Ten guidelines for a healthy life: Korean Medical Association statement (2017).
December 15, 2017 148 p (in English)

doi: https://doi.org/10.26604/979-11-5590-078-9-93510-9

09Paying Attention to Particulate Matter (PM10 and PM2.5) and Emerging Infectious Diseases

09Paying Attention to Particulate Matter (PM10 and PM2.5) and Emerging Infectious Diseases

Preventing damage from particulate matter and emerging infectious diseases paves the road to longevity!

Summary

◆ Background

In 2016, the Organization for Economic Co-operation and Development (OECD) identified the Republic of Korea as the country in which mortality due to air pollution was expected to increase most rapidly by 2060. Due to air pollution, 1% of the gross world product (GWP) is expected to be lost in 2060, by means of increased medical expenses and reduced labor productivity; South Korea has a projected loss of gross domestic product (GDP) of 0.63%, which is the highest projected loss among the OECD nations. Meanwhile, the epidemics of Middle Eastern respiratory syndrome (MERS) in Korea and the Zika virus in Central and South America have heightened public interest in emerging infectious diseases, which calls for practical preventive guidelines.

◆ Purpose

To make Korea safe by preventing health damage from particulate matter and fostering public interest in emerging infectious diseases.

◆ Contents

1. Refrain from going out and using cars when a particulate matter watch or warning is declared

The major source of particulate matter (PM) in Korea is traffic, which must be curtailed to reduce the levels of PM. Among the various types of exhaust emissions produced by vehicles, diesel engine exhaust (DEE) is the most important, and the influence of DEE on health has been researched the most. DEE contains many carcinogens, mutagens, and reproductive toxins.

2. Swine flu? MERS? Learning about emerging infectious diseases is important

Emerging or re-emerging infectious diseases are occurring everywhere. Studying and preparing before a trip can ensure safe travel.

3. Adhering to prevention practices for infectious diseases is the number-one component of health etiquette!

Practicing good hand hygiene and cough etiquette can help make Korea safe.

◆ Expected impact

These practical guidelines will greatly reduce the negative health effects of PM, because they will encourage people to avoid going out or using cars when a PM watch or warning is declared, resulting in the reduction of exposure and traffic exhaust. The suggestions made in this chapter will also help make Korea safe from emerging infectious diseases.

Keywords: PM2.5, Mortality, Health expenditure, Emerging infectious, Re-emerging infectious diseases, Hand hygiene

Best practices to follow

1. Refrain from going out and using cars when a particulate matter watch or warning is declared

2. Swine flu? MERS? Learning about emerging infectious diseases is important

3. Adhering to prevention practices for infectious diseases is the number-one component of health etiquette!

Fact Sheet ➊

Refrain from going out and using cars when a particulate matter watch or warning is declared

1.1 Health effects of particulate matter

Particles that are visible to the human eye are 100 μm in diameter or larger, whereas particulate matter (PM10) refers to small particles that are 10 μm or less in diameter. Fine particles (PM2.5) are extremely small, smaller than or equal to 2.5 μm in diameter. While large particles that are 10 μm in diameter or larger (e.g., cement powder or pollen) are naturally filtered out by the nose or bronchus, PM10 (e.g., cigarette smoke or automobile exhaust) is composed of respirable particles that can enter the respiratory tract and be deposited in the lung. The small size of these particles makes it easier for them to be deposited in the alveoli; the smaller the size, the more likely it is that the filtering function of the nasal mucous membrane will fail, resulting in the deposition of the particle in the alveoli. It is not yet clear how such forms of PM adversely affect the human body; the medical community predicts only that fine particles deposited in the alveoli will flow into the blood through the pulmonary capillaries, increasing the viscosity of the blood and elevating the risk of angina pectoris and myocardial infarction. These forms of PM also contain heavy metals such as lead, copper, chrome, zinc, and cadmium, and they also sometimes contain harmful acidic substances such as sulfate and nitrate. The PM floating in the air can absorb volatile organic chemicals (e.g., benzene and formaldehyde) emitted from construction materials or furniture, and can also absorb carcinogens such as polycyclic aromatic hydrocarbons (PAHs), which can turn into secondary toxic substances in the lung, thereby turning polluted indoor air into a serious threat to health. In other words, the harmful substances contained in PM are just as dangerous as the effects of the PM itself.

It has not been long since humanity discovered that people can die from the air pollution caused by PM and that PM can cause various diseases. In the winter of 1952 in London, the aggravation of sulfurous acid gas and PM pollution caused the Great Smog. When the smog became severe between December 5 and 12, the number of people hospitalized increased drastically, and the mortality rate was 3 times higher than usual, bringing the total death toll to 4,000. This incident led people to recognize that air pollution can cause serious harm to people.

Not many cases of exposure to high concentrations of air pollutants such as the Great Smog of London have been reported since then. However, we face continuous exposure to low-density air pollution, which is associated with a wide range of deleterious effects on health.

In both Korean and international air-born pollution epidemiologic studies, prospective cohort studies on the relationship between the mortality rate and chronic exposure to outdoor air pollution are very useful for elucidating the health effects of long-term exposure to dust. Using this method, researchers can follow up on a particular population group with specific characteristics over the course of years, and can evaluate mortality and morbidity within the group. In such cohort studies, confounding variables on the individual level (e.g., smoking history, occupation, etc.) can be controlled for, which means that the health effects of long-term exposure can be clearly identified. Representative cohort studies include a Harvard study on 6 U.S. cities [1], and a study by the American Cancer Society (ACS) [2].

The Harvard study on 6 U.S. cities reported that a 10 μg/m3 increase of PM2.5 led to a 14% increase in the mortality rate, and a 19% increase in the mortality rate from cardiovascular or respiratory diseases. The ACS study similarly showed that a 10 μg/m3 increase of PM2.5 led to a 7% increase in the total mortality rate, and a 12% increase in the mortality rate from cardiovascular or respiratory diseases. Taken together, these studies indicated that current concentrations of PM can seriously affect the health of citizens.

An increasing number of epidemiologic studies have confirmed the associations of short-term and long-term atmospheric exposure to PM2.5 with harmful health effects. Days, months, or years of long-term exposure to PM are statistically significantly associated with serious health effects (e.g., mortality rate, hospitalization, and outpatient visits). Chronic exposure to PM for years or decades seems to be even more closely associated with shortened lifespans, to a degree that cannot be explained by the simple accumulation of the acute effects of short-term exposure. Uncertainly remains regarding the magnitude of chronic health effects of long-term exposure to PM and the mechanisms underlying the effects of long-term and short-term exposure. According to the life table calculated by Brunekeef, relatively small differences in long-term exposure to atmospheric PM had a substantial impact on the lifespan [3]. For example, the calculations of the lifespan for American white males from 1969 to 1971 showed that chronic exposure to 10 μg/ m3 of PM reduced the life expectancy of the total population at 25 by 1.3 years. Additionally, if new evidence regarding the associations between exposure to PM and infant mortality, and its effects on intrauterine growth retardation and low birth-weight infants, is confirmed, continued long-term exposure will reduce the lifespan of the total population even more than Brunekeef predicted.

Recent toxicological studies have presented limited but intriguing evidence suggesting that specific mixtures of atmospheric PM or PM of a particular substance can have distinct effects on human health. Studies have suggested that certain kinds of PM can be more harmful than others; for example, an epidemiological study conducted in Utah Valley reported that exposure to PM10 particles laden with metal components when the steel mills were running was associated more strongly with harmful health effects than reduced exposure to PM10 particles when the steel mills were not running.

The sources of PM differ depending on their size. While PM2.5 is generated by the condensation of gaseous matter, PM10 contains other elements as well, such as coarse particles (PM10-2.5) that are created by mechanical pulverization. Therefore, the source of PM2.5 is more easily traceable than that of PM10, and the source of PM2.5 is also more relevant to understanding its health effects.

PM has also been reported to cause a reduction in heart rate variability, which is an indicator of elevated risk for serious cardiovascular problems, such as heart attack. Other studies have found that changes in hematologic features such as C-reactive protein, which is associated with an increased risk of ischemic heart disease, are associated with atmospheric PM exposure.

According to the research conducted by the National Cancer Institute in the U.S., which the World Health Organization (WHO) used as a major basis for classifying DEE as a group 1 carcinogen, the main carcinogenic factor in the emission is respirable elemental carbon [4]. In 2013, WHO took a step further and designated outdoor air pollution itself as a group 1 carcinogen, on the basis of sufficient evidence to conclude that it can cause cancer in humans [5].

In South Korea, there were 23,177 cases of lung cancer in 2013. Recently, among lung cancer patients, the number of lung adenocarcinoma patients with no history of smoking is increasing. According to the risk assessment method of the WHO, the mortality rate of lung cancer due to fine dust was as high as 21% when fine dust concentrations were calculated based on the current pollution level (PM2.5 concentration of 29 μg/m3). When calculated based on recent air pollution concentrations and air pollution concentration estimates, premature deaths in the Seoul metropolitan area amounted to 15,700, according to the annual average concentration of air pollution in the Seoul metropolitan area compared to the WHO baseline from 2010. If no countermeasures are taken, this number will jump to 26,388 in 2024. However, if countermeasures are taken, this figure is expected to be 35% less, at 17,143 (using a PM2.5 concentration of 20 μg/m3) [6]. As has been made evident by now, the impact of PM on our health cannot be underestimated.

According to the rates of disease-specific mortality caused by indoor and outdoor fine particulate air pollution estimated by the WHO in 2012, the total number of premature deaths was 7 million, which is more than the number of premature deaths caused by tobacco (Fig. 9.1). Integrating the global health damage caused by fine particles, the number of premature deaths was highest for angina (36%), followed by stroke (33%), chronic obstructive pulmonary disease (17%), acute lower respiratory disease (8%), and lung cancer (6%). The situation was no different in Korea: angina, stroke, chronic obstructive pulmonary disease, acute lower respiratory disease, and lung cancer were the predominant causes of death caused by fine particulate air pollution in Korea [7]. According to a study conducted in Korea, 15.9% of premature deaths in the Seoul metropolitan area in 2010 were caused by one of these diseases; that is, 1 out of 6 deaths was from fine particulate pollution.

Figure 9.1

Estimates of disease-specific mortality caused by indoor and outdoor air pollution (Adapted from WHO [7])

979-11-5590-078-9-93510-ch9f1.tif

The OECD warned of the seriousness of PM in Korea. Korea’s average PM2.5 concentration is 29 μg/m3, which is twice the OECD average.

At this rate, in 2060, Korea will be the OECD nation with the highest mortality rate and the largest economic loss due to air pollution. In its report, “The economic consequences of outdoor air pollution” (2016), the OECD identified Korea as the country in which mortality due to air pollution is expected to increase the most dramatically through 2060, estimating that premature deaths in Korea will account for 1,109 of every 1 million people (the highest rate among the OECD countries) [8]. The mortality rate of Korea in 2010 was similar to, or lower than, that of Japan and European Union countries, but it is projected to increase by more than 3 times by 2060, and this is expected to happen in Korea only. The same OECD report also anticipates severe economic losses for Korea. One percent of the annual GWP in 2060 is expected to be lost due to the increase of medical expenses and the decrease of labor productivity associated with air pollution; although Korea will suffer less air pollution damage than China or India, Korea’s loss of GDP is expected to be 0.63%, which is the highest among the OECD nations (Fig. 9.2).

Figure 9.2

GDP decrease due to air pollution (Adapted from OECD [8])

979-11-5590-078-9-93510-ch9f2.tif

Our society is now rapidly becoming an aging society, which means that the increase of fine particles can pose a serious threat to the health of vulnerable groups such as children and senior citizens. European OECD nations are trying to ban diesel cars from the market to improve air quality; similarly, it is time for Korea to implement wide-ranging and effective policies as well.

1.2 Particulate matter emissions from automobiles and their effects on health

There are various categories of transportation-induced exhaust emissions; diesel engine exhaust (DEE) is the most important, and the influence of DEE on health has been researched the most. DEE is composed of hundreds of gases and PMs; its gaseous components include carbon dioxide, oxygen, nitrogen, water vapor, carbon monoxide, nitrogenous compounds, sulfur compounds, and various kinds of low-molecularweight hydrocarbons (e.g., aldehydes [such as formaldehyde, acetaldehyde, and acrolein], benzene, 1,3-butadiene, PAHs, and nitro- PAHs). Diesel exhaust particulate (DEP) is the main contributing factor to the PM present in urban areas, and it consists of carbon core, absorbed organic compounds, small amounts of sulfates, nitrates, and heavy metals, and other infinitesimal elements. DEP is composed of PM2.5, and it also contains a fair amount of ultrafine particles with a size of 0.1 μm or less. These ultrafine particles function as a medium for absorbing organic substances due to their large surface area. Since they are very small, they can easily be inhaled, penetrating deep into the lungs and resulting in local or systemic health effects. In particular, their associations with respiratory and allergic diseases have been confirmed by a series of experimental studies [9].

Meanwhile, the fine particles emitted by cars coagulate and condense within seconds after emission, and the composition and distribution of these PMs significantly change as the distance from the main street increases. Therefore, people residing adjacent to main streets are likely to be exposed to more car-emitted particles, as well as to more toxic exhaust aerosol. Considering the mechanisms through which exposure to car exhaust emissions, including DEP, leads to inflammatory responses of the respiratory tract or the mucous membranes, changes in the immune response, or to increased sensitization to allergens, residing near main streets could result in high-density exposure to car exhaust emissions, with severe impacts on the residents’ health, potentially including the incidence of diseases such as asthma.

When inflammation is induced by traffic pollutants, the permeability of epithelial cells increases and the pollutants pass through the mucosal barrier, boosting allergen-induced inflammatory responses. Studies of human exposure have confirmed that exposure to DEP, NO2, and SO2 aggravated the symptoms of allergy patients and even induced direct inflammatory responses. In a panel study of 19 asthmatic children in Seattle, when the daily density of PM2.5 increased by 10 μg/m3, nitric oxide (NO) also increased by 4.3 ppb. As the exposure to atmospheric elemental carbon is increased, NO increases, which explains why car exhaust emissions can cause airway inflammation.

Additionally, it has been confirmed that DEP is associated with allergen sensitization and the incidence of allergic diseases. DEP is a form of respiratory PM that has a large surface area per unit mass, meaning that it easily absorbs protein components and acts as a medium for transferring them to the peripheral airways. Since it can bind with pollen allergens, it can function similarly to airborne antigens, or it could function as a stronger allergen. In vivo animal experiments have shown that exposure to DEP with allergens increased levels of the Th-2 cytokine and immunoglobulin E (lgE) more than exposure to allergens alone; it also increased inflammatory responses from target organ tissues [10]. In vitro culture studies have also shown that DEP-induced lgE production.

Oxidative stress is an important underlying mechanism of the toxic reaction through which traffic-induced air pollutants—that is, automobile exhaust—causes or aggravates asthma. In addition, childhood asthma is associated with a reduction of the number of components related to antioxidant defense mechanisms. Traffic-induced pollutants, such as NO2 and PM, generate free radicals and reactive oxygen species (ROS), and the ROS are counteracted in the airway by antioxidants. However, when these antioxidant defense mechanisms are overpowered, oxidative stress increases, and the subsequent inflammatory response causes an increase in the formation of ROS and inflammation. In other words, high-density ROS causes a depletion of local antioxidants, thereby precipitating the expansion of inflammatory responses outside of the target tissue, resulting in airway inflammatory responses such as those that occur in asthma [11].

Fact Sheet ➋

Swine flu? MERS? Learning about emerging infectious diseases is important

2.1 Pay attention to information on emerging infectious diseases

The Ebola outbreak in West Africa in 2014-2015 and the MERS epidemic in Korea in 2015 confirmed that infectious diseases in one region can spread to any other country, and that Korea is no exception; thus, interest in emerging infectious diseases has increased. The map in Figure 9.3 indicates that new infectious diseases may appear and some nearly eradicated diseases may reappear; therefore, we must pay attention to news about infectious diseases from health authorities. In particular, it is advisable to avoid visiting regions where emerging or reemerging infectious diseases are known to be present or to visit such regions after obtaining and carefully considering information about preventive measures.

Figure 9.3

Global distribution of emerging or re-emerging infectious diseases

(Modified from Heymann D [12])

979-11-5590-078-9-93510-ch9f3.tif

2.2 Safe overseas travel requires at least one month of pre-trip preparation

When planning overseas travel, it is necessary to plan to travel safely based on a global map of infectious diseases. If possible, refrain from visiting regions where emerging infectious diseases are known to be present; if you must travel to such areas, consult with medical specialists about appropriate preventive measures.

Depending on the situation in each region, vaccination can be helpful, but the normal immune response to vaccines takes about 2-4 weeks to take effect. Therefore, if you are planning to travel overseas, visit the overseas travelers’ clinic or an infectious disease clinic at least 1 month in advance to receive counseling and vaccination services (Table 9.1). For some infectious diseases, vaccines have not been developed; in such cases (e.g., malaria), taking preventive medication is necessary.

Table 9.1

Immunizations recommended for overseas travelers by the Korean Society of Infectious Diseases (Adapted from Korean Society of Infectious Diseases [13])

Types of vaccines Vaccination-required regions Characteristics of high-risk travelers Notes
Immunization is needed for entry

Yellow fever Yellow fever endemic regions in Africa and South America that require proof of yellow fever vaccination 1 dose
Request to Korean National Medical Center or quarantine station by 10 days before arrival

Meningococcus By 10 days before arrival to Saudi Arabia for pilgrimage 1 dose, combined vaccine every 5 years

Immunization generally needed to travel developing countries

Hepatitis A All developing countries All non-immune travelers (especially under 30) 2 doses (0, 6-12 months)

Typhoid India, Pakistan, Bangladesh, Nepal, Indonesia, the Philippines, Papua New Guinea People traveling for more than 2 weeks, or traveling in the countryside 1 dose every 2 years

Meningococcus Central African nations, Saudi Arabia Missionaries or medical service teams 1 dose, revaccination after 5 years

Chickenpox All developing countries Some non-immune travelers under 30 Antibody test necessary; 2 doses (0, 1-2 months)

Measles, rubella, mumps All developing countries Some non-immune travelers between 20 and 30 No antibody test necessary; single dose

Rabies South America, Mexico, Asia Researchers of animal studies, people traveling in the countryside for more than 1 month, or volunteers 3 doses

Yellow fever Yellow fever endemic areas in Africa and South and Central America Jungle explorers Single dose, request to Korean National Institute of Health or quarantine station

Polio India, Pakistan, Afghanistan, Uzbekistan, Tajikistan, African region including Nigeria Adults under 40, countryside travelers Single dose

Influenza The southern hemisphere High-risk groups for influenza traveling in the summer Single dose

Additional vaccination for non-sightseeing travel

Tick-borne encephalitis Russia, Eastern Europe Travelers staying in the forest during the summer No vaccine available in Korea

Cholera Volunteers at a refugee shelter Inactivated oral vaccine (Dukoral) preferred

Immunity test or immunization due to traveling

Refer to the standard immunization table

Fact Sheet ➌

Adhering to prevention practices for infectious diseases is the number-one component of health etiquette!

3.1 Hand hygiene: The first step for preventing infections

Hand hygiene can prevent one-third to half of respiratory infections, including influenza; epidemic eye infections; and food poisoning and enteritis accompanied by diarrhea [14].

This is because germs or viruses from the environment around us or infected people can be transmitted through our hands. Therefore, hand hygiene is the first step for caring for other people. Before and after cooking and eating, after going out, after using the restroom, and after coughing and sneezing, we must conscientiously observe hand hygiene for our own health and for that of others (Fig. 9.4).

Figure 9.4

Proper way of washing one’s hands

(Adapted from Korea Centers for Disease Control and Prevention [15])

979-11-5590-078-9-93510-ch9f4.tif

3.2 Those with symptoms of a respiratory infection, such as cough, runny nose, or fever should adhere to cough etiquette

Respiratory infectious diseases such as influenza or MERS can be transmitted through the respiratory organs as infected people cough and release the virus into the air via droplets, or through their hands or environmental contamination with the virus. Therefore, people with symptoms of a respiratory infection must be careful when coughing, so that viruses or germs do not spread into the air or the environment. People who show symptoms of a respiratory infection need to avoid going out or visiting crowded places and should wear masks. When coughing, people should cover their mouth with a tissue or handkerchief, and their face with the top of their sleeve. In addition, they should wash their hands often in order to keep the virus on their hands from spreading to other people (Fig. 9.5).

Figure 9.5

Adhere to cough etiquette

(Adapted from Korea Centers for Disease Control and Prevention [16])

979-11-5590-078-9-93510-ch9f5.tif

References

1 

DW Dockery CA Pope 3rd X Xu An association between air pollution and mortality in six U.S. cities N Engl J Med 1993 329 1753 1759

2 

CA Pope 3rd RT Burnett MJ Thun Lung cancer, cardiopulmonary mortality, and long-term exposure to fine particulate air pollution JAMA 2002 287 1132 1141

3 

B Brunekreef Air pollution and life expectancy: is there a relation? Occup Environ Med 1997 54 781 784

4 

International Agency for Research on Cancer World Health Organization IARC Monographs on the evaluation of carcinogenic risks to humans. Volume 105 Diesel and gasoline engine extracts and some nitroarenes 2012

5 

International Agency for Research on Cancer World Health Organization IARC Monographs on the evaluation of carcinogenic risks to humans. Volume 109 Outdoor air pollution 2016

6 

JH Leem ST Kim HC Kim Public-health impact of outdoor air pollution for 2(nd) air pollution management policy in Seoul metropolitan area, Korea Ann Occup Environ Med 2015 27 7

7 

World Health Organization Burden of disease from ambient air pollution for 2012 Available from URL:http://www.who.int/phe/health_topics/outdoorair/databases/FINAL_HAP_AAP_BoD_24March2014.pdf (accessed 23 April, 2017)

8 

Organisation for Economic Co-operation and Development The economic consequences of outdoor air pollution 2016 Available from URL:https://www.oecd.org/environment/indicators-modelling-outlooks/PolicyHighlights-Economic-consequences-of-outdoor-air-pollution-web.pdf (accessed 12 April, 2017)

9 

H Takano T Yoshikawa T Ichinose Y Miyabara K Imaoka M Sagai Diesel exhaust particles enhance antigen-induced airway inflammation and local cytokine expression in mice Am J Respir Crit Care Med 1997 156 36

10 

M Muranaka S Suzuki K Koizumi Adjuvant activity of dieselexhaust particulates for the production of IgE antibody in mice J Allergy Clin Immunol 1986 77 616

11 

FJ Kelly Oxidative stress: its role in air pollution and adverse health effects Occup Environ Med 2003 60 612 616

12 

DL Heymann Emerging and re-emerging infections D Roger Oxford textbook of public health 5th ed New York Oxford University Press 2009 1264 1273

13 

Korean Society of Infectious Diseases Recommendation of vaccination for travelers Available from URL:http://www.ksid.or.kr/data/sub07.html (accessed 25 April, 2017)

14 

SP Luby M Agboatwalla DR Feikin Effect of handwashing on child health: a randomised controlled trial Lancet 2005 366 225

15 

Korea Centers for Disease Control and Prevention Campaign for good hand hygiene 2017 Available from URL:http://www.cdc.go.kr/CDC/contents/CdcKrContentLink.jsp?fid=60&cid=74996&ctype=8 (accessed 13 April, 2017)

16 

Korea Centers for Disease Control and Prevention Cough etiquette 2017 Available from URL:http://cdc.go.kr/CDC/notice/CdcKrIntro0504.jsp?menuIds=HOME001-MNU1154-MNU0005-MNU2572-MNU0110&cid=74112 (accessed 1 Dec, 2017)

Notes

[1] Contributing organizations and associations:

Korea Occupational Safety and Health Agency

The Korean Society of Infectious Diseases

Korean Society of Occupational and Environmental Medicine

Contributing experts:

Kyung Taek Rim, Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency