Cars: Air Polluters And Ways To Reduce Emissions

Cars are a major contributor to air pollution. When cars burn gasoline or diesel, they emit harmful pollutants, including carbon monoxide, nitrogen oxides, and hydrocarbons. These pollutants can cause respiratory problems, irritate the eyes, and even lead to more severe issues such as cancer and heart disease. Vehicle emissions are one of the main contributors to smog, which can make it difficult to see and breathe. In addition to the immediate health risks, car pollution also contributes to global warming and climate change by increasing carbon dioxide and other greenhouse gas emissions. While modern vehicles are becoming more fuel-efficient, the growing popularity of gas-guzzling SUVs and the increasing number of miles driven offset much of this progress.

Cars burning gasoline and diesel fuel

Gasoline engines, for instance, may not get enough air into the cylinder for complete combustion, leading to the release of carbon monoxide. While diesel engines have excess air, resulting in lower carbon monoxide emissions, they still produce measurable amounts. Additionally, the combustion process in diesel engines can transform nitrogen from the air into nitrogen oxides, which are reddish-brown gases that irritate the lungs and eyes.

The impact of these emissions on human health is significant. Carbon monoxide, for example, is a colorless and odorless gas that combines with blood, limiting its oxygen-carrying capacity. Nitrogen oxides irritate the respiratory system and can weaken defences against respiratory infections. Benzene and other toxic air pollutants found in vehicle emissions have been linked to adverse effects on nearly every organ system in the body and various types of cancer. Marginalised communities, including low-income households and communities of colour, often bear the brunt of this pollution due to their proximity to heavily trafficked areas.

To address these issues, steps have been taken to reduce emissions from gasoline and diesel vehicles. The Clean Air Act, first passed in 1970, mandates engines and fuels to produce fewer emissions. Catalytic converters were introduced in 1976 to reduce toxic air pollutants, leading to the phase-out of leaded gasoline by 1996. More recently, Ultra-Low-Sulfur Diesel (ULSD) fuel has been introduced, which helps reduce emissions in newer and older diesel engines. Additionally, advancements in electric vehicles (EVs) and hybrid technologies offer zero or reduced tailpipe emissions, providing a cleaner alternative to traditional gasoline and diesel vehicles.

Vehicle exhaust and tailpipe emissions

The exhaust from vehicles contains dangerous air pollutants, including nitrogen oxides (NOx), volatile organic compounds (VOCs), and particle pollution or soot. These pollutants can have adverse impacts on nearly every organ system in the body. Exposure to pollution is inequitable, with Latinos, Blacks, and lower-income households bearing a disproportionate burden. Studies have shown that Asian Americans, Black people, and Latino people experience higher concentrations of harmful particulate matter air pollution than the average person in the US.

The combustion of fuel in a vehicle's engine produces exhaust, which can contain criteria pollutants and greenhouse gases. Criteria pollutants, such as carbon monoxide, hydrocarbons, and nitrous oxide, contribute to global warming and poor air quality. Greenhouse gases, like methane, nitrous oxide, and carbon dioxide, are a major contributor to climate change. The burning of gasoline and diesel fuel creates harmful byproducts, including nitrogen dioxide, carbon monoxide, hydrocarbons, benzene, and formaldehyde.

To reduce vehicle exhaust and tailpipe emissions, individuals can choose more fuel-efficient vehicles, drive less, and maintain their vehicles to ensure they are running as efficiently as possible. Public transportation, carpooling, and electric vehicles are also options to reduce emissions. Additionally, observing posted speed limits and accelerating gradually can help reduce pollution, as driving faster and rapid acceleration burn more fuel and emit more pollutants.

Driving faster and accelerating quickly

Aggressive acceleration can result in significantly higher fuel consumption and emission rates. A study by researchers at Virginia Tech found that traffic-calming measures that reduce vehicle speeds may contribute to enhanced road safety but can also lead to increased fuel consumption and emissions. However, traffic circles were found to produce the least increase in vehicle fuel consumption and emissions, allowing smoother driving patterns with milder acceleration behaviour.

To improve air quality and reduce emissions, drivers should avoid sharp acceleration and practice gradual acceleration instead. This not only reduces emissions but also saves money. Driving smoothly is key to saving fuel. For example, in a 2002 EnergyWise rally in New Zealand, the winning driver achieved the best fuel efficiency by maintaining a smooth driving pattern.

Overall, driving faster and accelerating quickly contribute to air pollution by increasing fuel consumption and emissions. To reduce pollution, it is important to observe speed limits, accelerate gradually, and drive smoothly.

Inequitable exposure to pollution

Cars, trucks, and buses powered by fossil fuels are major contributors to air pollution. Transportation emits more than half of the nitrogen oxides in the air and is a significant source of heat-trapping emissions in the US. The exposure to pollution is inequitable, with the harms disproportionately affecting Latinos, Blacks, Asian Americans, and lower-income households.

Analysis of emissions from cars, SUVs, trucks, and buses reveals that Asian Americans are exposed to 34% higher PM2.5 concentrations than the average person in the US, while Black people experience concentrations 24% higher and Latino people 23% higher. In contrast, White people have an average exposure that is 14% lower than the national average. This disparity is even more pronounced in the Northeast and Mid-Atlantic regions, where Asian American, Black, and Latino residents are exposed to significantly higher levels of air pollution from vehicles than other demographic groups.

One factor contributing to this inequitable exposure is the proximity of marginalized communities to freight centres and heavily travelled roadways. Urban segregation in US cities has resulted in communities of colour and low-income neighbourhoods being located near these pollution sources, with limited access to resources to mitigate or escape the pollution. Additionally, individuals and households without personal vehicles tend to live in urban areas surrounded by vehicle traffic, leading to higher exposure to vehicle pollution.

The harmful health impacts of air pollution disproportionately affect these marginalized communities. Pollutants from vehicle exhaust have been linked to adverse effects on almost every organ system in the body, including lung and heart ailments, asthma, developmental problems in children, and an increased risk of cancer and premature death. Fine particles emitted by vehicles can penetrate deep into the lungs, causing serious health risks, especially for young children and individuals with asthma.

Carbon dioxide and other greenhouse gases

Carbon dioxide (CO2) is the most common human-caused greenhouse gas emitted by vehicles. The burning of fossil fuels like gasoline and diesel releases carbon dioxide into the atmosphere. The main sources of carbon dioxide emissions from vehicles are the burning of fuel and the vehicle's exhaust. The amount of carbon dioxide emitted depends on the vehicle's fuel, fuel economy, and the number of miles driven per year. A typical passenger vehicle emits about 4.6 metric tons of carbon dioxide annually.

In addition to carbon dioxide, vehicles emit other greenhouse gases such as methane (CH4) and nitrous oxide (N2O). These gases are produced by the combustion of gasoline and contribute to the build-up of greenhouse gases in the Earth's atmosphere, leading to climate change. The impact of these emissions is significant due to their high global warming potential. To address this issue, the EPA has developed standards and regulations for vehicle emissions, including the use of low-carbon fuels and improved vehicle technologies.

The transportation sector is a major contributor to greenhouse gas emissions, with road transport accounting for about a fifth of EU emissions and passenger cars responsible for 61% of total CO2 emissions from EU road transport. The EPA has implemented strategies such as SmartWay to improve supply chain efficiency and reduce greenhouse gas emissions in the freight transportation sector. Additionally, the EPA provides resources like the Green Vehicle Guide to help consumers choose more fuel-efficient and environmentally friendly vehicles.

It is important to note that electric vehicles (EVs) have a significantly lower environmental impact than conventional vehicles. While EVs do not emit tailpipe emissions, the electricity production process may still generate emissions. In areas with relatively low-polluting energy sources for electricity generation, EVs offer a substantial life cycle emissions advantage over conventional gasoline or diesel vehicles. However, in regions with higher-emissions electricity, the environmental benefits of EVs may be less pronounced.

To reduce carbon dioxide and other greenhouse gas emissions from vehicles, individuals can make conscious choices. These include driving less, car-sharing, and switching to more fuel-efficient or electric vehicles. Additionally, observing speed limits, accelerating gradually, and anticipating the road ahead can help reduce fuel consumption and lower emissions.

Frequently asked questions