The epidemiological and toxicological evidence on the effects oftransport-related air pollution on health has increased substantially in recent decades. Although this includes epidemiological and toxicological evidence, it is only a fraction ofthe total evidence on the effects on health of urban air pollution.
A review ofthis evidence indicates that transport-related air pollution contributes to an increased risk ofdeath, particularly from cardiopulmonary causes. It increases the risk ofrespiratory symptoms and diseases that are not related to allergies. Experimental research indicates that the effects are linked to changes in the formation of reactive oxygen species, changes in antioxidant defence, and increased inflammation, thus providing some indication of mechanisms ofsusceptibility. Laboratory studies indicate that transport-related air pollution may increase the risk ofdeveloping an allergy and can exacerbate symptoms, particularly in susceptible subgroups. The evidence from population studies, however, does not consistently support this notion. While only a few studies have been conducted on the effects of transport-related air pollution on cardiovascular morbidity, they report a significant increase in the risk of myocardial infarction following exposure. Other studies and the experimental evidence indicate that exposure results in changes in autonomic nervous system regulation and increased inflammatory responses. Afew studies suggest an increased incidence oflung cancer in people with long-term exposure to transport-related air pollution. Some studies suggest that it also causes adverse outcomes in pregnancy, such as premature birth and low birth weight, but the available evidence is inconsistent.
Few reported studies analyse the effects ofspecific interventions, and even fewerfocus on transport-related air pollution. They indicate that reducingthis pollution may directly reduce acute asthma attacks in children and the related medical care. Long-term decreases in air-pollution levels are associated with declines in bronchial hyperreactivity, in the average annual trend in deaths from all causes, and in respiratory and cardiovascular diseases. Such decreases are also associated with gains in life expectancy.
Often, the effects observed in epidemiological studies cannot be attributed to the specific pollution indicator used in the study, but can be attributed to a mixture of pollutants. Fine PM (including black smoke) and ozone are associated with increased risks ofmortality and respiratory morbidity, while exposure to nitrogen dioxide, ozone and PM has been linked to allergic responses. Other indicators ofexposure to transport-related air pollution — such as distance to or residence near major roads and, partly, self-reported traffic intensity at a residence — are associated with several adverse health outcomes.
This accumulated evidence allows the hazards of transport-related air pollution to be identified, but makes only a limited contribution to the qualitative assessment ofits adverse effects on health and to the prediction ofthe benefits ofreducing this part of the total air-pollution mix.
Initial estimates show that tens of thousands of deaths per year are attributable to transport-related air pollution in the Region, similar to the death toll from traffic accidents. The research database still needs improvement, however, to allow a more precise evaluation ofthe effects ofand changes in exposure. More research is needed on the patterns and adverse health effects of population exposure and on the role ofthe different components ofthe pollution mix. The relevance of emissions from various transport-related sources (such as heavy- and light-duty diesel cars) to health issues also needs further investigation. More studies that assess the public health benefits of various measures to improve air quality — particularly through interventions that address transport-related air pollution — are needed to support policies.
Despite the needforfurther research, the expected health benefits thoroughly justify measures to reduce exposure to transport-related air pollution. Traffic management is one ofthe instruments that can significantly reduce the exposure of residents of urban areas. In addition, the integration ofenvironmental and health considerations into urban planning can be improved. In particular, urban planning may aim at integrative measures that lower emission rates, such as the promotion ofhighly efficient, service-oriented and clean public transport and improvements in the flow of traffic. Several technologies show promise in lowering emission levels from conventional vehicles, and their development should be promoted, along with effective control mechanisms (such as mandatory car inspections) for eliminating gross polluters and badly maintained vehicles. Finally, alternative vehicle technologies and fuel substitutes could lead to substantial future reductions in emissions ofhazardous air pollutants.
Was this article helpful?
The human body And Todays chemical infested world. Here is a news flash You are not allergic to pollen, pet dander, or whatever it is that makes your body revolt Rather, your body just can not handle that one thing, what ever it is, anymore, due to the massive barrage of toxic chemicals you and everyone else are ingesting every single day.