Road Pollutants: How Far Do They Really Travel?

Road pollution is a serious issue, with more than 11 million people in the United States living within 500 feet of a major highway. This proximity to roads has been associated with decreased lung function in adults with asthma and an increased risk of health problems such as asthma, cancer, heart attacks, strokes, and pre-term births. The impact of road pollution extends far beyond the immediate vicinity of roads, with one study finding that roads have a zone of influence that covers more than 70% of the land area. In Great Britain, only 12% of land is more than 1 km from roads, and less than 4% of land is more than 2.5 km away. This means that the majority of the population is exposed to road pollution on a daily basis, with potential health consequences.

Air pollution from roads can travel up to 500 feet, where the highest rates of asthma, cancer, heart attacks, strokes, reduced lung function, pre-term births and other health problems are found

In California, air quality regulators warn against building within 500 feet of a freeway, and even up to 1,000 feet, due to the high levels of traffic pollution and associated health risks. Increasing the distance from a road to more than 500 feet might decrease concentrations of some air pollutants by at least 50%.

A study in Great Britain found that 25% of land was less than 79 meters from a road, 50% of land was less than 216 meters, and 75% of land was less than 527 meters. This means that roads have a significant zone of influence, with potentially less than 6% of land escaping any impact from road pollution.

When choosing a home, school, or daycare, it is essential to consider the proximity to major roads and freeways to minimise exposure to air pollution and associated health risks.

Living within 500 feet of a major road can increase the risk of asthma in adults

According to the CDC, more than 11 million people in the United States live within 500 feet of a major highway. The vehicle traffic on these roadways is a major source of noise and air pollutants, such as particulate matter, nitrogen oxides, carbon monoxide, and ozone, which are known health hazards.

A study by Balmes et al. in 2009 found that living near a major road was associated with decreased lung function in adults with asthma. Increasing the distance from the road to more than 500 feet might decrease concentrations of some air pollutants by at least 50%.

In Great Britain, a study found that 25% of land was less than 79 m from a road, 50% of land was less than 216 m and 75% of land was less than 527 m. This means that roadless areas are scarce, with only around 12% of land in Great Britain more than 1 km from roads and less than 4% of land more than 2.5 km from roads.

The impact of living near major roads on asthma risk has also been observed in children. A study by Perez et al. in 2012 estimated that 8% of childhood asthma cases in Los Angeles County, California, could be partly attributed to living close to a major road. Similarly, a study by McConnell found that children living within 75 meters (about 82 yards) of a major road had a nearly 50% greater risk of having had asthma symptoms in the previous year than children who lived more than 300 meters (about 328 yards) away.

In California, air quality regulators warn against building within 500 feet of a freeway

In 2005, California air quality officials delivered a warning to cities and counties to avoid putting new homes in high-pollution zones within 500 feet of freeways. This advice was based on years of research that showed the detrimental health effects of living near a freeway. However, in 2018, the air board shifted its stance, recommending anti-pollution features such as air filters, sound walls, and thick vegetation as promising strategies to reduce health risks.

Despite this shift in focus, it is still advisable to choose locations as far from the freeway as possible when selecting a home, school, or daycare. Air quality regulators suggest avoiding sites within 500 feet or even 1,000 feet of a freeway, as traffic pollution and associated health risks are generally highest within this range.

Living near a major road has also been associated with decreased lung function in adults with asthma. Increasing the distance from the road to more than 500 feet can decrease concentrations of some air pollutants by at least 50%. In Great Britain, a study found that 25% of the land was less than 79 meters from a road, and only about 12% of the land was more than 1 kilometre away. This highlights the ubiquity of road pollution and the importance of considering its impact when planning new developments.

In Great Britain, 25% of land is less than 79 metres from a road, 50% is less than 216 metres, and 75% is less than 527 metres

Road pollution is a serious issue, with pollutants such as particulate matter, nitrogen oxides, carbon monoxide, and ozone posing known health hazards. Living near a major road has been associated with decreased lung function in adults with asthma, and increased rates of asthma, cancer, heart attacks, strokes, and pre-term births. When choosing a home, school, or daycare, it is recommended to avoid locations within 500 feet of a freeway, where air quality regulators warn against building. Increasing the distance from a road to more than 150 metres (500 feet) can decrease concentrations of some air pollutants by at least 50%.

Only 12% of land in Great Britain is more than 1km from roads, and less than 4% is more than 2.5km away

Road pollutants can travel a long way from the road. In fact, in Great Britain, only 12% of land is more than 1km from roads, and less than 4% is more than 2.5km away. This means that roads have a zone of influence that extends across more than 70% of the land area, with potentially less than 6% of land escaping any impact.

The impact of road pollution on health is well-documented. Living near a major road has been associated with decreased lung function in adults with asthma, and increased rates of asthma, cancer, heart attacks, strokes, reduced lung function, pre-term births, and a growing list of other health problems. Air quality regulators in California warn against building within 500 feet of a freeway, or even 1,000 feet, as that is where traffic pollution is generally highest. Increasing the distance from the road to more than 150 metres, or approximately 500 feet, might decrease concentrations of some air pollutants by at least 50%.

In the US, more than 11 million people live within 150 metres of a major highway, exposing them to noise and air pollutants such as particulate matter, nitrogen oxides, carbon monoxide, and ozone, which are known health hazards.

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