Measurements of peroxyacyl nitrates (PANS) in Mexico City: implications for megacity air quality impacts on regional scales

Gaffney, J. S.; Marley, N. A.; Cunningham, Mary M.; Doskey, Paul V.

doi:10.1016/s1352-2310(99)00263-0

Cited by 89 publications

(76 citation statements)

References 20 publications

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“…Absolute modeled concentrations of PAN are comparable in Mexico and Paris, and are significantly higher than in Nashville. The model PAN is approximately 50% lower than the average from an ensemble of measurements at one station in Mexico City (Gaffney et al, 1999). High concentrations of PAN were also reported in model results by Lei et al (2007).…”

Section: Comparison Between Mexico City Parismentioning

confidence: 52%

“…Results for Mexico are similar at 13-14 h and 15-16 h on 4 March, although on 2 March the O 3 -PAN correlation for Mexico showed greater scatter. The measurements from Gaffney et al (1999) showed a loose correlation between PAN and O 3 with an average PAN/O 3 ratio equal to .12 for O 3 above 100 ppb. The model PAN/O 3 is significantly lower (.07) but the measured PAN, O 3 , and PAN/O 3 still fall within the range of measured values.…”

Section: Comparison Between Mexico City Parismentioning

confidence: 90%

“…They found generally good agreement for these species following their adjustment in emission rates. also compared model results with previous measurements of PAN (Gaffney et al, 1999) and total nitric acid (gas phase HNO 3 plus particulate nitrate, Chow et al, 2002). They found that model PAN was lower than the average measurements by a factor of two, while total nitric acid was only slightly underestimated (26%).…”

Section: Model Description and Applicationmentioning

confidence: 95%

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Reactive nitrogen in Mexico City and its relation to ozone-precursor sensitivity: results from photochemical models

Sillman

West

2009

Atmos. Chem. Phys.

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Abstract.We use results of a 3-D photochemistry/transport model for ozone formation in Mexico City during events in 1997 to investigate ambient concentrations of reactive nitrogen in relation to ozone-precursor sensitivity. Previous results from other locations suggest that ratios such as O 3 /NO y and H 2 O 2 /HNO 3 might provide measurement-based indicators for NO x -sensitive or VOC-sensitive conditions. Mexico City presents a different environment due to its high concentrations of VOC and high level of pollutants in general. The model predicts a correlation between PAN and O 3 with relatively high PAN/O 3 (0.07), which is still lower than measured values. The model PAN is comparable with results from a model for Paris but much higher than were found in Nashville in both models and measurements. The difference is due in part to the lower temperature in Mexico City relative to Nashville. Model HNO 3 in Mexico City is unusually low for an urban area and PAN/HNO 3 is very high, probably due to the high ratio of reactivity-weighted VOC to NO x . The model predicts that VOC-sensitive chemistry in Mexico is associated with high NO x , NO y and NO x /NO y and with low O 3 /NO y and H 2 O 2 /HNO 3 , suggesting that these indicators work well for Mexico City. The relation between ozone-precursor sensitivity and either O 3 /NO z or O 3 /HNO 3 is more ambiguous. VOC-sensitive conditions are associated with higher O 3 /HNO 3 than would be found in NO x -sensitive conditions, but model O 3 /HNO 3 associated with both NO xsensitive and VOC-sensitive chemistry is higher in Mexico than in other cities. The model predicts a mixed pattern of ozone-precursor sensitivity in Mexico City, with VOCsensitive conditions in the morning and NO x -sensitive in the afternoon, in contrast to results from other models for more recent events that predicted strongly VOC-sensitive conditions throughout the day. The difference in predicted ozoneCorrespondence to: S. Sillman (sillman@umich.edu) precursor sensitivity is most likely due to different emission rates and to changes in emissions over time. The model with mixed sensitivity predicts much lower ambient NO x and NO x /NO y than the strongly VOC-sensitive model.

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Section: Comparison Between Mexico City Parismentioning

confidence: 52%

Section: Comparison Between Mexico City Parismentioning

confidence: 90%

Section: Model Description and Applicationmentioning

confidence: 95%

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Reactive nitrogen in Mexico City and its relation to ozone-precursor sensitivity: results from photochemical models

Sillman

West

2009

Atmos. Chem. Phys.

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“…Gaffney et al (1999), Tie et al (2009), Li et al (2011) and Shrivastava et al (2011) for Mexico City; Hodnebrog et al (2011) for European megacities and Cairo; Lin et al (2010) for Beijing and Pearl River extended areas). These investigations clearly showed the importance of megacities as pollution sources for the surrounding areas; their contribution to regional scale ozone (O 3 ) and secondary aerosols during LRT and to peroxyacetyl nitrate (PAN) produced in the megacities extended areas and downwind (Gaffney et al, 1999;Molina et al, 2010). Large amounts of carbon monoxide (CO) are transported from urban centers to the downwind areas and contribute significantly to the hydroxyl (OH) reactivity in the city and along the outflow (Tie et al, 2009: MIRAGE-Mex project (Megacities Impact on Regional and Global Environments-Mexico City Case Study)).…”

Section: Introductionmentioning

confidence: 99%

Impacts of East Mediterranean megacity emissions on air quality

İm

Kanakidou

2012

Atmos. Chem. Phys.

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Abstract.Megacities are large urban agglomerations with intensive anthropogenic emissions that have significant impacts on local and regional air quality. In the present mesoscale modeling study, the impacts of anthropogenic emissions from the Greater Istanbul Area (GIA) and the Greater Athens Area (GAA) on the air quality in GIA, GAA and the entire East Mediterranean are quantified for typical wintertime (December 2008) and summertime (July 2008) conditions. They are compared to those of the regional anthropogenic and biogenic emissions that are also calculated. Finally, the efficiency of potential country-based emissions mitigation in improving air quality is investigated.The results show that relative contributions from both cities to surface ozone (O 3 ) and aerosol levels in the cities' extended areas are generally higher in winter than in summer. Anthropogenic emissions from GIA depress surface O 3 in the GIA by ∼ 60 % in winter and ∼ 20 % in summer while those from GAA reduce the surface O 3 in the GAA by 30 % in winter and by 8 % in summer. GIA and GAA anthropogenic emissions contribute to the fine particulate matter (PM 2.5 ) levels inside the cities themselves by up to 75 % in winter and by 50 % (GIA) and ∼ 40 % (GAA), in summer. GIA anthropogenic emissions have larger impacts on the domain-mean surface O 3 (up to 1 %) and PM 2.5 (4 %) levels compared to GAA anthropogenic emissions (< 1 % for O 3 and ≤ 2 % for PM 2.5 ) in both seasons. Impacts of regional anthropogenic emissions on the domain-mean surface pollutant levels (up to 17 % for summertime O 3 and 52 % for wintertime fine particulate matter, PM 2.5 ) are much higher than those from Istanbul and Athens together (∼ 1 % for O 3 and ∼ 6 % for PM 2.5 , respectively). Regional biogenic emissions are found to limit the production of secondary inorganic aerosol species in summer up to 13 % (non-sea-salt sulfate (nss-SO 2− 4 ) in rural Athens) due to their impact on oxidant levels while they have negligible impact in winter.Finally, the responses to country-based anthropogenic emission mitigation scenarios inside the studied region show increases in O 3 mixing ratios in the urban areas of GIA and GAA, higher in winter (∼ 13 % for GIA and 2 % for GAA) than in summer (∼ 7 % for GIA and < 1 % for GAA). On the opposite PM 2.5 concentrations decrease by up to 30 % in GIA and by 20 % in GAA with the highest improvements computed for winter. The emission reduction strategy also leads to domain-wide decreases in most primary pollutants like carbon monoxide (CO) or nitrogen oxides (NO x ) for both seasons. The results show the importance of long range transport of pollutants for the air quality in the East Mediterranean. Thus, improvements of air quality in the East Mediterranean require coordinated efforts inside the region and beyond.

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“…Many of them were based on measurements within and outside of the urban plumes from particular cities (Freney et al, 2014;Lin et al, 1996;Gaffney et al, 1999;Molina et al, 2010;Kuhn et al, 2010;Wang et al, 2006). There has also been model-based efforts to estimate the cities fingerprint on the atmospheric chemistry across multiple scales: on a global scale, Lawrence et al (2007), Lawrence (2009), Folberth et al (2010) and Stock et al (2013) gave estimates on the city emissions impact on the surrounding environment.…”

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confidence: 99%

On the long-term impact of emissions from central European cities on regional air quality

2016

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Abstract. For the purpose of qualifying and quantifying the impact of urban emission from Central European cities on the present-day regional air quality, the regional climate model RegCM4.2 was coupled with the chemistry transport model CAMx, including two-way interactions. A series of simulations was carried out for the 2001-2010 period either with all urban emissions included (base case) or without considering urban emissions. Further, the sensitivity of ozone production to urban emissions was examined by performing reduction experiments with −20 % emission perturbation of NO x and/or non-methane volatile organic compounds (NMVOC).The modeling system's air quality related outputs were evaluated using AirBase, and EMEP surface measurements showed reasonable reproduction of the monthly variation for ozone (O 3 ), but the annual cycle of nitrogen dioxide (NO 2 ) and sulfur dioxide (SO 2 ) is more biased. In terms of hourly correlations, values achieved for ozone and NO 2 are 0.5-0.8 and 0.4-0.6, but SO 2 is poorly or not correlated at all with measurements (r around 0.2-0.5). The modeled fine particulates (PM 2.5 ) are usually underestimated, especially in winter, mainly due to underestimation of nitrates and carbonaceous aerosols.European air quality measures were chosen as metrics describing the cities emission impact on regional air pollution. Due to urban emissions, significant ozone titration occurs over cities while over rural areas remote from cities, ozone production is modeled, mainly in terms of number of exceedances and accumulated exceedances over the threshold of 40 ppbv. Urban NO x , SO 2 and PM 2.5 emissions also significantly contribute to concentrations in the cities themselves (up to 50-70 % for NO x and SO 2 , and up to 60 % for PM 2.5 ), but the contribution is large over rural areas as well (10-20 %). Although air pollution over cities is largely determined by the local urban emissions, considerable (often a few tens of %) fraction of the concentration is attributable to other sources from rural areas and minor cities. For the case of Prague (Czech Republic capital), it is further shown that the inter-urban interference between large cities does not play an important role which means that the impact on a chosen city of emissions from all other large cities is very small. At last, it is shown that to achieve significant ozone reduction over cities in central Europe, the emission control strategies have to focus on the reduction of NMVOC, as reducing NO x (due to suppressed titration) often leads to increased O 3 . The influence over rural areas is however always in favor of improved air quality, i.e. both NO x and/or NMVOC reduction ends up in decreased ozone pollution, mainly in terms of exceedances.

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Measurements of peroxyacyl nitrates (PANS) in Mexico City: implications for megacity air quality impacts on regional scales

Cited by 89 publications

References 20 publications

Reactive nitrogen in Mexico City and its relation to ozone-precursor sensitivity: results from photochemical models

Reactive nitrogen in Mexico City and its relation to ozone-precursor sensitivity: results from photochemical models

Impacts of East Mediterranean megacity emissions on air quality

On the long-term impact of emissions from central European cities on regional air quality

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