Báo cáo " URBAN AIR POLLUTION IN CHINA: Current Status, Characteristics, and Progress " pdf

All rights reservedCurrent Status, Characteristics, and Progress Kebin He, Hong Huo, and Qiang Zhang Department of Environmental Science and Engineering, Tsinghua University, Beijing 100

° 2002 by Annual Reviews All rights reserved

Current Status, Characteristics, and Progress

Kebin He, Hong Huo, and Qiang Zhang

Department of Environmental Science and Engineering, Tsinghua University,

Beijing 100084, China; e-mail: hekb@mail.tsinghua.edu.cn, huohong@pm25.org,

zhangqiang@pm25.org

Key Words Chinese cities, urban air quality, atmospheric pollutants, control

strategies, Beijing

■ Abstract China is rapidly developing as evidenced by enhanced urbanization

and industrialization and greatly increased energy consumption However, these have brought Chinese cities a variety of urban air pollution problems in recent decades Dur-ing the 1970s, black smoke from stacks became the characteristic of Chinese industrial cities; in the 1980s, many southern cities began to suffer serious acid rain pollution; and recently, the air quality in large cities has deteriorated due to nitrous oxides (NOx), car-bon monoxide (CO), and photochemical smog, which are typical of vehicle pollution Some cities now have a mixture of these Urban air pollution influences both the health

of citizens and the development of cities To control air pollution and protect the atmo-spheric environment, the Chinese government has implemented a variety of programs This paper first reviews the current status of air quality in Chinese cities, especially key cities, then describes the characteristics of some major urban air pollutants, includ-ing total suspended particles (TSP), respirable particles 10 microns or less in diameter (PM10), very fine particles 2.5 microns or less in diameter (PM2.5), sulfur dioxide (SO2), acid rain, NOx,and photochemical smog Two specific topics, SO2and acid rain control and vehicle emission control, are used to illustrate the actions that the government has taken and future plans Finally, a case study of the Chinese capital, Beijing, is presented with a discussion of its main air pollution problems, recently implemented control mea-sures and their effects, and future strategies for urban air quality improvement

CONTENTS

INTRODUCTION 398

OVERVIEW OF CURRENT URBAN AIR QUALITY STATUS 401

CHARACTERISTICS OF URBAN AIR POLLUTANTS 404

TSP 404

PM10and PM2 5 407

SO2 409

Acid Rain 410

NOx 411

398 HE ¥ HUO ¥ ZHANG

O3and Photochemical Smog 414

Indoor Pollutants 414

ECONOMIC DAMAGE 416

CONTROL PROGRESS AND PROSPECTS 418

SO2Pollution and Acid Rain Control 418

Vehicle Emission Pollution Control 422

Beijing—A Case Study for Urban Air Pollution Control in China 424

CONCLUSION 427

INTRODUCTION

China has achieved rapid economic growth, industrialization, and urbanization in recent decades, with the annual increases in GDP of 8%–9% (1) Cities, as a kind

of hallmark for progress, have played a significant facilitating role in Chinese eco-nomic and social development Since the Open Policy, the urbanization of China has accelerated with the proportion of urban population to the total population in China increasing from 18% in 1978 to 31% in 1999, a growth rate three times the world average during this period (1–3) By the end of the twentieth century, the explosion in economic growth also made China the world’s second largest energy consumer after the United States Energy consumption, especially coal consump-tion, is the main source of anthropogenic air pollution emissions in Chinese cities Since the late 1970s, the total energy consumption has greatly increased from 571 million tonnes of coal equivalent (Mtce) in 1978 to 1220 Mtce in 1999 (Figure 1) (1) Coal, the primary energy source, accounted for about 74% of the total energy consumption during this period, and its use is the origin of many air pollution prob-lems, such as TSP pollution, SO2pollution, and acid rain Crude oil consumption has increased with the average growth rate of 6% per year in the past decades Part of this increase is due to the rapid expansion of motor vehicle fleets This has heightened ambient pollution by NOx, CO, and related pollutants in large cities (4, 5)

China’s growing energy consumption, reliance on coal, and rapidly increasing vehicle population place a heavy burden on urban atmosphere in China, and urban air pollution is rapidly emerging as a major environmental issue Many cities have suffered from increasingly serious air pollution since the 1980s At the early 1990s, less than 1% of over 500 cities in China reached Class I (the least serious of three levels) of the national air quality standards (6) During the 1990s, some megacities, such as Beijing, Shenyang, Xian, Shanghai, and Guangzhou, were always listed among the top 10 most polluted cities in the world Urban air pollution in China and has probably caused significant public health effects and economic damage

To protect public health and environmental quality, the Chinese government has undertaken a series of actions including:

1 The promulgation of laws, regulations, and standards The environmental policy decision-making system of the Chinese government consists chiefly of three

city levels are directly under the SEPA On September 15, 1987, the Law on Air

Pollution Prevention and Control of the People’s Republic of China (LAPPC) was

approved by the NPC The law required that all plants that discharge pollutantsinto the air must comply with the rules for pollution control After that, the Chinesegovernment published a series of policies and regulations for air quality protectionand established a set of national standards related to air quality, which are discussed

3 Implementation of research and development programs for urban air pollutioncontrol The Chinese government initiated a series of research and developmentprograms involving studies analyzing urban atmospheric pollutants, atmosphericmodeling, environmental planning, development of advanced technologies, anddemonstration studies of urban air pollution control Also, many internationalorganizations and foundations, such as United Nations Development Programme(UNDP), U.S Environmental Protection Agency (USEPA), World Bank, U.S.Energy Foundation, and others, have provided financial and technological support

to help strengthen the capacity of Chinese experts and researchers to solve urbanair pollution challenges for themselves

4 The investment in environmental infrastructure, including pollution controldevices, cleaner production technology, and natural gas pipelines

These actions have prevented China’s urban atmospheric environment from teriorating This review discusses the current status, characteristics, and progress ofthe urban air pollution controls in China, based on the results of the aforementionedactions

de-OVERVIEW OF CURRENT URBAN AIR QUALITY STATUS

On October 1, 1996, the Chinese National Ambient Air Quality Standards

(CNAAQS, GB3095-1996) were published, which specify 10 air pollutant dards for SO2, TSP, PM10, NOx, nitrogen dioxide (NO2), CO, ozone (O3), Pb,B[a]P, and F (Table 1) According to these standards, cities should meet Class II

stan-of the CNAAQS, which is considered to be safe and acceptable (9)

At present, the urban air pollution in China, especially for northern cities, is

mainly from coal smoke with particles According to the Report on the State of the

Environment in China for 2000, 62% of the cities exceeded Class II of the CNAAQS

for TSP and PM10concentrations SO2pollution has improved somewhat with thepercentage of cities exceeding Class II of CNAAQS decreasing from 28% in 1999

to 22% in 2000 The NOxpollution level was relatively low in most cities except inlarger ones with better economic development and more vehicles, such as Beijing,Guangzhou, and Shanghai, where the pollution is a mixture of coal smoke andvehicle exhaust Generally speaking, urban air quality in China is improving withthe percentage of cities meeting Class II of the CNAAQS increasing for over

300 cities as shown in Figure 2 (10)

During the ninth five-year plan (1995–2000), China focused on 47 sites as keyenvironmental protection areas (4 municipalities, 28 provincial cities, 15 specialeconomic regions, open coastal cities, and major tourist cities, which togetheraccount for 40% of the total urban population and 60% of the total urban GDP).The air quality data of cities is public information Beginning in June 1997, manylarge cities began to publish weekly air quality reports by using an air pollutionindex (API) and an air quality level In June 2000, daily air quality reports replaced

TABLE 1 Concentration limits for some pollutants in theCNAAQS (mg/m3)

TABLE 2 Relationship of concentrations and subindex of somepollutants (mg/m3)

In China, each pollutant reported has a subindex ranging from 0 to 500, with

50 corresponding approximately to Class I of the CNAAQS, 100 corresponding

to Class II, 200 corresponding to Class III, and 500 corresponding to significantharmful effects Table 2 gives the relationship of concentrations and subindexes

of some pollutants Based on the ambient measurement results, the subindexes inTable 2 are computed by using linear interpolation

Initially, air quality reports for many Chinese cities published the levels of threemajor pollutants, TSP, SO2,and NOx Since February 2000, the air quality reportsfor many cities listed the API value of PM10, NO2, and SO2; the first two of thesehave been found to have more direct influence on public health than TSP and NOx.However, air pollution reporting varies according to local government policies Forexample, Beijing reports CO and O3levels in addition to the other three pollutants.For a city, the API of a week or day is the maximum of the subindexes ofpollutants reported, and the pollutant with the highest subindex is cited as themajor pollutant A level and an assessment of the general air quality, based on thereported API, are also included in the air quality reports The levels and assessmentsalong with their associated API ranges are presented in Table 3

Figure 3 summarizes the average monthly API values of eight regions in China,based on the daily air quality reports of 42 key cities from June 5, 2000 to Septem-ber 30, 2001 (11) Significant regional air quality differences are evident in China.The most polluted cities were located in the northwest and north The south-central and northeast regions ranked third and fourth, followed by the east andsouthwest The cleanest region was the south followed by the southeast with theAPI values of both almost always less than 100 all year Urban air in northernChina was generally more polluted than in the south mainly due to the higherparticulate matter pollution levels in the north There was also an obvious sea-sonal variation in urban air quality For all regions, summer and fall were the

of the atmospheric pollutants—especially particulate matters After October, theair quality of most cities began to deteriorate and pollution peaked in the winter.

In northern cities, bad air quality in the winter was probably because of the largeamount of coal burned for heating, which emited high levels of pollutants Thewinter peak was the sharpest for the northeast region where it is the coldest InFebruary, the air quality improved some, but another pollution peak occurred inMarch or April The spring peak in northern cities was due to the sandstormsfrom the west The northwest region, which experienced the heaviest burden ofsandstorms, had the sharpest and highest spring peak

Figure 4 shows the air quality level in each of 42 key cities from July 1, 2000 to

June 30, 2001 As shown in Figure 4a, during this statistical year, only about 30%

of the 42 key cities met the Level II air quality most of the time In the Chinesecapital, Beijing, the pollution on more than half of the 365 days exceeded the LevelIII air quality as it did in other big cities, such as Tianjin and Chongqing In thenorthern cities of Lanzhou, Taiyuan, and Shijiazhuang, the air quality was so poorthat Level III was exceeded more than 75% of the year, and Level V pollution

frequently occurred According to Figure 4b, PM10was the dominant pollutant inmost cities SO2was the major pollutant in Chongqing and Guiyang and was aconcern in Shijiazhuang, Changsha, Qingdao, and other cities

CHARACTERISTICS OF URBAN AIR POLLUTANTS

Figure 5 Average annual urban TSP concentration in China from 1990–1999.

coal smoke that “rolling black smoke” was a common phrase to describe the air.The emphasis on urban air pollution control at that time was smoke abatementand dust removal, with boilers refitted and “nonblack smoke zones” established

In the 1980s, improvements were seen with lower smoke and dust levels In the1990s, the control emphasis turned to the abatement of particles from residentialcoal burning, with regulations requiring the use of briquettes and for optimization

of the residential fuel structure by using gas, electricity, and oil to replace coal

As total energy consumption increased in recent years, the average urban TSPconcentration gradually declined, which illustrates progress in urban TSP control.The average annual rate of decrease in the national average TSP concentrationsfor over 70 cities was 4% during the 1990s, as shown in Figure 5 The rate of theaverage TSP concentration decrease in 4 municipalities1and 24 provincial cities(including 14 northern cities and 14 southern cities) was 3% (12)

As Figure 5 shows, the urban TSP concentration in the north was much higherthan in the south This was due to many factors The colder north burns muchmore coal for winter heating, and its lack of vegetation and aridness give rise tohigh concentrations of large-diameter, nonrespirable sand or loess soil particlesblown from the west each spring The effects of these natural factors make control

of TSP pollution in northern cities difficult, so the TSP concentration in the north

is decreasing more slowly than in the south Moreover, the north has more heavyindustry, which emits particulate matter

1Chongqing, which was removed from Sichuan Province and promoted to the status of aprovincial-level municipality in 1997, is reckoned in as a municipality

Because many effective measures have been implemented to reduce the late matters emitted from boilers, the contribution of coal smoke dust to urban TSPhas decreased As the coal smoke pollution in urban air gradually decreased, somenonpoint sources, such as soil, road particles, and construction dust contributed alarge percentage (13–15) Many modeling studies of the source apportionment ofurban TSP have been implemented in China, especially for the northern cities Inthe north, particulate soil matter has become the largest part of the TSP, with anaverage level of 40% to 50% due to the dry climate and low level of forestation

particu-in the area (16, 17) Remote sources of soil particulates also contribute a lot to thenorthern cities During springtime, 20% of the TSP mass was from outside in Xiancity (18) Therefore, the TSP concentrations have remained high in northern citieseven after implementation of TSP control measures, and soil-dust control in thenorth remains a challenge During the northern heating period, the burning of coalelevates the percentage of coal smoke dust in the urban TSP up to 30% to 40%.The high share of coal smoke particles during the winter and the soil dust duringspring are common features of the TSP in the north but not in the south (19–22)

2In this paper, large cites have population>1 million, medium cities are 0.5–1 million, andsmall cities are<0.5 million

3For Figures 6 and 7, 12 large, 12 medium, and 12 small cities were chosen

PM10and PM2.5

Particulate removal techniques currently in use in China are effective with coarserparticles but do not remove small particles very well; this has caused the TSP inurban air to become finer and the PM10portion to grow For example, in Beijing,about 92% of the TSP in coal smoke dust is less than 10 microns (23) Not onlydoes PM10predominate among urban air particles, but concerns over its impact onhealth have caused researchers and government officials to focus more attention

on it than ever In 1996 the PM10standard was added to the CNAAQS, and in 2000

PM10replaced TSP in the air quality reports of many cities

Fine particles contain a large component of organic and toxic materials and canenter and remain in the human body more easily than coarse particles and affecthuman health These particles reduce the visibility in cities and influence daily life.The acidity and buffer capacity of the particles also influences acid rain The UnitedStates published an air quality standard for PM2.5in 1997, but in China only a fewresearch projects have analyzed urban PM2.5(24–26) According to these studies,the PM2.5pollution level in Chinese cities is 1 to 5 times higher than the U.S.standard of 65µg/m3, and PM2.5is the largest portion of PM10, 50%–85% of thetotal in terms of mass (Figure 7) The urban PM2.5concentration also varies withseasons For example, the PM2.5concentration in Beijing was highest during thewinter, decreased through the spring, and tended to be lowest during late spring

to early fall (24) The sources of PM10 and PM2.5are much more complicatedthan that of TSP Human activity is the main source of fine particles in cities For

PM2.5, the ratio of anthropogenic contribution to natural contribution was 10–15:1

Figure 7 PM2.5and PM10concentration in the cities Guangzhou, Wuhan, Lanzhou,and Chongging in 1996

Figure 8 presents the chemical composition of PM2.5 in terms of mass inBeijing Carbon was the main component due to the large contribution of coaland oil consumption The proportions of NH+

4, SO2−

4 , and NO−

3 were very high,about 30%–40%, which indicates that the acidity of urban PM2.5is strongly in-fluenced by secondary particles Atmospheric NH3, as an important precursor tosecondary particles, reacts with SO2and NOx According to studies of the ammo-nia level in China, the biggest contributors are livestock (which contributes about30%–60%) and the application of nitrogenous fertilizer (which contributes about17%–47%) (29–32) The characteristics of these sources determine the tempo-ral and spatial NH3distribution The ammonia concentration in northern cities isrelatively high during the spring and summer farming period, while in southerncities no obvious seasonal variation occurs because the farmland is worked duringall four seasons In addition to NH3, the relative humidity, the temperature, andthe insolation are also important factors influencing the formation of secondaryparticles But the interactions between these factors are so complex and the meth-ods used by researchers are so dissimilar that no uniform result is forthcoming

In Beijing, some research has shown that the concentration of secondary particlesseems to be higher in the winter probably due to the high SO2emissions and lowwind speed at that time, which aid the formation of SO2−

4 , and the low ture, which assists the oxidation of NOxto NO−

tempera-3 Other research has shown thatsummer has the highest secondary particle concentration—not winter—because

of the large NH3emissions and sufficient temperature and humidity to ensure theoxidation of SO2to SO2−

4 (24, 30)

The enrichment by toxic materials, such as manganese, nickel, copper, zinc,selenium, and lead, was substantially greater in PM2.5than in coarser particles,which indicates that urban pollution sources provide a much larger contribution to

PM2.5 The lead concentration was fairly low in Beijing, largely below Class II ofthe CNAAQS because leaded gasoline has been banned (24, 25)

SO2

SO2is not only an important precursor of acid rain and secondary particles, but itcan also severely impair public health As shown in Figure 9, SO2pollution wasvery serious in the early 1990s The concentration value has since dramaticallydecreased at an annual rate of 6% During the same period, the annual rate ofdecrease in the average SO2concentration of 4 municipalities and 24 provincialcities was 5% The constant SO2concentration decrease shows that SO2pollution

is now well under control (12)

The geographical distribution of SO2pollution is somewhat different than theTSP distribution The SO2pollution level in northern cities is approximately thesame as in the south, but SO2 concentration declined more rapidly in southerncities Figure 10 shows that the SO2 pollution was extremely serious in largecities, well above Class II of the CNAAQS, but SO2control measures have beenrapidly reducing the SO2concentration in them For example, SO2concentration

in the heavily polluted cities of Guiyang, Chongqing, Qingdao, and HangZhouwas reduced by about 50% during the 1990s

The SO2 pollution in cities is a local environmental problem, which resultsmainly from industrial production, energy transformation, and residential cooking

Figure 9 Average annual urban SO concentrations in China from 1990–1999

to reducing SO2emissions is to control the SO2 emitted from coal combustion(33, 34).

Acid Rain

Acid rain was recognized as a potential environmental problem in China in thelate 1970s and early 1980s In the early 1980s, acid rain primarily occurred in tworegions Chongqing-Guiyang and Nanchang In the 1990s, the southeast coastalarea (Fuzhou, Xiamen, and Shanghai), the north coastal area around Qingdao inShandong Province, and the northeast area around Tumen in Jilin Province werealso identified as acid rain areas Now, acid rain is mainly dispersed south of theYangtse River and in coastal regions, including many southern cities in Guangdong,Guangxi, Sichuan, Guizhou, Yunnan, Hunan, Jiangxi, Fujian, Zhejiang, Jiangsu,and Anhui, as well as the Shanghai and Chongqing Municipality, and a few northerncities such as Qingdao and Tumen About 40% of China suffers from acid rainpollution, Figure 11 (35–37)

The ratio of the equivalent concentration of SO2−

4 to that of NO−

3 averages about4–15, which is quite different from other acid rain areas in the world In the UnitedStates, Europe, and Japan, the SO2−

4 to NO−

3 contribution ratio is about 1–2.5 Thedifference is mainly due to the large amount of coal consumed in China (38, 39).The SO2level in acid rain is now decreasing so the average ratio of [SO2−

4 ] to[NO−

3] is decreasing because of the SO2 emission reduction measures and theemission of more NOxfrom vehicles (40)

Acid rain has been observed in southern China but not in most of northern China,although there are stronger emissions of the precursors, SO2and NOx,in the north.The difference may be due to the alkaline soils and meteorological conditions

As stated earlier, the contribution of soil dust to urban particulate matter in thenorth is larger than in the south Furthermore, the northern soils are much morealkaline, which neutralizes acidic ions such as SO2−

4 and NO−

3 in the rain Highertemperatures and the humid climate in the south also facilitate transformation of the

SO2and NOxto sulfate and nitrate Good atmospheric dispersion in the north helps

to mix and transport pollutant emissions over large areas (41) Simulations showthat the ratio of sulfur emissions to sulfur deposition is much less than 100% inmost northern cities, which indicates that some of the emitted SO2was transportedand deposited in other regions (40)

NOx

The average NOxconcentration in China did not vary much in the past decade andwas consistently under Class II of the CNAAQS (Figure 12) The average NOxconcentration in the north was higher than in the south For the whole country,

NOxpollution is relatively low, but some large cities face extremely serious NOx

Figure 12 Average annual urban NO concentrations in China from 1990–1999

412 HE ¥ HUO ¥ ZHANG

Figure 13 Annual NOxconcentrations in some large cities from 1990–1998

levels As Figure 13 shows, broadly speaking, the NOxconcentration in these fourlarge cities gradually increased in the 1990s and greatly exceeded Class II of theCNAAQS In Guangzhou and Beijing, the NOxlevel even dramatically exceededthe Class III standard Table 4 also shows that larger cities had higher NOxpollutionlevels than smaller ones (42)

Vehicles are the main contributor to the urban NOx Since the late 1970s, thevehicle population in China has grown extremely rapidly, increasing about 10-foldduring the past two decades By the end of 1998, the total number of vehicles hadreached about 40 million (including motorcycles) The increase is more obvious

in the large cities In Beijing, the average growth rate was 17.4% in the 1990s with

TABLE 4 NOxpollution level in different size cities in China, 1994 and 1998

Average NO x

the vehicle population reaching 1.45 million in 1999 In Guangzhou, the ber of vehicles reached 1.10 million in 1999 (43, 44) However, road constructionhas not been able to keep up with the significant increase in the number of ve-hicles In Guangzhou, the average growth rate of vehicle population was morethan 20%, but the growth rate of road length and road area was only 13%–14%during 1990–1995 (45) Slow increases in transportation infrastructure greatly ex-acerbated the vehicle emission problem In Beijing and Guangzhou, the averagevelocity of vehicles on main roads in the daytime is below 20 kilometers per hour(46).

num-Vehicles not only emit large quantities of NOx, but they also produce largeamounts of carbon monoxide (CO) and volatile organic compounds (VOCs), both

of which are important pollutants in urban air In Beijing, the NOxand CO sions from vehicles were 0.12 million tons and 1.3 million tons in 1998 Table 5lists the percentage of emissions and pollutant concentrations due to vehicles inthree large cities (47–50) NOx, CO, and VOC concentrations were highest in thedense traffic parts of the cities, especially during the rush hours The emissionlevel of NOxinside the second ring of Beijing was about four times that beyondthe fourth ring (The second ring is closer to the center of the city than the fourthring.) In cities, two peak vehicle pollution levels occur during each day, one fromabout 8:00–10:00 and the other from 15:00–17:00, which correspond to rush hours(51, 52)

emis-The average emission levels of new domestic vehicles are 3–10 times higher thanthat in developed countries due to lagging automotive manufacturing technology,poor fuel quality, poor vehicle exhaust control, and lenient laws limiting vehi-cle emissions In addition, bad traffic management, poor maintenance, and slowinfrastructure development have exacerbated the emission problem, all of whichexplain how a relatively small vehicle population can emit very large amounts ofpollutants in Chinese cities

TABLE 5 Contribution of vehicles to emissions and concentration of urban

414 HE ¥ HUO ¥ ZHANG

O3and Photochemical Smog

The NOxand VOC emissions from vehicles can further react in the air and formsecondary pollutants such as O3 and peroxyacetyl nitrate (PAN) The combina-tion of these pollutants leads to the formation of photochemical smog, which isstrongly oxidizing and can seriously impair human health and the environment.Besides the precursors, the formation of photochemical smog principally requiresambient temperatures above 20 centigrade, wind speeds lower than 3 m/s, andintense sunlight (53) So, at midday during the summer or early fall, if the mete-orological conditions are right, photochemical smog will probably occur in citieswith abundant precursors In the late 1970s, photochemical smog first appeared inthe Xigu petroleum industry district in Lanzhou In 1986, Beijing also experiencedphotochemical smog in the summer There the O3level gradually increased later inthe day exceeding Class II of the CNAAQS and increased from 188 in 1991 to 777

in 1999 (54, 55) More recently, some southern cities, especially coastal cities, havefaced the threat of photochemical smog in the summer Shanghai, Guangzhou, andShenzhen have frequently experienced photochemical smog pollution A signifi-cant property of photochemical smog in China is the high ratio of NMHC to NOx,which has an average value above 100, indicating that the O3formation is verysensitive to the NOxconcentration Therefore, the NOxlevel must be controlled toreduce the O3(53)

Indoor Pollutants

Energy used by households in the cities is an important component of China’senergy consumption and is 7%–10% of the total commercial energy consumed inrecent years (4, 5) Space heating and cooking are the major energy uses in thehousehold They account for 75% of the residential energy consumption in China,with space heating dominating all other types of energy use in the home Threequarters of the floor area in urban residential buildings were heated by stoves withefficiency of less than 10% (56, 57) In the 1980s and the early 1990s, coal providedmore than 80% of the total urban residential energy and contributed significantly

to indoor air pollution But the percentage has been declining with the proliferation

of gas fuel (including natural gas, coal gas, and liquefied petroleum gas), largely as

a result of government investments (Figure 14) In 1999, 80% of urban homes hadaccess to gas for cooking, and coal-burning households were increasingly turning

to the use of cleaner, more efficient briquettes (1)

A recent series of studies showed that indoor air pollution is very serious inurban China The research results in Shanghai and three other cities confirmedthe expected result that concentrations of inhalable particulates (IP), SO2, NO2,and CO, in the homes using coal were much higher than in the homes consuminggaseous fuel (Table 6) The difference between the SO2, IP, and CO concentrationscaused by the two types of fuel used could reach a multiple of more than 10 timesduring the winter, although the NO2concentrations were somewhat higher in thehomes fueled by gas than those fueled by coal The concentrations of pollutants in

416 HE ¥ HUO ¥ ZHANG

TABLE 6 Changes in the average concentration of indoor pollutants by using different fuelsduring the winter (mg/m3)

SO 2 NO 2 CO IP Fuel Coal Gas Ratio Coal Gas Ratio Coal Gas Ratio Coal Gas Ratio

Taiyuan 0.283 0.166 1.7 0.101 0.622 0.2 5.91 7 0.8 1.173 a 0.386 a 3.0 (58)

Yinchuan 0.394 0.372 1.1 0.157 0.154 1.0 — b — — 0.853 0.372 2.3 (59)

Guangzhou 0.487 0.038 12.8 0.062 0.076 0.8 18.19 3.24 5.6 0.706 0.424 1.7 (60)

Chengde 0.482 0.163 3.0 0.068 0.084 0.8 7.39 4.69 1.6 0.665 0.209 3.2 (61)

(61)

Shanghai 0.86 0.065 13.2 0.1 0.04 2.5 14.07 3.45 4.1 0.384 0.148 2.6 (61)

Wuhan 0.173 0.07 2.5 0.094 0.115 0.8 3.46 4.83 0.7 0.291 0.204 1.4 (61)

a Data are for TSP.

b No data are available for the items with a dash.

kitchens were much higher than those in bedrooms With regard to different kinds ofheating systems, separate ones (with small coal stoves) in individual residence unitscause higher indoor pollution than central heating systems during the winter (57).The residential cooking and heating also emits a great amount of polycyclic aro-matic hydrocarbons (PAHs) Some studies investigated the composition of PAHsand concluded that high indoor concentrations of PAHs (2–30µg/m3) were mainlycaused by household cooking and heating activities, and a high concentration ofB[a]P (5–19µg/m3) was mainly from smoking (62, 63)

Other important contributors to indoor air pollution are new building materialsand furnishings, which generally emit VOCs at a much higher rate than oldermaterials Because of concerns about the health effects of VOCs, in 2002 theChinese government implemented 10 national standards for limiting toxic subjects

in building materials and furnishings

ECONOMIC DAMAGE

Estimates of economic losses from air pollution can provide useful informationfor environmental policy making Table 7 lists the direct economic losses of air

pollution accidents according to the China Environment Yearbook (12) These

statistical results are only a part of the economic losses caused by air pollution The