Air pollution’s invisible toll on your health

1 Air pollution illustration
(Illustration: NYTimes)
President Joe Biden’s proposed infrastructure plan calling for huge investments in clean energy, public transportation and electric vehicles would do a lot more than slow the rate of devastating climate change. It would also protect the health of every American, especially young children and older adults, by reducing the harmful effects of invisible air pollutants inhaled year after year.اضافة اعلان

Toxic substances like fine particulate matter, nitrogen dioxide and ozone form primarily when fossil fuels are burned and enter the atmosphere in the exhaust from motor vehicles, heating units and smoke from wildfires. Inhaling such pollutants can cause bodily damage that lasts for years, if not for life, and may even lead to death.

Air pollution has long been recognized as a human health hazard, prompting the enactment of the Clean Air Act of 1963. Under the act, air quality standards are periodically revised by the Environmental Protection Agency. Though these standards are meant to be based on up-to-date research, they are subject to economic and political pressures, sometimes at the expense of public health.

Those most vulnerable to illness and premature death related to air pollution include children, pregnant women, the elderly and those with preexisting heart or lung disease. The risk is greatest among people who live in poor neighborhoods, many of which are close to major roads or near industrial sources of pollution.

Since 1990, implementation of the amended Clean Air Act has resulted in about a 50% decline in emissions of key air pollutants. Still, new research has shown that this decline is not nearly enough to protect the most vulnerable Americans from the damaging effects of air pollution. A 17-year study based on hospital records of more than 63 million older adults has shown that as recently as 2016, as a group they faced serious health risks from breathing levels of pollutants even at pollution levels that are below current national and international guidelines. For example, for each unit increase in long-term exposure to fine particulates in the air (measuring 2.5 micrometers in diameter and invisible to the naked eye), 2,536 people were hospitalized with strokes.

The report, published in the journal Circulation, found that years of breathing low concentrations of fine particulate matter, nitrogen dioxide and ozone “poses a significant risk to cardiovascular and respiratory health among the elderly population of the United States.” Translation: Older people are more likely to suffer a heart attack, stroke, atrial fibrillation and pneumonia because of air pollution, resulting in thousands of additional hospital admissions each year.

A team of 12 scientists, headed by Mahdieh Danesh Yazdi of Harvard School of Public Health, based this finding on an analysis of air pollution exposure and health outcomes among all fee-for-service Medicare beneficiaries ages 65 and older who were living in the United States between 2000 and 2016.

“Each unit increase in levels of particulate matter, nitrogen dioxide and ozone were associated with thousands of additional admissions” to hospitals each year, the team reported. Yazdi, a professor and research fellow in environmental health, said in an interview that “hundreds of thousands of lives could be saved” by improving the quality of the air that Americans breathe.

With half the population of the United States routinely exposed to levels of common pollutants shown to be hazardous in the study, the researchers concluded that “this issue should be of great concern to clinicians and policymakers alike.”

By making the data on air quality and health outcomes publicly available, Yazdi said, the team hoped to give people “some power” to improve air quality and better protect public health.

“Both clinicians and patients can be advocates and apply pressure on public officials to control the sources of pollution and improve the air we all breathe,” she said. “Even if air pollution can’t be fully mitigated, we should strive to do better. Levels of pollutants now considered safe can still have harmful effects and result in bad outcomes.”

The team also suggested that people pay attention to the air quality where they live and do their best “to avoid harmful exposure over long periods of time.” There was a dramatic example of such avoidance last summer when wildfires burned across the state of California, forcing many people to remain indoors with windows and doors shut to minimize breathing smoke-related pollutants.

According to the EPA, “Larger and more intense wildfires are creating the potential for greater smoke production and chronic exposures in the United States, particularly in the West.”

But while such extreme short-lived instances of severe air pollution are readily identified, so-called background levels remain unnoticed and unmonitored by the general public, leaving millions of people susceptible to the insidious damage they can cause. You can get a reasonable estimate of these levels by checking the Air Quality Index where you live each day, and avoiding prolonged or heavy exertion outdoors on days when air quality is poor.

Worldwide, an international research team reported last year, air pollution “accounts for about 9 million deaths per year,” they wrote in Frontiers in Public Health. “The health of susceptible and sensitive individuals can be impacted even on low pollution days.”

Particulate matter contains tiny liquid or solid droplets that are easily inhaled. In addition to damaging the lungs, these microscopic particles can enter the bloodstream and have damaging effects elsewhere in the body, including the brain.

People over 75 in the new study were more likely to be hospitalized than those closer to 65, and whites faced a greater risk of admission than Black individuals from exposure to particulate matter. But exposure to nitrogen dioxide, also a product of burning fossil fuels, was shown to be more harmful to Blacks than to whites.

Furthermore, for the study population overall, the greatest risk of hospital admissions occurred at lower concentrations of air pollutants, the team reported.

Other studies have shown that even short-term exposure to low levels of pollutants can be hazardous to people with conditions like chronic obstructive pulmonary disease and asthma. Exposure to air pollution early in life can result in respiratory, cardiovascular, mental and perinatal disorders, according to the United States Global Change Research Program.

Air pollution can also have indirect health effects because of its close link to climate change. Pollutants increase the amount of sunlight that reaches the Earth, warming it, and warmer climates increase the spread and intensity of infectious diseases that can result in epidemics.

Given that most of the pollutants we inhale enter the atmosphere from sources like industrial machinery, power plants, combustion engines and cars, efforts to switch from fossil fuels to clean energy sources like wind power and powering vehicles with electric energy instead of gasoline and diesel can have a major impact on air quality.

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