Computer modeling studies of the impact of vehicle exhaust emission controls on photochemical air pollution formation in the United Kingdom

Derwent, Richard G.; Hov, Ø.

doi:10.1021/es60171a013

Cited by 41 publications

(15 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Values of a i and b• were determined for 26 separate photochemical processes by plotting the logarithm of J against sec 0 and have been tabulated by Hough [1986]. The use of this expression has been discussed by Derwent and Hov [1979]. In practice, this meant that separate photolysis rates were available for most species.…”

Section: Ji = Ai Exp (-B I Sec 0)mentioning

confidence: 99%

An intercomparison of mechanisms for the production of photochemical oxidants

Hough¹

1988

J. Geophys. Res.

View full text Add to dashboard Cite

Twenty different chemical mechanisms used in studies of the formation of photochemical oxidants have been compared. In order to concentrate on the differences in the hydrocarbon chemistry, these mechanisms were modified so that each contained the same inorganic processes and so that the rate coefficients for the hydrocarbon degradation reactions were the same in most cases. The mechanisms were all implemented in a model to study the formation of photochemical oxidants downwind of London during midsummer, clear‐sky, anticyclonic conditions. The same emissions inventory and meteorological parameters were used in each case. The mechanisms published since 1984 all produced similar results for ozone and nitric acid. The standard deviations of these concentrations were some 2–3 times greater when the whole set of results was considered. The concentrations of hydrogen peroxide and peroxyacylnitrates were much more variable, with concentrations varying by up to a factor of 2 for the recent mechanisms and with effectively no agreement over the whole set. This suggests that for these species, any agreement between observations and calculations which is within a factor of 2 is as good as can be expected and that model calculations cannot be verified to a greater degree of accuracy. The representation of hydrocarbon emissions in photochemical models and the ways in which large numbers of known atmospheric species are represented by a limited number of model variables clearly require further attention before confidence can be claimed in the model results for a wide range of photochemically generated secondary pollutants.

show abstract

Section: Ji = Ai Exp (-B I Sec 0)mentioning

confidence: 99%

An intercomparison of mechanisms for the production of photochemical oxidants

Hough¹

1988

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…About 300 reactions were required to describe the degradation pathways. A detailed discussion of the scheme was given by Derwent and Hov (1980a). Later revisions were based on the work by Atkinson et al (1979Atkinson et al ( , 1982, Hampson and Garvin (1978), NASA (1982) and McRae et aL (1982).…”

Section: Chemicai Processes Affecting Panmentioning

confidence: 99%

“…-How is the persistence of PAN compared with ozone? -How is PAN affected by new emissions of nitrogen oxides (NOx), hydrocarbons (HC) The model applied was developed by Derwent and Hov (1979, 1980a. An illustration of the model is given in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Modelling of the long-range transport of peroxyacetylnitrate to Scandinavia

Hov

1984

J Atmos Chem

View full text Add to dashboard Cite

Model calculations and field measurements have shown that when air masses accumulate emissions of hydrocarbons and nitrogen oxides from sources in continental Europe and then move towards Scandinavia without any synoptic scale break-up of the atmospheric boundary layer (e.g. frontal passages), elevated PAN concentrations in southern Norway or Sweden in the range 1-5 ppb may be caused by long-range transport. The model calculations showed that over sea, the persistence of PAN was comparable to that of ozone in an ageing air mass when the temperatures were fairly low (5-10°C). At higher temperatures the thermal decomposition of PAN made the compound less persistent than ozone. Over land, the situation may be different since the ground removal is typically three times more efficient for ozone than for PAN. According to the model, the concentration of PAN did not change very much when an ageing air mass was exposed to moderate emissions of hydrocarbons, nitrogen oxides, or both. The concentration of PAN decreased less than the concentration of ozone when an ageing air mass was exposed to high emissions of nitrogen oxides.

show abstract

“…The effects of various control strategies are shown, viz: 20% reduction of HC emissions and 50% reduction of both HC and NO X emissions together with a case of no reductions. 8 According to the AERE Harwell model, HC control is much more efficient than combined HC and NO* controls from the standpoint of the generation of photochemical pollution. In particular, the results for OH are interesting, where more OH is generated when the emissions of NO X and HC are cut by 50%, than in the standard case.…”

Section: The Significance Of Model Predictions Of the Effects Of Diffmentioning

confidence: 99%