Chapter 13. Environmental effects of air pollution

Table of Contents

13.1. The role of each pollutant
13.1.1. Carbon monoxide (CO)
13.1.2. Sulphur dioxide (SO2)
13.1.3. Nitrogen dioxide (NO2)
13.1.4. Ozone (O3)
13.1.5. Particulate matter
13.2. Some effects on the environment
13.2.1. Smog
13.2.2. Acid rain
13.3.3. Crop and forest damage by ozone

During the first part of the 20th century, due to the dramatically increasing emission of air pollutants at the same time, in the absence of environmental protection technologies, several acute air pollution episodes were formed in some countries. One of the first air pollution disasters is occurred in a heavily industrialised area of Belgium. In December 1930, during the Meuse Valley fog event, the stable atmospheric conditions and industrial pollution from steel mills, coke ovens, foundries, and smelters contributed to the significant accumulation of air pollutants including sulphur dioxide (SO2) sulphuric acid, and fluoride gases. Due to this extremely polluted air, more than 60 people died (Nemery et al., 2001). Similarly, the stable atmospheric stratification and the strong pollution from intensive industrial activity and coal-fired home led to extreme air pollution episode in Donora (United States) between 27 October and 30 October 1948. Due to this event, in the town with a population of 14000, 20 deaths, 400 hospitalizations and about 6000 respiratory symptoms were reported (Helfand et al., 2001). The London “Great Killer Fog” event in December 1952 was a consequence of the combination of coal burning during residential heating and industrial production and the unfavourable weather situation. This lethal fog in London resulted in about 3000 more deaths than normal during the first 3 weeks of December 1952, and based on the estimations, about 12000 excess deaths occurred from December 1952 and February 1953 (Bell and Davis, 2001).

Another harmful effect of increased emission of air pollutants was also recognized in the 20th century. The term “acid rain” was already introduced in 1872 by Robert Angus Smith, an English scientist, who experienced that acidic precipitation could damage plants and materials. However, acid rain was considered as a serious environmental problem only in the 1970s, when scientists observed the increase in acidity of some lakes and streams. At the same time, it became clear that the effects of air pollutants could be occurred far from the emission sources due to their long-range transport in the atmosphere.

In the last few decades, due to the emission reduction strategies and legislation, and at the same time the decline in industrial production, air quality has improved in several countries. Even so, air pollution and its effects on the environment are still severe environmental problems, particularly as some pollutants may even have long-term effects. Moreover, in some other parts of the world (especially in rapidly developing Asian countries), the situation becomes more severe due the dramatic increases in emission (Figure 13.1). Therefore, continuous monitoring of air quality by measurements and model simulations are essential.

In this chapter, we present some aspects about the effect of air pollution on the environment and the human health.

13.1. The role of each pollutant

Each pollutants emitted to the atmosphere can affect directly or indirectly the human health. Along with harming human health, air pollution can cause a variety of environmental effects, such us acid rain, eutrophication[23], effects on wildlife, ozone depletion, crop and forest damages, global climate change.

Some pollutants can also play important role in weather situations (e.g. reduction of visibility, forming of clouds and precipitation, modification of radiation budget etc.). At the same time, the state of the atmosphere is also affects the degree of air pollution through several processes (e.g. photochemical activity, transport and deposition processes etc.). Table 13.1 summarizes the possible effects of some important pollutants on the human health and on the environment.

Yearly carbon dioxide emission between 1990 and 2011 in China, USA and EU27

Figure 13.1: Yearly CO2 emission between 1990 and 2011 in China, USA and EU27. Source of data: http://edgar.jrc.ec.europe.eu

Table 13.1: Effects of some air pollutants on human health and on environment

Air pollutants

Effects on human health

Effects on environment

Carbon monoxide (CO)

headache,

reduced mental alertness,

heart attack,

cardiovascular diseases, impaired foetal development, death

contribute to the formation of photochemical smog

Sulphur dioxide (SO2)

eye irritation,

breathing problems,

cardiovascular diseases

formation of acid rain,

visibility reduction,

plant damages

Nitrogen dioxide (NO2)

irritation of the lung, respiratory symptoms, susceptibility to respiratory infections,

stoke

contribute to the formation of photochemical smog,

formation of acid rain,

visibility reduction,

water quality deterioration,

Ozone (O3)

respiratory symptoms,

eye irritation,

asthma

plant and ecosystem damage,

visible injury,

decreased productivity,

crop yield,

indirect effect on global warming

Particulate matter

asthma,

cardiovascular effects,

lung damage,

allergic disease

visibility impairment,

impacts on trace gas cycles,

cloud and fog formation, absorption and scattering radiation

13.1.1. Carbon monoxide (CO)

Carbon monoxide forms, when carbon in fuel is not burned completely (see more about CO emission in Chapter 2). CO is a colourless, tasteless, odourless and non-irritating gas. It can enter the bloodstream through the lungs and forms carboxyhemoglobyn. High concentration of carboxyhemoglobyn could be poisonous. CO poisoning cover a wide range of symptoms, depending on severity of exposure, such as headache, dizziness, weakness, nausea, vomiting, disorientation, confusion, collapse and coma (Raub and Benignus, 2002).

Due to the seasonal variation of CO emission and the weather conditions, CO concentration generally higher in winter, and lower in summer period (Figure 13.2). Based on the measurements carried out in Budapest downtown, in 2010, the concentration of carbon monoxide did not reach the occupational exposure limit.

Eight-hour moving average concentrations of carbon monoxide in Budapest, downtown, in 2010

Figure 13.2: 8-hour moving average concentrations of carbon monoxide in Budapest, downtown, in 2010 (at station “Kosztolányi Dezső tér”), based on hourly measurements by Hungarian Air Quality Network. Source of data: http://www.kvvm.hu/olm/

However, carbon monoxide can also influence indirectly the air quality. Carbon monoxide in the atmosphere as a precursor compound in tropospheric ozone formation, can contribute to the photochemical smog episodes.

13.1.2. Sulphur dioxide (SO2)

Sulphur can be found as a trace element in coal and oil. During combustion processes, sulphur combines with oxygen to form sulphur dioxide (SO2). As SO2 is relatively inert compound, it can travel long distances from its emission sources. High concentrations of sulphur dioxide can result in breathing problems. Long-term exposure of SO2 can also causes cardiovascular diseases.

Sulphur dioxide can react with ozone or hydrogen peroxide in the atmosphere, produced sulphur trioxide, which can dissolve in water, forming a dilute solution of sulphuric acid. When this strong acid reaches the surface by precipitation or dry deposition (“acid rain”), it can be damaging to organisms and objects. Due to the rigid emission reduction strategies in Europe, and in Hungary too, the SO2 emission has decreased significantly in the last decades. Figure 13.3 shows a yearly course of sulphur dioxide concentration in Budapest.

Daily average concentrations of sulphur dioxide in Budapest downtown in 2010

Figure 13.3: Daily average concentrations of sulphur dioxide in Budapest downtown in 2010 (at station “Kosztolányi Dezső tér”), based on hourly measurements by Hungarian Air Quality Network. Source of data: http://www.kvvm.hu/olm/

13.1.3. Nitrogen dioxide (NO2)

Daily average concentrations of nitrogen dioxide in Budapest, downtown in 2010

Figure 13.4: Daily average concentrations of nitrogen dioxide in Budapest, downtown in 2010 (at station “Kosztolányi Dezső tér”), based on hourly measurements by Hungarian Air Quality Network. Source of data: http://www.kvvm.hu/olm/

Nitrogen dioxide emitted to the atmosphere from transport and from power plants (more details about emission can be found in Chapter 2). The short-term exposure may cause increased respiratory symptoms, while long-term exposure can lead to irritation of the lung, susceptibility to respiratory infections, or even stroke (Andersen et al., 2012).

Nitrogen dioxide and nitric oxide (NO) too, next to the sulphur dioxide are other precursor compounds of acid rain. NO and NO2 can dissolve in water forming weak solutions of nitric and nitrous acids. Additionally, nitrogen oxides can cause several other environmental problems, such us the decrease of the visibility or eutrophication.

Urban concentration of nitrogen dioxide is still high in Hungary. A yearly course of NO2 concentration in Budapest downtown can be seen in Figure 13.4. Higher concentration was generally observed in winter season, while lower values were occurred in summer. In 2010, the concentration of nitrogen dioxide exceeds the occupational exposure limit in a few winter days at the given site.

13.1.4. Ozone (O3)

Ozone in the troposphere forms from its precursor compounds during photochemical reactions (see Chapter 8). Near-surface ozone plays an important role in the formation of photochemical air pollution. Ozone has several injurious effects both on human health (Weschler, 2006), and plant functioning (Emberson, 2003). Human exposure to ozone is associated with respiratory and cardiovascular symptoms.

Elevated ozone concentrations can be potentially harmful to agricultural and natural vegetation. Occasional extreme concentrations may cause visible injury to the vegetation while the long-term, growing-season averaged exposure can result in decreased productivity and crop yield. Recently it has also been shown that the indirect radiative forcing of climate change through ozone effecting on the land carbon sink could be an important factor and can induce a positive feedback for global warming.

Figure 13.5 and Figure 13.6 show the annual cycle of ozone concentration in a downtown and a suburb measuring stations, respectively. In contrast to other pollutants, higher ozone values appear in summer and lower ones in winter. It seems also, that in the suburb, generally larger values can be observable than in the centre of the city.

Daily average concentrations of ozone in Budapest, downtown in 2010

Figure 13.5: Daily average concentrations of ozone in Budapest, downtown in 2010 (at station “Kosztolányi Dezső tér”), based on hourly measurements by Hungarian Air Quality Network. Source of data: http://www.kvvm.hu/olm/

Daily average concentrations of ozone in Budapest, suburb in 2010

Figure 13.6: Daily average concentrations of ozone in Budapest, suburb in 2010 (at station “Gilice tér”), bases on hourly measurements by Hungarian Air Quality Network. Source of data: http://www.kvvm.hu/olm/

13.1.5. Particulate matter

Aerosol particles have various natural and anthropogenic sources (for more details see Chapter 2 and Chapter 9). Aerosol particles have important role in lower tropospheric air quality. Aerosols, especially ultra-fine particles can cause several severe health effects, including enhanced mortality, respiratory, cardiovascular and allergic diseases (see. e.g. Pöschl, 2005).

Aerosol particles can also affect significantly the cycles of atmospheric contaminants including nitrogen, sulphur, and atmospheric oxidants. Additionally they can reduce the visibility.

Higher PM10 concentrations typically occur in winter (Figure 13.7). Based on the measurements carried out in Budapest downtown station (“Kosztolányi Dezső tér”) in 2010, the PM10 concentration exceeded the occupational exposure limit in several days in winter season.

Daily average concentrations of PM10 in Budapest, downtown in 2010

Figure 13.7: Daily average concentrations of PM10 in Budapest, downtown in 2010 (at station “Kosztolányi Dezső tér”), based on hourly measurements by Hungarian Air Quality Network. Source of data: http://www.kvvm.hu/olm/

Daily average concentrations of PM10 in three different stations

Figure 13.8: Daily average concentrations of PM10 in three different stations (“Széna tér”, “Erzsébet tér” and “Kosztolányi Dezső tér”) in Budapest, downtown in 2010, based on hourly measurements by Hungarian Air Quality Network. Source of data: http://www.kvvm.hu/olm/

At the same time, elevated concentration can also formed in a few days in summer period (Figure 13.8). However, the most severe, long-term events can be realized in winter, when weather condition favours the formation of London-type smog (as it happened for example in February 2012, in Budapest).



[23] Explosive algae growth due to high concentration of nitrogen and phosporus, which can deplete oxygen in water.