Healthy AgingVitamin Mineral Research

Air Pollution: How Harmful Is It?

When breathing is a health risk, what can be done?

Take a deep breath in. Slowly exhale.

Deep, conscious breathing can be restorative, balancing, and calming. The experience is even better in nature – a forest with trees towering overhead, or by the ocean with the sand between our toes. We take it for granted that the very act of breathing is a health-promoting activity, and how can it not be? No adult or child can hold their breath much beyond a minute without the need for a refreshing blast of oxygen.

Studies of meditation and controlled breathing techniques reveal the beneficial effects of deep breathing.[1],[2] We also can thank science for showing us that the experience of breathing in a natural setting is more restorative than in an urban environment.[3],[4]

But what if you were told this very experience of breathing may have a negative impact on your health? Some of us may accept this fact as reasonable, be it from personal experience living in or traveling to a region with increased traffic and industry, or from experiencing asthma or chronic obstructive pulmonary disease (COPD), both conditions that make air quality more noticeable. Whether we do or do not want to accept it, the data show that air quality significantly impacts our health.[5],[6]

A variety of air pollutants affect our health

The particulate matter (PM) found in air has variable effects depending on particle size. There are two main thresholds used to assess air quality: 2.5 micrometers (referred to as PM2.5) and 10 micrometers (referred to as PM10). Although both sizes can negatively affect our health, it is the smaller particles that are more harmful as they can be inhaled into the lungs more deeply.[7],[8]

An estimated 3.3 million premature deaths occur worldwide each year due to outdoor air pollution, mostly associated with PM2.5 exposure.

An estimated 3.3 million premature deaths occur worldwide each year due to outdoor air pollution, mostly associated with PM2.5 exposure. This includes polluting emissions from residential energy use, traffic and power generation, and agriculture, with the amount of dangerous components including PM2.5 levels varying by region. And the changing climate and increasing temperatures are making things worse, resulting in approximately 290 additional air pollution-related deaths per year in the US alone between 1994 and 2012.[9]

In addition to PM, common air pollutants include carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs), ozone (O3), and heavy metals. Many studies look at the impact of individual pollutants or PM on health, but it is the combined effects of these elements that can lead to chronic respiratory and heart disease, lung cancer, acute respiratory infections, chronic bronchitis, stroke, asthmatic attacks, and premature mortality.[10],[11]

Polluted air also contains even smaller “ultrafine” particulates in the 100 nanometer size range (PM0.1).[12] Both PM2.5 and PM0.1 impact health in part by causing oxidative stress and inflammation,[13] leading to activation of signalling pathways that alter gene expression.[14] Additionally, the ultrafine PM0.1 particles are capable of passing from the respiratory system into the bloodstream, from which they can travel throughout the body with potential effects on coagulation and nervous system function.[9] These ultrafine particles have been shown to localize in mitochondria, the energy-producing organelles within cells, inducing major structural damage. PM0.1 particles have been shown to deplete levels of glutathione, an important antioxidant, within cells.[15]

Additionally, the ultrafine PM0.1 particles are capable of passing from the respiratory system into the bloodstream, from which they can travel throughout the body with potential effects on coagulation and nervous system function.

The very young and the elderly are most susceptible to the negative impacts of air pollution. In the very young this susceptibility may be a due to the inhalation of a higher volume of air per body weight than in adults, combined with an immature immune system.[16] In the elderly, a reduced capacity to respond to exposures contributes to the damage.[17]

What can be done to reduce exposure?

A variety of websites provide air quality data in real time. One that shows the air quality in major cities and regions of North America and other countries can be found here. A city of interest can be searched, and the current level as well as data from the past 48 hours is displayed including particle size, air pollutant levels, temperature, humidity, and wind patterns. These data can help one plan exercise and outdoor activities for times when pollution levels are lower. (Exercise actually has been shown to increase the blood-clotting effect of air pollutant exposure.[18])

Second, finding a region with trees can reduce the exposure to these toxins.[19] Trees remove air pollution by the interception of particulate matter on plant surfaces and the absorption of gaseous pollutants through the leaves. It is known that trees also positively impact air pollutant levels by reducing air temperature, reducing wind speeds, and locally leading to less need for cooling, thereby reducing emissions from surrounding buildings.

A possible remedy for some – particularly those with conditions significantly affected by air pollution, such as asthma or COPD – is to wear a mask in regions with poor air quality. There are different mask designs and qualities, and looking for one that is effective for reduction of exposure to known pollutants as well as one that is functional for exercise may be helpful for cyclists and runners exercising in high-pollution areas.

What can be done to reduce damage?

Antioxidants or antioxidant-promoting strategies may help combat the negative health effects of air pollutants. Nuclear factor erythroid 2-related factor (Nrf2) is a key transcription factor that may help protect against oxidative stresses induced by air pollution.[20] Ginkgo biloba has been shown to induce phase II detoxification enzymes via Nrf2 involved pathways, as have green tea polyphenols, sulforaphane, milk thistle, and pomegranate. [21],[22] N-acetylcysteine has been shown to reduce air pollutant-induced increased airway responsiveness in individuals with airway hyper-reactivity, reducing the need bronchodilators.[23] And of course, because intracellular glutathione is depleted with exposure to air pollution, direct strategies for increasing cellular glutathione levels may be of value.

A combination of B-vitamins (2.5 mg/d folic acid, 50 mg/d vitamin B6, and 1 mg/d vitamin B12) was shown to regulate heart rate and white blood cell counts in those exposed to air pollution.

Some supplement combinations have been studied in individuals exposed to air pollution. A combination of B-vitamins (2.5 mg/d folic acid, 50 mg/d vitamin B6, and 1 mg/d vitamin B12) was shown to regulate heart rate and white blood cell counts in those exposed to air pollution.[24] The same B-vitamin combination was shown to ameliorate PM2.5-associated reductions in mitochondrial DNA content, and to prevent genetic changes related to mitochondrial oxidative energy metabolism.[25] In addition, a multivitamin combination was shown to improve immune function and health conditions that are worsened by exposure to air pollutants.[26]

Summary

It is important to consider strategies to minimize air pollution exposure and reduce cellular damage. Air quality monitoring data can help one to plan outdoor activities for times of lower pollution, while filter masks can reduce exposure to particulates. Certain supplements also may help reduce the impact of exposure on an ongoing basis.  Specifically, support may be found with the use of supplements containing Nrf2-upregulating substances, N-acetylcysteine, glutathione, certain B-complex vitamins, and multivitamins.

 

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