Emma J. Hutchinson

The transport sector as a source of air pollution

Transport first became a significant source of air pollution after the problems of sooty smog from coal combustion had largely been solved in western European and North American cities. Since then, emissions from road, air, rail and water transport have been partly responsible for acid deposition, stratospheric ozone depletion and climate change. Most recently, road traffic exhaust emissions have been the cause of much concern about the effects of urban air quality on human health and tropospheric ozone production. This article considers the variety of transport impacts on the atmospheric environment by reviewing three examples: urban road traffic and human health, aircraft emissions and global atmospheric change, and the contribution of sulphur emissions from ships to acid deposition. Each example has associated with it a different level of uncertainty, such that a variety of policy responses to the problems are appropriate, from adaptation through precautionary emissions abatement to cost-benefit analysis and optimised abatement. There is some evidence that the current concern for road transport contribution to urban air pollution is justified, but aircraft emissions should also give cause for concern given that air traffic is projected to continue to increase. Emissions from road traffic are being reduced substantially by the introduction of technology especially three-way catalysts and also, most recently, by local traffic reduction measures especially in western European cities. In developing countries and Eastern Europe, however, there remains the possibility of great increase in car ownership and use, and it remains to be seen whether these countries will adopt measures now to prevent transport-related air pollution problems becoming severe later in the 21st Century

Lung cancer risk after exposure to polycyclic aromatic hydrocarbons: A review and meta-analysis

Typical polycyclic aromatic hydrocarbon mixtures are established lung carcinogens, but the quantitative exposure–response relationship is less clear. To clarify this relationship we conducted a review and meta-analysis of published reports of occupational epidemiologic studies. Thirty-nine cohorts were included. The average estimated unit relative risk (URR) at 100 μg/m3 years benzo[a]pyrene was 1.20 [95% confidence interval (CI), 1.11–1.29] and was not sensitive to particular studies or analytic methods. However, the URR varied by industry. The estimated means in coke ovens, gasworks, and aluminum production works were similar (1.15–1.17). Average URRs in other industries were higher but imprecisely estimated, with those for asphalt (17.5; CI, 4.21–72.78) and chimney sweeps (16.2; CI, 1.64–160.7) significantly higher than the three above. There was no statistically significant variation of URRs within industry or in relation to study design (including whether adjusted for smoking), or source of exposure information. Limited information on total dust exposure did not suggest that dust exposure was an important confounder or modified the effect. These results provide a more secure basis for risk assessment than was previously available.

Changes in platinum concentrations in soils and dusts from UK cities

Vehicle exhaust catalysts have been fitted to all new cars in the UK since January 1993, in order to comply with EU Stage I limits (EC Directive 91/441/EEC) on emissions of carbon monoxide, hydrocarbons and nitrogen oxides (N02 nitrogen dioxide and NO nitric oxide). A typical catalyst contains 1–3 g of platinum group metal, housed in a stainless steel box. Catalysts are designed to operate for at least 80,000 km, and their numbers are increasing worldwide, therefore Pt losses are of general environmental interest. Validated data are needed to determine concentrations in environmental media in order that potential health risks and environmental impacts of this source of Pt may be assessed.

Recent increases in platinum metals in the environment from vehicle catalytic converters

Abstract The natural and anthropogenic sources of platinum metals in the environment are reviewed with particular emphasis on platinum from vehicle exhaust catalysts (VECs). Reported increases world-wide in platinum metal concentrations in a number of environmental media over recent time are discussed. Estimations of the emission rates for platinum from petrol (gasoline) powered cars in the literature have been made from both test rig and environmental considerations. Using such emission rates, it is estimated that the total input of Pt from UK traffic during the years 1993–1999 varied between about 250 kg and 120 kg. World-wide, the annual input into the environment is estimated to be between 0·5 × 106 and 1·5 × 106 kg. The health implications of such inputs of platinum metals into the environment are considered. At present, there is no evidence for adverse effects on human health, although the effects of long-term inhalation and ingestion of PGE containing particulates is not known. Potential impacts on the environment, in particular microflora, are also important, since it is known that some PGE compounds have effects on micro-organisms at very low concentrations.

Chapter 6 The transport sector as a source of air pollution

Abstract Transport first became a significant source of air pollution after the problems of sooty smog from coal combustion had largely been solved in western European and North American cities. Since then, emissions from road, air, rail and water transport have been partly responsible for acid deposition, stratospheric ozone depletion and climate change. Most recently, road traffic exhaust emissions have been the cause of much concern about the effects of urban air quality on human health and tropospheric ozone production. This article considers the variety of transport impacts on the atmospheric environment by reviewing three examples: urban road traffic and human health, aircraft emissions and global atmospheric change, and the contribution of sulphur emissions from ships to acid deposition. Each example has associated with it a different level of uncertainty, such that a variety of policy responses to the problems are appropriate, from adaptation through precautionary emissions abatement to cost-benefit analysis and optimised abatement. There is some evidence that the current concern for road transport contribution to urban air quality is justified, but aircraft emissions should also give cause for concern given that air traffic is projected to continue to increase. Emissions from road traffic are being reduced substantially by the introduction of technology especially three-way catalysts and also, most recently, by local traffic reduction measures especially in western European cities. In developing countries and Eastern Europe, however, there remains the possibility of great increase in car ownership and use, and it remains to be seen whether these countries will adopt measures now to prevent transport-related air pollution problems becoming severe later in the 21 st Century.

Comparison of built environment adaptations to heat exposure and mortality during hot weather, West Midlands region, UK

There is growing recognition of the need to improve protection against the adverse health effects of hot weather in the context of climate change. We quantify the impact of the Urban Heat Island (UHI) and selected adaptation measures made to dwellings on temperature exposure and mortality in the West Midlands region of the UK. We used 1) building physics models to assess indoor temperatures, initially in the existing housing stock and then following adaptation measures (energy efficiency building fabric upgrades and/or window shutters), of representative dwelling archetypes using data from the English Housing Survey (EHS), and 2) modelled UHI effect on outdoor temperatures. The ages of residents were combined with evidence on the heat-mortality relationship to estimate mortality risk and to quantify population-level changes in risk following adaptations to reduce summertime heat exposure. Results indicate that the UHI effect accounts for an estimated 21% of mortality. External shutters may reduce heat-related mortality by 30-60% depending on weather conditions, while shutters in conjunction with energy-efficient retrofitting may reduce risk by up to 52%. The use of shutters appears to be one of the most effective measures providing protection against heat-related mortality during periods of high summer temperatures, although their effectiveness may be limited under extreme temperatures. Energy efficiency adaptations to the dwellings and measures to increase green space in the urban environment to combat the UHI effect appear to be less beneficial for reducing heat-related mortality.

Vehicle exhaust catalysts in Great Britain: an environmental and economic analysis

Abstract This paper presents a summary of research conducted on the short-term health benefits arising from the introduction of vehicle exhaust catalysts (VECs) to petrol-fuelled cars in the UK. We carried out an evaluation of the environmental and health benefits from a reduction in emissions through this mandated technology against its costs, for urban areas of Great Britain. We made an ex post assessment – based on available data to 1998 – and an ex ante assessment – projected to 2005, when full penetration of VECs into the car fleet is anticipated. The results indicate substantial health benefits from VECs that are likely to exceed their costs significantly: by 1998, when no more than half the car fleet had catalysts installed, the net societal health benefits were around £500 million, while by 2005, the benefits could reach £2 billion. We also found through environmental surveys, that although lead concentrations in road dusts have fallen by 50% in urban areas, platinum accumulations near roads have risen up to 90-fold higher than natural background levels. This suggests that although as yet there is no evidence of adverse health effects from platinum, further monitoring may be warranted.