Transportation's Impact: Air Pollution And Our Health

Transportation is a significant contributor to air pollution, with cars, trucks, and buses powered by fossil fuels being the primary culprits. These vehicles emit harmful pollutants such as nitrogen oxides, particulate matter, and carbon monoxide, which have adverse effects on human health and the environment. The issue is particularly pressing in congested urban areas and communities near ports and freight corridors, where vulnerable groups like Latinos, Blacks, and lower-income households bear the brunt of exposure to dangerous air pollution. While electric vehicles, improved fuel technologies, and public transportation are potential solutions, transitioning to cleaner and more sustainable transport options remains a challenge that requires collective effort and policy support.

Cars, trucks, and buses powered by fossil fuels

Cars, trucks, and buses are major sources of air pollution, particularly when powered by fossil fuels. The combustion of fossil fuels, such as gasoline and diesel, releases a range of harmful pollutants into the atmosphere. These emissions contribute significantly to global warming and climate change, with transport being the largest emitter of heat-trapping gases.

Carbon dioxide (CO2) is one of the primary greenhouse gases emitted by vehicles, and it has a significant impact on the planet's climate. However, as Dr Joel Schwartz, a professor at Harvard Chan School, points out, the health impacts of other pollutants emitted alongside CO2 are often overlooked. These pollutants include nitrogen oxides, carbon monoxide, and volatile organic compounds (VOCs).

Nitrogen oxides (NOx) are reddish-brown gases that irritate the lungs and eyes. They are formed when nitrogen in the air reacts with oxygen during the combustion process. NOx contributes to the formation of ground-level ozone, a major component of smog, which irritates the respiratory system, causing coughing, choking, and reduced lung capacity.

Carbon monoxide (CO) is a colorless, odorless, and poisonous gas that is also emitted by vehicles. It forms when fossil fuels, such as gasoline, are burned. CO can be harmful even in small amounts, as it combines with blood and impairs its ability to transport oxygen, leading to serious health consequences, including damage to lung tissue and the exacerbation of respiratory diseases such as asthma.

VOCs, including toxic air pollutants like benzene, acetaldehyde, and 1,3-butadiene, are also released from vehicle tailpipes. VOCs can react with nitrogen oxides in the presence of sunlight to form ground-level ozone, further contributing to smog and air pollution. Additionally, VOCs are linked to various types of cancer.

The impact of these emissions on health is significant. In 2018, fossil fuel pollution was responsible for an estimated 8.7 million deaths globally, with India alone accounting for nearly 2.5 million deaths among those aged over 14. Thousands of children under the age of five also die each year from respiratory infections attributed to fossil fuel pollution.

Reducing emissions from cars, trucks, and buses is crucial to improving air quality and mitigating climate change. This can be achieved through the adoption of zero-emission vehicles (ZEVs), such as electric cars, and the implementation of policies that prioritize public transport, bicycles, and pedestrian movement over private vehicle use.

Aircraft emissions

Aviation emissions have been increasing faster than any other mode of transport, more than doubling between 1990 and 2019. In 1990, aviation emissions accounted for 1.5% of all European emissions, but by 2019, this figure had risen to 4.7%. The sector is expected to fully recover from the Covid-19 pandemic as early as 2024, and if left unmitigated, aviation emissions could more than double by 2050 compared to 2019 levels.

The increase in aviation emissions is driven by rising demand for air travel and technological improvements. As incomes rise globally, more people will be able to afford to fly, leading to a projected continued increase in demand for aviation. Additionally, improvements in energy efficiency have slowed in recent years, and aviation remains one of the hardest sectors to decarbonize.

To address the issue of growing aviation emissions, several solutions are being explored. One approach is the development of zero-emissions aircraft, such as hydrogen or electric planes, which can help reduce emissions, especially for shorter ranges. Additionally, alternative fuels like e-fuels, including power-to-liquid and e-kerosene, have the potential to significantly reduce emissions from the aviation sector. However, they require large amounts of renewable energy, and their effectiveness depends on the source of CO2 used in their production.

Another solution is the implementation of global measures and policies to reduce emissions. For example, the EU's ReFuelEU initiative aims to phase out allowances for the aviation industry and promote the use of sustainable aviation fuels (SAFs). The EU ETS text also includes a provision for airlines to monitor non-CO2 emissions for all flights departing the EU from 2025. Furthermore, individual countries like France, Norway, and Sweden have already mandated the use of SAFs or set targets for their adoption.

Sulphur emissions from ships

Transportation is a significant contributor to air pollution, with road transport being the largest contributor to climate change within the transport sector. Cars, trucks, and buses powered by fossil fuels are major culprits, and while electric cars are being built to reduce emissions, the number of vehicles on the road continues to increase, along with their usage.

Among the various modes of transportation, ships are notable emitters of sulphur, which significantly impacts air quality. Ships travelling internationally from port to port emit pollutants during their voyage, contributing to both air and water pollution. The sulphur compounds emitted by ships oxidize in the atmosphere to form sulphates, which, along with nitrogen compounds, deplete the ozone layer.

To address ship emissions, the International Maritime Organization (IMO) implemented regulations in 2020 mandating the use of low-sulphur fuel by all ships worldwide. This has resulted in a welcome decrease in sulphur dioxide (SO2) emissions, improving public health. The decline in SO2 emissions is expected to continue, especially with the faster phase-out of fossil fuels.

However, the reduction in sulphur emissions from ships has had an unintended consequence. Sulphur particles in ship exhaust fumes previously counteracted some of the warming effects of greenhouse gases. With the decrease in sulphur emissions, there has been a slight boost in ocean surface temperatures, contributing to global warming.

While the reduction in sulphur oxide emissions from ships is beneficial for public health, it has highlighted the complexity of addressing climate change. The trade-off between cleaner air and potential increases in global temperatures underscores the need for a comprehensive approach to mitigating the environmental impact of transportation.

Tyre and brake wear

The problem of tyre and brake wear pollution is particularly acute in urban areas, where road traffic is a major source of air pollution. As cars, trucks, and buses burn fossil fuels, they emit harmful pollutants such as nitrogen oxides (NOx), particulate matter, and carbon monoxide (CO). These emissions have been linked to adverse impacts on nearly every organ system in the body, with vulnerable populations such as children, the elderly, and people of colour being disproportionately affected.

One way to reduce tyre and brake wear pollution is to transition to electric vehicles (EVs). EVs produce less brake wear and similar tyre wear compared to traditional petrol and diesel vehicles. Regenerative braking in EVs, where the electric motor works in reverse to convert kinetic energy into electricity, reduces brake use and wear. Additionally, driving EVs in eco mode can help extend tyre lifespan. Cities with a high uptake of EVs have already seen improvements in air quality due to reduced particulate matter from exhausts, tyres, and brakes.

However, the increasing weight of EVs due to their large batteries can also put more strain on tyres, potentially causing more pollution. Scientists suggest that shifting tyre materials to natural or non-fossil fuel sources may be a solution. Some companies are experimenting with sustainable alternatives, such as dandelions, to the traditional synthetic rubber derived from crude oil.

While regulations and innovations can help mitigate the problem, tyre and brake wear remains a significant contributor to air pollution from transportation. Addressing this issue is crucial for improving air quality and reducing the health risks associated with exposure to particulate matter pollution.

Environmental noise exposure

The impact of noise pollution goes beyond annoyance and discomfort. Long-term exposure to noise above certain levels can lead to adverse health effects, including sleep disturbance, cardiovascular and metabolic issues, and cognitive impairment in children. It can also affect wildlife, causing various physical and behavioural issues and increasing stress levels. For example, road traffic noise can disrupt the communication of frogs and songbirds, while underwater noise from shipping can impact the ability of whales to find food and communicate.

In Europe, about 95 million people are exposed to harmful levels of road traffic noise, with at least 20% of the urban population in many cities affected. This percentage can reach 50% or more in some urban areas. It is estimated that long-term exposure to transport noise causes approximately 11,000 premature deaths and 40,000 new cases of ischaemic heart disease in the EU.

Transportation noise and air pollution often share common sources, including aircraft, trains, and road vehicles, resulting in simultaneous exposure to both types of pollution. Research suggests that the EU faces substantial costs due to noise and air pollution, reaching nearly 1 trillion EUR.

To address environmental noise exposure, the EU has implemented policies and directives under the Zero Pollution Action Plan and the Environmental Noise Directive (END). These measures aim to reduce exposure to noise and mitigate its harmful effects, preserving 'quiet' areas and imposing noise limits on certain vehicles or equipment.

Frequently asked questions