_AJ0 across_PRP the_AT0 pollutant_AJ0 types_NN2 ._SENT SO2_NP0 stands_VVZ out_AVP in_PRP both_DT0 its_DPS decreased_AJ0 frequency_NN1 of_PRF outliers_NN2 (_PUL Fig._NN1 4_CRD )_PUR and_CJC an_AT0 associated_AJ0 decrease_NN1 in_PRP the_AT0 95th_ORD percentile_NN1 ,_PUN by_PRP approximately_AV0 half_DT0 ,_PUN in_PRP spring_NN1 /_PUN summer_NN1 2015_CRD compared_VVN to_PRP the_AT0 same_DT0 time_NN1 periods_NN2 in_PRP 2013_CRD and_CJC 2014._CRD This_DT0 shift_NN1 is_VBZ likely_AV0 related_VVN to_PRP the_AT0 introduction_NN1 of_PRF lower_AJC sulfur_NN1 fuel_NN1 requirements_NN2 which_DTQ were_VBD enforceable_AJ0 in_PRP January_NP0 2015._CRD 
Pollution_NN1 wind_NN1 roses_NN2 and_CJC wind-directional_AJ0 averages_NN2 of_PRF SO2_NN1 (_PUL Fig._NN1 6_CRD )_PUR for_PRP successive_AJ0 summer_NN1 quarters_NN2 (_PUL July_NP0 through_PRP September_NP0 )_PUR of_PRF the_AT0 four_CRD monitored_AJ0 years_NN2 reveal_VVB higher_AJC concentrations_NN2 associated_VVN with_PRP winds_NN2 from_PRP the_AT0 southwest_NN1 and_CJC northeast_NN1 ._SENT Compared_VVN to_PRP earlier_AJC summers_NN2 ,_PUN the_AT0 mean_NN1 decreases_VVZ from_PRP these_DT0 two_CRD wind_NN1 sectors_NN2 in_PRP summer_NN1 2015_CRD and_CJC shows_VVZ little_AJ0 wind_NN1 directionality_NN1 ._SENT Comparing_VVG 2014_CRD and_CJC 2015_CRD and_CJC selecting_VVG for_PRP winds_NN2 between_PRP 15_CRD and_CJC 75_CRD degrees_NN2 (_PUL winds_NN2 from_PRP the_AT0 NE_NN1 )_PUR ,_PUN mean_VVB concentrations_NN2 from_PRP that_DT0 sector_NN1 were_VBD significantly_AV0 lower_AJC by_PRP a_AT0 factor_NN1 of_PRF 0.55_CRD with_PRP a_AT0 Kruskal-Wallis_NP0 test_NN1 p-value_NN1 <_NN1 0.01_CRD ._SENT For_PRP the_AT0 SW_NN1 wind_NN1 sector_NN1 ,_PUN winds_NN2 between_PRP 195_CRD –_PUN 255_CRD degrees_NN2 ,_PUN there_EX0 was_VBD a_AT0 significant_AJ0 decrease_NN1 (_PUL p-value_VVB <_NN0 0.01_CRD )_PUR in_PRP mean_AJ0 SO2_NN1 by_PRP a_AT0 factor_NN1 of_PRF 0.60_CRD ._SENT 
3.3_CRD ._SENT Nonparametric_AJ0 Trajectory_NN1 Analysis_NN1 
A_AT0 major_AJ0 problem_NN1 in_PRP assessing_VVG the_AT0 impact_NN1 of_PRF emissions_NN2 changes_NN2 in_PRP the_AT0 Port_NN1 is_VBZ the_AT0 presence_NN1 of_PRF large_AJ0 nearby_AJ0 sources_NN2 ._SENT Nonparametric_AJ0 Trajectory_NN1 Analysis_NN1 (_PUL NTA_NP0 )_PUR was_VBD used_VVN to_TO0 separate_VVI out_AVP the_AT0 source_NN1 areas_NN2 for_PRP the_AT0 purpose_NN1 of_PRF sharpening_VVG the_AT0 trends_NN2 in_PRP the_AT0 air_NN1 quality_NN1 data_NN0 affected_VVN by_PRP mandated_AJ0 control_NN1 strategies_NN2 ._SENT The_AT0 study_NN1 period_NN1 had_VHD a_AT0 total_NN1 of_PRF 1_CRD ,_PUN 623_CRD ,_PUN 765_CRD one-hour_AJ0 back-trajectories_NN2 computed_VVN for_PRP each_DT0 minute_NN1 and_CJC ending_VVG at_PRP the_AT0 R2PIER_AJ0 site_NN1 ._SENT Of_PRF these_DT0 ,_PUN 100_CRD ,_PUN 521_CRD trajectories_NN2 passed_VVD directly_AV0 over_PRP the_AT0 Port_NN1 to_PRP the_AT0 NE_NN1 of_PRF the_AT0 site_NN1 (_PUL Fig._NN1 7_CRD )_PUR while_CJS passing_VVG over_PRP no_AT0 other_AJ0 known_AJ0 nearby_AJ0 source_NN1 areas_NN2 ._SENT Periods_NN2 low_AJ0 wind_NN1 speeds_NN2 (_PUL calms_VVZ )_PUR posed_VVD little_DT0 difficulty_NN1 for_PRP the_AT0 trajectory_NN1 calculations_NN2 ._SENT Wind_NN1 speeds_NN2 at_PRP Newark_NP0 airport_NN1 (_PUL KEWR_NP0 )_PUR are_VBB reported_VVN in_PRP whole_AJ0 knots_NN2 and_CJC only_AV0 0.52_CRD %_NN0 of_PRF the_AT0 observations_NN2 were_VBD less_AV0 than_CJS 1_CRD knot_NN1 (_PUL 0.514_CRD m_ZZ0 s−1_CRD )_PUR ._SENT Wind_NN1 speeds_NN2 at_PRP the_AT0 R2PIER_NP0 site_NN1 were_VBD reported_VVN to_PRP an_AT0 accuracy_NN1 of_PRF 0.1_CRD m_CRD s−1_CRD and_CJC only_AV0 0.16_CRD %_NN0 of_PRF the_AT0 observations_NN2 were_VBD less_AV0 than_CJS this_DT0 ._SENT 
This_DT0 technique_NN1 allowed_VVD the_AT0 impact_NN1 of_PRF the_AT0 Port_NN1 and_CJC other_AJ0 source_NN1 areas_NN2 to_TO0 be_VBI isolated_VVN for_PRP trend_NN1 analysis_NN1 ._SENT This_DT0 high_AJ0 volume_NN1 of_PRF trajectories_NN2 revealed_VVD expected_VVN SO2_CRD concentrations_NN2 at_PRP the_AT0 monitoring_NN1 site_NN1 on_PRP a_AT0 quarterly_AJ0 basis_NN1 as_PRP air_NN1 masses_NN2 passed_VVN over_PRP surrounding_VVG geographic_AJ0 areas_NN2 (_PUL Fig._NN1 8_CRD )_PUR ._SENT The_AT0 map_NN1 visualizations_NN2 show_VVB higher_AJC concentrations_NN2 associated_VVN with_PRP areas_NN2 to_PRP the_AT0 southwest_NN1 and_CJC northeast_NN1 of_PRF the_AT0 site_NN1 ,_PUN with_PRP several_DT0 quarters_NN2 showing_VVG higher_AJC source_NN1 area_NN1 contributions_NN2 from_PRP the_AT0 bay_NN1 area_NN1 due_AJ0 east_NN1 of_PRF the_AT0 monitoring_NN1 site_NN1 ._SENT BC_NP0 and_CJC NOx_NP0 results_NN2 (_PUL Figs._NN2 S5_CRD –_PUN S6_CRD )_PUR also_AV0 indicate_VVB higher_AJC concentrations_NN2 associated_VVN with_PRP areas_NN2 to_PRP the_AT0 northeast_NN1 of_PRF the_AT0 site_NN1 ,_PUN but_CJC relatively_AV0 less_AV0 from_PRP the_AT0 southwest_NN1 compared_VVN to_PRP the_AT0 SO2_AJ0 results_NN2 ._SENT Specifically_AV0 ,_PUN the_AT0 NTA_NP0 maps_NN2 show_VVB that_CJT the_AT0 highest_AJS average_AJ0 concentrations_NN2 at_PRP the_AT0 R2PIER_NP0 site_NN1 were_VBD associated_VVN primarily_AV0 with_PRP transport_NN1 from_PRP the_AT0 Port_NN1 to_PRP the_AT0 northeast_NN1 and_CJC the_AT0 container_NN1 terminal_NN1 to_PRP the_AT0 southwest_NN1 ,_PUN and_CJC occasionally_AV0 with_PRP transport_NN1 from_PRP Newark_NP0 Bay_NN1 ._SENT The_AT0 third_ORD quarter_NN1 (_PUL July_NP0 through_PRP September_NP0 )_PUR maps_NN2 show_VVB little_DT0 year-to-year_AJ0 variation_NN1 in_PRP geographic_AJ0 pattern_NN1 ,_PUN but_CJC a_AT0 great_AJ0 reduction_NN1 in_PRP maximum_AJ0 mixing_NN1 ratio_NN1 from_PRP 6_CRD to_PRP 1_CRD ppb_NN0 ._SENT 
Focusing_VVG on_PRP the_AT0 subset_NN1 of_PRF trajectories_NN2 that_CJT pass_VVB solely_AV0 over_PRP nearby_AJ0 geographic_AJ0 areas_NN2 associated_VVN with_PRP ship_NN1 traffic_NN1 and_CJC cargo_NN1 handling_NN1 ,_PUN Table_NN1 3_CRD provides_VVZ the_AT0 change_NN1 in_PRP concentration_NN1 at_PRP the_AT0 monitoring_NN1 site_NN1 for_PRP on-source_AJ0 trajectories_NN2 comparing_VVG the_AT0 last_ORD 5_CRD quarters_NN2 of_PRF the_AT0 study_NN1 (_PUL July_NP0 1_CRD ,_PUN 2014_CRD –_PUN October_NP0 1_CRD ,_PUN 2015_CRD )_PUR to_PRP the_AT0 first_ORD 5_CRD quarters_NN2 of_PRF the_AT0 study_NN1 (_PUL July_NP0 1_CRD ,_PUN 2012_CRD –_PUN October_NP0 1_CRD ,_PUN 2013_CRD )_PUR ._SENT These_DT0 longer_AJC time_NN1 spans_NN2 were_VBD selected_VVN to_TO0 provide_VVI a_AT0 significant_AJ0 volume_NN1 of_PRF trajectories_NN2 to_TO0 assess_VVI temporal_AJ0 shifts_NN2 in_PRP source_NN1 emission_NN1 areas_NN2 over_PRP the_AT0 study_NN1 period_NN1 and_CJC use_VVB identical_AJ0 spans_NN2 of_PRF months_NN2 to_TO0 minimize_VVI bias_NN1 due_AJ0 to_PRP seasonality_NN1 ._SENT This_DT0 analysis_NN1 indicates_VVZ a_AT0 decrease_NN1 of_PRF 34_CRD –_PUN 41_CRD %_NN0 ,_PUN 11_CRD –_PUN 17_CRD %_NN0 ,_PUN and_CJC 28_CRD –_PUN 41_CRD %_NN0 for_PRP SO2_CRD ,_PUN NOx_NP0 ,_PUN and_CJC BC_AV0 ,_PUN respectively_AV0 ,_PUN for_PRP air_NN1 masses_NN2 passing_VVG over_PRP three_CRD specific_AJ0 nearby_AJ0 source_NN1 regions_NN2 ._SENT An_AT0 important_AJ0 caveat_NN1 to_PRP these_DT0 findings_NN2 is_VBZ that_CJT the_AT0 concentrations_NN2 input_VVN to_PRP the_AT0 NTA_NP0 analysis_NN1 were_VBD absolute_AJ0 values_NN2 and_CJC not_XX0 background-subtracted_AJ0 ._SENT While_CJS the_AT0 influence_NN1 of_PRF background_NN1 seasonality_NN1 should_VM0 be_VBI lessened_VVN by_PRP using_VVG the_AT0 same_DT0 15_CRD months_NN2 for_PRP the_AT0 "_PUQ before_AV0 "_PUQ and_CJC "_PUQ after_PRP "_PUQ time_NN1 windows_NN2 and_CJC focusing_VVG on_PRP pollutants_NN2 expected_VVN to_TO0 be_VBI highly_AV0 influenced_VVN by_PRP nearby_AJ0 emissions_NN2 ,_PUN additional_AJ0 research_NN1 to_TO0 separate_VVI the_AT0 background_NN1 component_NN1 from_PRP the_AT0 time_NN1 series_NN0 would_VM0 further_AV0 refine_VVI these_DT0 estimates_NN2 ._SENT 
4._CRD CONCLUSIONS_NN2 
This_DT0 study_NN1 utilized_VVD research-grade_AJ0 and_CJC trace-level_AJ0 instrumentation_NN1 to_TO0 maximize_VVI the_AT0 potential_AJ0 air_NN1 quality_NN1 insights_NN2 from_PRP the_AT0 data_NN0 through_PRP careful_AJ0 siting_NN1 and_CJC sustained_AJ0 collection_NN1 of_PRF high_AJ0 time-resolution_NN1 data_NN0 ._SENT Comparison_NN1 of_PRF the_AT0 R2PIER_AJ0 site_NN1 against_PRP a_AT0 nearby_AJ0 regulatory_AJ0 monitoring_NN1 site_NN1 revealed_VVD correlation_NN1 in_PRP measured_AJ0 PM2.5_NN1 and_CJC BC_AV0 ._SENT Although_CJS TEUs_NP0 increased_VVD and_CJC ship_NN1 activity_NN1 (_PUL vessel_NN1 pings_NN2 )_PUR did_VDD not_XX0 markedly_AV0 change_VVI ,_PUN NTA_NP0 analysis_NN1 indicated_VVD decreases_NN2 of_PRF SO2_NN1 ,_PUN NOx_NP0 ,_PUN and_CJC BC_AV0 associated_VVN with_PRP port-related_AJ0 geographic_AJ0 areas_NN2 when_CJS comparing_VVG the_AT0 last_ORD 5_CRD quarters_NN2 measured_VVN to_PRP the_AT0 first_ORD 5_CRD quarters_NN2 ._SENT The_AT0 trends_NN2 indicated_VVN by_PRP NTA_NP0 analysis_NN1 were_VBD directionally_AV0 consistent_AJ0 with_PRP "_PUQ port-wide_AJ0 "_PUQ emission_NN1 inventory_NN1 changes_NN2 over_PRP 2012_CRD –_PUN 2015_CRD for_PRP SO2_CRD (_PUL PANYNJ_NP0 ,_PUN 2019b_NP0 )_PUR and_CJC both_DT0 analyses_NN2 found_VVD relatively_AV0 less_DT0 change_NN1 in_PRP NOx_NP0 although_CJS in_PRP differing_AJ0 directions_NN2 ._SENT This_DT0 comparison_NN1 is_VBZ limited_VVN ,_PUN as_CJS this_DT0 study_NN1 's_POS NTA_NN1 analysis_NN1 emphasizes_VVZ geographic_AJ0 areas_NN2 surrounding_VVG the_AT0 monitoring_NN1 site_NN1 position_NN1 and_CJC the_AT0 in_PRP situ_NN1 monitoring_NN1 data_NN0 may_VM0 be_VBI affected_VVN by_PRP sources_NN2 outside_PRP the_AT0 scope_NN1 of_PRF the_AT0 Port_NP0 Authority_NN1 's_POS inventory_NN1 (_PUL e.g._AV0 ,_PUN emissions_NN2 related_VVN to_PRP activities_NN2 from_PRP privately-owned_AJ0 terminals_NN2 )_PUR ._SENT 
As_CJS air_NN1 monitoring_NN1 rates_NN2 increase_VVB with_PRP the_AT0 evolution_NN1 of_PRF air_NN1 monitoring_NN1 technology_NN1 (_PUL e.g._AV0 ,_PUN Snyder_NP0 et_NP0 al._NP0 ,_PUN 2013_CRD )_PUR ,_PUN retention_NN1 and_CJC analysis_NN1 of_PRF high_AJ0 time_NN1 resolution_NN1 air_NN1 monitoring_NN1 data_NN0 may_VM0 enable_VVI the_AT0 isolation_NN1 of_PRF local_AJ0 emission_NN1 signals_NN2 ._SENT Coupled_AJ0 measurements_NN2 of_PRF directly_AV0 emitted_AJ0 pollutants_NN2 and_CJC wind_NN1 ,_PUN along_AVP with_PRP monitor_NN1 siting_NN1 to_TO0 minimize_VVI collinearity_NN1 in_PRP sources_NN2 ,_PUN increases_VVZ the_AT0 likelihood_NN1 of_PRF resolving_VVG geographic_AJ0 source_NN1 emission_NN1 areas_NN2 influencing_VVG the_AT0 measurements_NN2 and_CJC gaining_VVG insight_NN1 into_PRP the_AT0 impacts_NN2 of_PRF emission_NN1 reduction_NN1 efforts_NN2 ._SENT 
