Six ‘new’ episodes of trans-Pacific transport of air pollutants

Jaffe, Dan; McKendry, Ian G.; Anderson, T. L.; Price, H. U.

doi:10.1016/s1352-2310(02)00862-2

Cited by 264 publications

(249 citation statements)

References 48 publications

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“…2). Spring contributions are over 40 ppb across the western US, which is the region most influenced by pollution transported from Asia (Jaffe et al, 2003;Zhang et al, 2011;Lin et al, 2012a;Emery et al, 2012). In particular, high-O 3 events over the high terrain in the western US have been linked to intercontinental transport and stratospheric intrusions (Lin et al, 2012a, b).…”

Section: Bc Ozone Contributions To Surface Ozonementioning

confidence: 99%

“…Intercontinental ozone (O 3 ) transport extends the geographic range of O 3 air pollution impacts and makes local air pollution management more difficult (Jaffe et al, 2003;Emery et al, 2012). The Air Quality Model Evaluation International Initiative (AQMEII) aims to better understand uncertainties in regional-scale model predictions and foster continued model improvement by providing a collaborative, cross-border forum for model development and evaluation in North America and Europe (Galmarini and Rao, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Modeling intercontinental transport of ozone in North America with CAMx for the Air Quality Model Evaluation International Initiative (AQMEII) Phase 3

et al. 2017

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Abstract. Intercontinental ozone (O 3 ) transport extends the geographic range of O 3 air pollution impacts and makes local air pollution management more difficult. Phase 3 of the Air Quality Modeling Evaluation International Initiative (AQMEII-3) is examining the contribution of intercontinental transport to regional air quality by applying regionalscale atmospheric models jointly with global models. We investigate methods for tracing O 3 from global models within regional models. The CAMx photochemical grid model was used to track contributions from boundary condition (BC) O 3 over a North American modeling domain for calendar year 2010 using a built-in tracer module called RTCMC. RTCMC can track BC contributions using chemically reactive tracers and also using inert tracers in which deposition is the only sink for O 3 . Lack of O 3 destruction chemistry in the inert tracer approach leads to overestimation biases that can exceed 10 ppb. The flexibility of RTCMC also allows tracking O 3 contributions made by groups of vertical BC layers. The largest BC contributions to seasonal average daily maximum 8 h averages (MDA8) of O 3 over the US are found to be from the mid-troposphere (over 40 ppb) with small contributions (a few ppb) from the upper troposphere-lower stratosphere. Contributions from the lower troposphere are shown to not penetrate very far inland. Higher contributions in the western than the eastern US, reaching an average of 57 ppb in Denver for the 30 days with highest MDA8 O 3 in 2010, present a significant challenge to air quality management approaches based solely on local or US-wide emission reductions. The substantial BC contribution to MDA8 O 3 in the Intermountain West means regional models are particularly sensitive to any biases and errors in the BCs. A sensitivity simulation with reduced BC O 3 in response to 20 % lower emissions in Asia found a near-linear relationship between the BC O 3 changes and surface O 3 changes in the western US in all seasons and across the US in fall and winter. However, the surface O 3 decreases are small: below 1 ppb in spring and below 0.5 ppb in other seasons.

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Section: Bc Ozone Contributions To Surface Ozonementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling intercontinental transport of ozone in North America with CAMx for the Air Quality Model Evaluation International Initiative (AQMEII) Phase 3

et al. 2017

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“…Although domestic sources are important, we have previously shown (Park et al, 2004) that transboundary transport of anthropogenic aerosols emitted outside the USA limits the potential for these areas to achieve natural visibility conditions as sought by the Regional Haze Rule (RHR) of the US Environmental Protection Agency (US EPA, 2003). Transboundary pollution includes contributions from Canada and Mexico, but also from Asia (Jaffe et al, 1999(Jaffe et al, , 2003Bertschi et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Regional visibility statistics in the United States: Natural and transboundary pollution influences, and implications for the Regional Haze Rule

Park

Jacob

Kumar

et al. 2006

Atmospheric Environment

225

186

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The Regional Haze Rule of the US Environmental Protection Agency mandates reduction in US anthropogenic emissions to achieve linear improvement of visibility in wilderness areas over the 2004-18 period toward an endpoint of natural visibility conditions by 2064. Linear improvement is to apply to the mean visibility degradation on the statistically 20% worst days, measured as a Haze Index in units of deciviews (log of aerosol extinction). We use a global chemical transport model (GEOS-Chem) with 11 Â 11 horizontal resolution to simulate present-day visibility statistics in the USA, compare them to observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE) surface network, and provide natural and background visibility statistics for application of the Regional Haze Rule. Background is defined by suppression of US anthropogenic emissions but allowance for present-day foreign emissions and associated import of pollution. Our model is highly successful at reproducing the observed variability of visibility statistics for present-day conditions, including the low tail of the frequency distribution that is most representative of natural or background conditions. We find considerable spatial and temporal variability in natural visibility over the USA, especially due to fires in the west. A major uncertainty in estimating natural visibility is the sensitivity of biogenic organic aerosol formation to the availability of preexisting anthropogenic aerosol. Background visibility is more variable than natural visibility and the 20% worst days show large contributions from Canadian and Mexican pollution. Asian pollution, while degrading mean background visibility, is relatively less important on the worst days. Recognizing the influence of uncontrollable transboundary pollution in the Regional Haze Rule would substantially decrease the schedule of emission reductions required in the 2004-18 implementation phase. Meaningful application of the Rule in the future will require projections of future trends in foreign anthropogenic emissions, wildfire frequency, and climate variables. r

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“…40,41 The arrival height of air mass should be multiple within or just above the local atmospheric boundary layer (ABL) in order to get the air mass which reflects the possibility of LRAT. 42 The ABL is generally below 1 km in urban cities; however, it should be much higher and can even extend to almost 3 km above the ground surface in the Tibetan Plateau. 43 Consequently, 5 day back trajectories at the Hailuogou Station were calculated at 100, 500, and 3000 m above ground level at 12 h intervals for each day for more than a year (May 2011−July 2012, including the entire sampling period).…”

Section: ■ Experimental Sectionmentioning

confidence: 96%

Forest Filter Effect versus Cold Trapping Effect on the Altitudinal Distribution of PCBs: A Case Study of Mt. Gongga, Eastern Tibetan Plateau

Liu

Zheng

et al. 2014

Environ. Sci. Technol.

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Mountains are observed to preferentially accumulate persistent organic pollutants (POPs) at higher altitude due to the cold condensation effect. Forest soils characterized by high organic carbon are important for terrestrial storage of POPs. To investigate the dominant factor controlling the altitudinal distribution of POPs in mountainous areas, we measured concentrations of polychlorinated biphenyls (PCBs) in different environmental matrices (soil, moss, and air) from nine elevations on the eastern slope of Mt. Gongga, the highest mountain in Sichuan Province on the Tibetan Plateau. The concentrations of 24 measured PCBs ranged from 41 to 510 pg/g dry weight (dw) (mean: 260 pg/g dw) in the O-horizon soil, 280 to 1200 pg/g dw (mean: 740 pg/g dw) in moss, and 33 to 60 pg/m 3 (mean: 47 pg/m 3 ) in air. Soil organic carbon was a key determinant explaining 75% of the variation in concentration along the altitudinal gradient. Across all of the sampling sites, the average contribution of the forest filter effect (FFE) was greater than that of the mountain cold trapping effect based on principal components analysis and multiple linear regression. Our results deviate from the thermodynamic theory involving cold condensation at high altitudes of mountain areas and highlight the importance of the FFE.

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Six ‘new’ episodes of trans-Pacific transport of air pollutants

Cited by 264 publications

References 48 publications

Modeling intercontinental transport of ozone in North America with CAMx for the Air Quality Model Evaluation International Initiative (AQMEII) Phase 3

Modeling intercontinental transport of ozone in North America with CAMx for the Air Quality Model Evaluation International Initiative (AQMEII) Phase 3

Regional visibility statistics in the United States: Natural and transboundary pollution influences, and implications for the Regional Haze Rule

Forest Filter Effect versus Cold Trapping Effect on the Altitudinal Distribution of PCBs: A Case Study of Mt. Gongga, Eastern Tibetan Plateau

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