Freeway Pollution: How Dangerous Is The Air?

Air pollution near freeways is a pressing issue, with studies showing that pollutants like NO2, volatile organic compounds, carbon monoxide, ultrafine particles, and more, are prevalent near busy roads. These pollutants have been linked to various health issues, including respiratory problems, cardiovascular disease, reproductive issues, and even cancer. The impact is more severe in poorer urban neighborhoods, affecting people of color, those uninsured, and those experiencing linguistic isolation. While strategies like improved indoor ventilation, tightened fuel and emission standards, and the use of obstacles to block pollution are being considered, the challenge of reducing pollution in existing homes near freeways remains.

Health risks: cancer, asthma, heart disease, pre-term births, etc

Air pollution from freeways can have serious health impacts, both immediate and long-term. The pollution is caused by a variety of factors, including tailpipe emissions, dust from brake pads and tyres, and diesel soot. These pollutants can contain harmful gases and particles such as nitrogen dioxide, carbon monoxide, particulate matter, and volatile organic compounds (VOCs).

Living near freeways has been linked to various health risks, including cancer, asthma, heart disease, and pre-term births. Studies have found that people living within 500 feet of freeways suffer from higher rates of asthma, heart attacks, strokes, reduced lung function, and cancer. The risk of cancer is especially high near roads frequented by diesel trucks, which emit carcinogen-laden soot that can deposit deep in the lungs. Ultrafine particles from vehicle exhaust can also pass through the lungs and enter the bloodstream, potentially harming the heart, brain, and other organs.

Pregnant individuals are also at risk, as exposure to air pollution has been associated with premature births, low birth weight, and stillbirths. Children are particularly vulnerable to the effects of air pollution, with increased risks of developing asthma, bronchitis, and other respiratory illnesses. Exposure to air pollution during childhood may also lead to cognitive and emotional problems later in life, including an increased risk of cerebral palsy.

Overall, air pollution from freeways poses a significant risk to public health, with potential impacts on a range of organs and systems in the body. It is important for individuals to take steps to limit their exposure to freeway pollution, such as choosing locations farther from freeways when possible and reducing time spent outdoors near busy highways.

Pollutants: NO2, volatile organic compounds, carbon monoxide, etc

Air pollution near freeways is a serious issue, with people living, working, or travelling within close proximity to these roads being exposed to high levels of dangerous pollutants. These pollutants include NO2, volatile organic compounds, carbon monoxide, and more, which can have detrimental effects on human health.

NO2, or nitrogen dioxide, is a highly reactive gas that can irritate the respiratory system and exacerbate respiratory conditions such as asthma. Studies have shown that concentrations of NO2 decrease with distance from roadways, with levels dropping to background concentrations within 100-150 meters of a road. However, in areas with greater traffic volumes, NO2 levels can remain elevated even beyond this distance.

Volatile organic compounds (VOCs) are another concern near freeways. VOCs are emitted from vehicles but also from common household products like paints, varnishes, cleaning agents, and even fuels. These compounds can have a range of health effects, from mild irritation to more severe impacts, depending on the specific compound and the level and duration of exposure. While filters can help reduce indoor VOC levels, proper ventilation during and after using products that emit VOCs is crucial.

Carbon monoxide is a toxic gas produced by incomplete combustion, often from vehicle engines. Similar to NO2, carbon monoxide concentrations exhibit a decay with distance from roadways. However, due to its toxicity, even small increases in ambient carbon monoxide levels near freeways can pose health risks to nearby residents.

Other pollutants of concern near freeways include ultrafine particles, black carbon, and metals associated with brake and tyre wear. These pollutants can have a range of health impacts, including neurological changes, pulmonary inflammation, and cardiovascular problems, and increased mortality rates.

Protecting oneself from freeway pollution is challenging but not impossible. Strategies include using high-efficiency air filters, keeping doors and windows closed, living farther from freeways, and advocating for better urban planning and emission reduction policies.

Vehicles: car, truck, light-duty, heavy-duty, etc

Cars, trucks, and other vehicles are a major source of pollution near freeways. The pollution from vehicles is not limited to the immediate vicinity of the freeway but can spread to surrounding neighbourhoods, increasing residents' risk of cancer, asthma, heart disease, and other illnesses.

Most passenger cars and trucks are classified as light-duty vehicles. Light-duty vehicles are subject to different regulations and standards than heavy-duty vehicles. For example, the US Environmental Protection Agency (EPA) has implemented light-duty GHG regulations for passenger vehicles and trucks, which aim to cut greenhouse gas (GHG) emissions and nearly double fuel efficiency. Light-duty vehicles can also participate in EPA's SmartWay light-duty program, which identifies top-performing vehicles in terms of fuel economy and emissions to assist consumers in making environmentally friendly purchases.

Medium- and heavy-duty vehicles, on the other hand, are those weighing more than 10,000 pounds. This includes delivery trucks, tractor-trailers, buses, garbage trucks, and cement mixers. While they make up just 10% of vehicles on the road, they generate more than 25% of the total global warming emissions from the transportation sector. Heavy-duty vehicles emit a range of pollutants, including nitrogen oxides (NOx), volatile organic compounds, particulate matter, and greenhouse gases such as carbon dioxide and methane. These emissions are strongly related to a vehicle's weight, with tire wear and brake use in heavy-duty trucks posing a particular issue for communities alongside freeways.

The pollution from heavy-duty vehicles has disproportionate health impacts on certain communities. Historically, Black, Indigenous, and People of Color (BIPOC) communities, as well as low-income and socioeconomically disadvantaged neighbourhoods, have borne the brunt of emissions from these vehicles. These communities are exposed to higher rates and increased exposure to pollutants, leading to negative health outcomes such as increased asthma rates, heart and lung disease, and certain types of cancer.

To reduce pollution from vehicles near freeways, several strategies can be implemented. Transitioning from diesel fleets to electric or alternative fuel vehicles can significantly reduce toxic tailpipe emissions. Additionally, living farther from freeways and major intersections can help reduce exposure to pollution, as can installing high-efficiency air filters in homes.

Strategies: air filters, ventilation, blocking pollution, etc

Air pollution near freeways is a serious issue, with millions of Americans exposed to harmful pollutants every day. Living near a freeway can increase the risk of cancer, asthma, heart disease, and other illnesses. The pollution from vehicles can spread to surrounding neighbourhoods, and even beyond 500 feet, which California air quality regulators deem unhealthy. With that in mind, here are some strategies to mitigate the impact of freeway pollution:

Air Filters

High-efficiency air filters can be installed in central heating, ventilation, or air conditioning systems to block tiny pollution particles. These filters should be rated 13 or higher on the 16-point MERV (Minimum Efficiency Reporting Value) scale. However, it's important to note that filters may not remove all harmful pollutants, especially toxic gases like benzene and 1,3-butadiene, which require more costly charcoal filters. Additionally, filters are more effective in newer, well-sealed homes than in older dwellings.

Ventilation

If you live near a freeway, keeping doors and windows closed can help reduce the amount of pollution entering your home. Using air conditioning or standalone air-cleaning devices can also lower particle pollution levels, but they are most effective in a single room and require constant operation.

Blocking Pollution

Living behind a sound wall or a vertical separation, such as an elevated or depressed freeway, can help disperse pollutants. Vegetation barriers, such as trees and bushes, can also be effective in reducing downwind pollution concentrations by altering airflow and intercepting pollution. Combining vegetation with noise barriers has been shown to be more effective than either method alone. Additionally, living in areas with buildings of varying heights, parks, and open spaces can help disperse pollutants away from your location.

Other Strategies

Infill development, the opposite of urban sprawl, can reduce the need for long commutes, thereby decreasing vehicle emissions and improving public health. Additionally, local and state governments can implement strategies from resources like the California Air Resources Board's "Land Use Handbook," which provides recommendations for siting schools, daycares, playgrounds, and housing at safe distances from freeways and high-traffic roads.

Demographics: poorer, urban, people of colour, uninsured, etc

Poorer, urban communities of colour are disproportionately affected by pollution near freeways. More than 49 million Americans live within a mile of a highway, facing significant health risks from traffic pollution. This includes higher rates of asthma, cancer, heart disease, and other illnesses. In Chicago, for example, the top five neighbourhoods for cancer risk and respiratory problems are all within a mile of major thoroughfares, and 53.8% of the residents are non-white. Similarly, in New Orleans, the Claiborne Avenue Alliance has been advocating for the removal of the elevated expressway, citing the negative effects of the I-10 freeway on adjacent neighbourhoods, including severe pollution and increased health risks for residents.

In addition to the physical health impacts, freeway pollution also affects vulnerable communities financially. The cost of implementing measures to mitigate the effects of pollution, such as installing high-efficiency air filters or stand-alone air-cleaning devices, can be a financial burden for low-income households. Moreover, freeway pollution disproportionately affects uninsured individuals, as they may have limited access to healthcare services to treat pollution-related health issues.

The impact of freeway pollution on poorer, urban communities is further exacerbated by the design of the highways themselves. At-grade freeways, where lanes are at the same level as surrounding buildings, put vehicle tailpipes closer to people's lungs, increasing exposure to pollutants. Additionally, "street canyons" formed by blocks of tall buildings can trap pollution, preventing its dispersal and concentrating it in these areas.

The issue of freeway pollution and its impact on vulnerable communities is not limited to a single city or region. Across the United States, nearly 11,000 census tract neighbourhoods are within a mile of an interstate highway or major freeway, and these communities face higher rates of chronic diseases, such as asthma, above the national averages. The constant commuter traffic on these highways contributes to toxic air pollution, affecting the health and well-being of the residents in these neighbourhoods.

While there have been efforts to address this issue, such as the "Highways to Boulevards" movement, which aims to replace ageing highways with city streets, housing, and green spaces, the cost of repairing or replacing freeways is often a barrier. Additionally, critics argue that removing highways may not guarantee new development or improved health outcomes for nearby neighbourhoods. Nonetheless, the disproportionate impact of freeway pollution on poorer, urban communities of colour remains a pressing issue that requires further attention and sustainable solutions.

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