Table 2 Summary of studies emphasizing methodological characteristics.

Zmirou et al [18]

PM₁₀

Morbidity: Asthma & other respiratory conditions or symptoms.

Direct medical costs: Drug consumption, medical and other health professionals' care, biological or radiological examinations, daily hospital costs.

Indirect costs: Work absence due to illness (adult males), work absence for child care (mothers), days of school absence.

(Wage losses have converted into average daily wage losses.)

Method: A figure of 970,000 inhabitants (three cities in France) is multiplied by the average unit cost of asthma & other respiratory conditions.

Production loss (due to morbidity) is valued using HCA. VOSL is used to evaluate premature mortality cost.

Not stated

Voorhees et al [19]

Nitrogen dioxide (NO₂)

Morbidity: Phlegm & sputum in adults, lower respiratory illness in children.

Direct costs: Direct medical costs.

Indirect costs: Costs of lost workers' wages, costs due to mothers' wage losses due to caring for sick children.

Method: Average cost is multiplied by population.

Production loss is valued using work days lost (including mothers' workdays lost due to looking after sick children) multiplied by wage.

Not stated

Panis [23]

SO₂, NO_x & PM

Morbidity: Respiratory minor illness, serious respiratory & cardiovascular illness

Not stated separately

Method: Adopted Impact path way approach from ExtrenE Project

N/A

Not stated

Navrud [22]

PM₁₀, PM _2.5, NO_x, O₃

Morbidity: Seven light symptoms

Direct Costs: medication, Doctor's & hospital visits

Indirect costs: cost of wage earning lost due to RADs & mortality

Intangible cost: restricted leisure activities

Method: Intangible costs are estimated using CVM

N/A

Not stated

Rozan, [20]

Air pollution (the specific pollutant was not identified)

Morbidity: Minor illness only, hospitalization not relevant.

Direct costs: Medical treatment.

Indirect costs: Wage loss due to sick leave.

Intangible costs: Pain, suffering, loss of opportunity to practice leisure activities due to illness.

Method: Intangible costs are estimated using CVM.

Production loss is valued using HCA.

Not stated

Neidell [21]

Carbon monoxide (CO)

Morbidity: Asthma (children).

Direct costs: Hospitalization costs.

Method: Average charges for ER admission for asthma are multiplied by the number of admissions.

N/A

Not stated

DSS Management Consulting inc. [24]

Ozone & PM₁₀

Morbidity: Respiratory & cardiovascular illness.

Direct costs:

Hospital admission, emergency room visits, doctor's room visits, medication, mortality.

Indirect costs: Lost productivity.

Intangible costs: Value of pain & suffering.

Method: To estimate the total cost, the total population of Ontario is multiplied by the average cost.

HCA.

Not stated

Vergana and the Mexico Air Quality the WB study [25]

PM₁₀ & Ozone

Mortality.

Morbidity: Respiratory diseases (cardiocerebrovascu-lar, congestive heart failure), Asthma.

Chronic morbidity: Chronic bronchitis & chronic cough, prevalence (children).

Direct costs:

Medication, hospital admission, emergency room visits.

Indirect costs: Restricted activity days, work days lost (adults), work days lost by women due to RAD in children.

Method: To estimate the total cost, the population of 17 million is multiplied by the average cost.

To estimate premature mortality cost, this study has followed ExternE(1999) approach. & assumed the number of premature deaths equal to Years of Life Lost (YOLL) about 0.75 years.

3%

Larson et al [45]

PM₁₀

Mortality risks.

Indirect costs of mortality.

Method: Among Volgograd's population of 50,000 people, the annual number of deaths is estimated at 2666.88. Annual mortality costs were multiplied by the total population in order to obtain the total costs of mortality.

VOSL is estimated using HCA.

10%

Alberini & Krupnick [1]

PM₁₀

Morbidity: 19 minor respiratory-related symptoms such as cold, sore throat, headache, eye irritation, etc.

Direct health care costs: Doctor's fees, prescription medication.

Indirect health care costs: Earning loss due to absenteeism, restricted activity days.

Method: To estimate the total COI, average unit cost associated with every cost components (i.e. doctor's visits Medication costs, and earning lost) are multiplied with total number of adult residents of three Taiwan's cities and has added them together.

Work days losses are estimated using HCA. WTP is used to evaluate premature mortality.

Not stated

Srivastava & Kumar [2]

NO₂, CO, HC, PM (below 10 Micron)

Mortality and Morbidity:

Chronic bronchitis, bronchitis in children, asthma, respiratory symptoms & illness.

Direct costs:

Emergency room visits, hospital admission.

Indirect costs:

Loss of salary due to mortality & restricted activity days.

Method: Average income loss due to morbidity & mortality is multiplied by the total population.

Production losses are estimated using HCA, WTP was used to estimate the monetary values of premature mortality, and cost is evaluated using VOSL.

5%

Quah & Boon [50]

PM₁₀

Mortality.

Morbidity: Asthma, respiratory symptoms, lower respiratory illness (LRI) in children, chronic bronchitis.

Direct costs for morbidity: Emergency doctor's room visits, Hospital admission.

Indirect costs: Premature mortality & restricted activity days.

Method: Unit costs are multiplied by population.

Production losses due to morbidities are estimated using HCA, WTP is used to estimate the monetary values of premature mortality, and cost is evaluated using VOSL.

3%

Resosudarmo & Napitupulu [48]

PM₁₀, NO₂, SO₂

Premature mortality.

Morbidity: Asthma attacks, chronic bronchitis, respiratory symptoms in children, chest discomfort in adults.

Direct costs: Hospital admission, emergency room visits.

Indirect costs: Cost of premature death & restricted activity days.

Method: Average cost per case is used to estimate the direct cost.

Both of HCA &VOSL are used (Mortality cost is evaluated using VOSL).

5%

Kan & hen [46]

PM₁₀

Premature mortality.

Morbidity: Asthma attacks (children and adults), chronic bronchitis, Acute bronchitis, respiratory illness, cardiovascular disease.

Direct costs: Hospital admission, outpatient visits, medication.

Indirect costs: Cost of premature death & restricted activity days.

Method: Both COI and WTP are used to estimate the direct & indirect costs.

WTP is used to estimate the monetary values of premature mortality and cost is evaluated using VOSL.

Not stated

Deng [47]

PM₁₀

Mortality.

Morbidity: Respiratory diseases, Cardiovascular, Lower respiratory infection/child asthma, Asthma (adult), Bronchitis, Chronic bronchitis Respiratory symptoms

Direct costs: Hospital admission, outpatient visits, emergency room visits.

Indirect costs: Cost of premature death & restricted activity days.

Method: Both COI and WTP are used to estimate the direct & indirect costs.

The study has adopted VOSL from WHO's estimation and then adjusted it by the ratio of Beijing's per capita GDP

Not stated

Saksena & Dayal [49]

PM₁₀

Premature death.

Morbidity: Respiratory symptoms, lower respiratory illness, asthma, chronic bronchitis

Direct costs: Hospital admission, emergency doctor's room visits.

Indirect costs: Cost of premature death & restricted activity days.

Method: Total population is multiplied by the unit values of health damage.

Both of HCA &VOSL are used (Mortality cost is evaluated using VOSL).

5%

Report of Environment protection Department, Hong Kong [57]

NO₂, SO₂, Rsp, & Ozone (O₃)

Mortality & Morbidity:

Respiratory diseases, cardiovascular diseases

Direct costs: Self medication & any other related expenses,

Hospital admission, consultation fees (public and private), registration charges.

Indirect costs: Wage loss due to illness & mortality.

Method: Both COI and WTP are used to estimate the direct & indirect costs.

HCA.

Mortality cost is evaluated using VOSL

7%