Moscow Smog of Summer 2002. Evaluation of Adverse Health Effects 25

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Moscow Smog of Summer 2002.

Evaluation of Adverse Health Effects

Victor Kislitsin · Sergey Novikov · Natalia Skvortsova

Abstract

Th e Moscow extreme event in Summer 2002 was not marked by a strong heat-wave, as seen in Europe during 2000 – 2003, although three-to-four heat-waves (temperature 28 – 32 °C) lasting for four to six days each were observed. Th e main cause of concern was the presence of a haze and a smell of burning for many days together with high concentrations of pollutants produced by the forest and peat bog fi res and industrial and vehicle emission. Due to the lack of appropriate and timely data on health outcomes of the smog at that time, the Ministry of Health and the Moscow Authority asked the Institute of Human Ecol- ogy and Environmental Hygiene to evaluate quickly possible adverse health eff ects caused by the smog.

Th e information was needed for further decision-making in an eff ort to overcome the consequences of the smog. Th e present article describes the adverse health eff ects that the pollutants of concern may cause, and presents measured pollutant concentrations and evaluated adverse health outcomes of the smog air pollution.

Key words

smog, air pollution, air pollutant concentration, health risk assessment

Introduction

Th e impact of chemical compounds produced by forest and peat bog fi res together with excessive in- dustrial and vehicle emissions on the health of the urban population has been observed for many times in diff erent regions of the Russian Federation and all over the World (for example, Canada, USA, India, Indonesia and others).

Two kinds of smog have been distinguished. According to Berlyand (1975), the London smog is usu-

ally observed in the early hours in wintertime with calm weather where the temperature is between –1 °C

and –4 °C and relative humidity is more than 85 %. Th e distinguishing feature of the London smog is very

restricted visibility (less than 30 m). Photochemical smog (frequently observed in Los Angeles, USA) usu-

ally takes place in the middle of the day during the months of August through to September. It is character-

ised by a wind speed of less than 3 mps, ambient temperature between 24 °C and 32 °C, relative humidity

less than 70 % and visibility range of between 1.5 and 8 km.

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256 25 Moscow Smog of Summer 2002. Evaluation of Adverse Health Eﬀ ects

Moscow smog

In July through to the middle of September 2002, there was an extreme weather situation in Moscow similar to the smogs seen in Los Angeles, USA. It was caused by a long-lasting anticyclone that brought high temperatures (up to 32 °C) and small amounts of precipitation (for the period May to September 2002 there were 150 mm, compared with the normal level of 350 mm), many calm days and low humidity (40 – 65 %). Th e weather conditions caused forest and peat bog fi res over an area about 350 hectares in the Moscow region. During that time, and especially at the end of July and beginning of September, the vis- ibility was restricted to less than 2 km.

Th e protracted fi res, industrial emissions and vehicle exhausts resulted in high concentration of toxic air pollutants in the ambient air of Moscow. For many days a haze and a smell of burning were present.

During the smog Moscow medical authorities exerted eff orts to help the people overcome by the envi- ronmental conditions. Th e number of serviced medical emergency calls during August and September increased by 10 %. Moscow TV and radio reported instructions on how people should behave to avoid damage to their health.

During the smog period many eff orts were made to reduce the amount of pollution in the ambient air of Moscow. Th e main task, of course, was fi rst to prevent the peat bog and forest fi res from spreading, and then to extinguish them. It was very diffi cult task to perform mainly because of the water shortage in the peat bog areas. Th e spokespersons of the Anti-fi re State Services explained at that time they extinguished up to 40 fi res each day. However, at the same time many new fi res sprang up. Th e struggle with the fi res was stopped only at the end of September. Th ese eff orts played an important role in the reduction of air pollution during Summer 2002.

In addition, the temporal reduction of emissions from the most hazardous industrial enterprises in Moscow upon the request of Moscow authorities, helped to improve the ambient air condition during the most crucial period of the event.

Due to the lack of appropriate and timely data on health outcomes of the smog at that time, the Minis- try of Health and the Moscow Government asked the Research Institute of Human Ecology and Environ- mental Hygiene together with the Moscow Sanitary-and-Epidemiological Centre to quickly evaluate pos- sible adverse health eff ects caused by the smog. Th e information was needed for further decision-making in an eff ort to overcome the consequences of the smog.

Health Hazards

Air pollutants together with the increased ambient temperature are the basic factors determining health hazards of such smog. In general, a list of chemical substances that are emitted into the air during this kind of weather event include total suspended particulates (TSP), specifi cally fi ne fractions of TSP – particulate matter with the eff ective diameter of particles up to 10 microns (PM10), and particulate matter with the eff ective diameter of particles up to 2.5 microns (РМ2.5), ozone, sulphur dioxide, nitrogen dioxide, car- bon dioxide, benzene, formaldehyde, polychlorinated dioxins and benzofurans and some other dangerous organic chemical substances including carcinogens (Hurley and Donnan 1999).

In this study PM10, PM2.5, ozone, carbon monoxide, sulphur dioxide and nitrogen dioxide were cho- sen as pollutants of concern because of their high concentration and, consequently, great aff ect to human health. Th e main health hazards caused by the studied pollutants are described below (Hurley and Don- nan 1999, Vedal 1996).

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257 Moscow Smog of Summer 2002. Evaluation of Adverse Health Eﬀ ects 25

Particulate matter (PM10 and PM2.5)

Population groups that are most sensitive to particulate matter exposure include asthmatics, the elderly (over 65 years old), children, people with cardiovascular (CVD) and respiratory (RD) diseases, and ex- pectant mothers. Air pollution by PM2.5 accounts for an excessive increase in total, CVD and RD mortal- ity especially in the elderly. Children and adults are subjected to excessive chronic bronchitises and asth- mas. Usually at the same time an increase in the number of doctor visits, hospitalisation and emergency calls is observed. Exacerbation of chronic conditions (asthma), respiratory obstruction, and myocardial ischemia are among the causes of visits and emergency calls. Th e causes for the increased hospitalisation are myocardial infarctions (MI) and cardiac rate disturbances.

People with chronic asthma and angina need to increase the dose of medicine to withstand the disease.

Very oft en the adverse eff ects of PM pollution reveal themselves by an increase in the respiratory symptom frequency rate (cough, angina pain), and in the number of days of partial or total disability due to morbid- ity and the days of restricted activities (decrease in capacity for work and indispositions).

Ozone

Usually high ozone concentrations are registered in summer time, especially in hot sunny aft ernoons.

Air pollutants from industrial enterprises, vehicle exhausts and forest and peat bog fi res increase ozone formation. Th e most vulnerable population groups to ozone are asthmatics, children and the elderly, peo- ple suff ering from respiratory diseases, people performing physical work outdoors and smokers. Typi- cal symptoms of ozone poisoning are irritation of the eyes and respiratory tract, bronchospasm, general intoxication (headache, undue fatigue, chest pain and heavy breathing). If caused by relatively low ozone concentrations the symptoms disappear between 5 and 7 days aft er the exposure termination.

Air pollution by ozone accounts for excessive increase in total, CVD and RD mortality.

Carbon monoxide

Carbon monoxide (CO) is the result of incomplete combustion of fl ammable substances. Th e gas from the ambient air is capable of reacting with the haemoglobin in blood producing carboxyhemoglobin (CoHb).

A concentration of 3 % or less of CO in human blood produces no adverse eff ects, while smokers usually have a concentration of between 3 % and 8 % CoHb. A concentration of between 2 % and 10 % CO in human foetus blood causes low birth weight, whereas a concentration of between 10 % and 20 % leads to the development of the clinical signs of poisoning – headache, eyesight degradation and heavy breathing.

Death occurs where a concentration reaches between 50 % and 60 % CoHb. Th e usual CoHb concentra- tion level for urban population is between 0.8 % and 1.9 % for non-smokers and 3.6 % for smokers. Air pollution by CO accounts for excessive increase in total mortality and acute MI.

Sulphur dioxide

Increase of sulphur dioxide concentration during the smog period causes great concern. Th is gas is the

product of the wood and peat burning and at the same time is emitted in large quantities by industrial en-

terprises and vehicles. Adverse eff ects of sulphur dioxide is similar to that of TSP and nitrogen dioxide.

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258 25 Moscow Smog of Summer 2002. Evaluation of Adverse Health Eﬀ ects

Nitrogen dioxide

Nitrogen dioxide (NO2) is produced in any combustion process. Th e main sources of NO2 in big cities are usually industrial enterprises and powerplants. Young children (5 years old and younger), asthmatics and elderly people, with RD and CVD are the most sensitive to NO2. NO2 aff ects the immune system and increases the sensitivity of humans to pathogens and viruses.

Air pollution data

In order to evaluate the possible adverse health eff ects of the selected air pollutants during the smog period their concentrations were obtained and analysed.

Th e concentrations of TSP, PM2.5, NO2, sulphur dioxide, CO, and ozone were received from the Mos- cow Centre for Hydrometeorology and Environment Monitoring and the Public Environmental Enter- prise “Mosecomonitoring”.

In contrast to other studied smogs, the ambient air concentrations of sulphur dioxide in Moscow dur- ing the smog period were relatively low (the daily mean for the smog period was at the usual level for that time of year). For this reason sulphur dioxide was excluded from further analysis.

For all pollutants the mean daily concentrations for each day of the monitoring during the smog pe- riod were calculated ( > Fig. 1 – 4). Unfortunately, the obtained data refers to diff erent time-periods dur- ing the smog for diff erent pollutants. Th is fact must be considered while studying the presented data. Each fi gure shows also the pollutant‘s upper limit of a harmless concentration, so-called reference concentra- tion (RFC)1. Th is helps to better understand the real magnitude of the concentration values. As a rule the Russian maximum allowable concentration were taken as RFC values. RFC for PM2.5 was taken from the US EPA National Ambient Air Quality Standards (NAAQS).

Th e fi gures show a dramatic rise in PM2.5 mean daily concentration (the mean value for the ana- lysed smog period was 0.20 mg/m3 compared to the mean yearly of 0.07 mg/m3). Concentration of NO2 increased from 0.07 to 0.11 mg/m3, and those of ozone increased from 0.034 to 0.042 mg/m3. Th e mean concentration of CO ( > Fig. 2) remained at the level of the yearly mean (2.8 mg/m3), but at the end of July and the beginning of September increased concentrations were observed, the local maximum of 5.8 mg/

m3 being reached on the 5th of September.

Evaluation of the Adverse Health Effects

Th e health risk assessment methodology was used to evaluate the main adverse health eff ects. Specifi cally, concentration-response functions for selected air pollutants were used to calculate the number of cases for each eff ect.

A computer program “EpidCalc”, developed in the Institute of Human Ecology and Environmental Hygiene, was used for the purpose of evaluation. Th e program’s database contained complete reference information on the 25 most hazardous air pollutants that could be found in the ambient air of cities and

1

Reference doses (RFD) and concentrations (RFC) are estimates of the pollutant daily exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of adverse effects over a lifetime. Regulatory agencies in many countries calculate (and publish) reference doses or concentrations for non-carcinogens. In the Russian Federation the Ministry of Health has established the national RFCs – MACs (maximum allowable concentrations) for a large list of adverse air pollutants, but not for all pollutants. They have not defined PM2.5 national RFC yet, that is why the NAAQS (USA EPA) RFC is used in this study. The measurements were made by the Moscow Centre for Hydrometeorology and Environment Monitoring and by the Public Environmental Enterprise “Mosecomonitoring”.

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259 Moscow Smog of Summer 2002. Evaluation of Adverse Health Eﬀ ects 25

⊡ Fig. 1

Mean daily PM2.5 concentrations for a period of time during the smog.

⊡ Fig. 2

Mean daily carbon monoxide (CO) concentrations for a period of time during the smog.

⊡ Fig. 3

Mean daily nitrogen dioxide (NO₂) concentrations for a period of time during the smog.

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260 25 Moscow Smog of Summer 2002. Evaluation of Adverse Health Eﬀ ects

towns and enabled calculation of 70 diff erent exposure outcomes. Th e program used a mean daily con- centration value as the input for a concentration-eff ect function to calculate the daily number of cases associated with an outcome. Th en the cumulative eff ect was calculated by adding up all the daily counts for the time-period under consideration. Th e calculations were based upon concentration-response func- tions referenced in WHO (1999, 2000), U.S. Environmental Protection Agency (1999). Th e same approach is employed, for example, in the soft ware tool AirQ developed by WHO and ECEH in order to facilitate European-wide health impact assessments.

In order to compare the impact of each pollutant on people’s health, a ten-day period during the smog from August 30th through to September 8th was chosen. Th e pollutant concentration data for all pollut- ants was available for that period. Th e Moscow health and population statistics for year 2000 were used in calculations if it was required.

> Table 1 presents the number of cases connected with the eff ects that may be caused by the residents’

exposure to the selected pollutants during the ten-day period.

⊡ Tab. 1

The evaluated adverse health effects, caused by selected air pollutants for a ten-day period during the smog of Summer 2002 in Moscow.

Adverse effect Number of cases

Carbon monoxide

Total mortality 11,5

Acute MI 2,1

Ozone

Total mortality 11,2

CVD mortality 5,0

Respiratory mortality 0,8

Hospitalisation with respiratory disease 2,8 Nitrogen dioxide

Total mortality 12,6

CVD mortality 5,4

Acute MI 2,7

Hospitalisation with respiratory disease 2,0

⊡ Fig. 4

Mean daily ozone concentrations for a period of time during the smog.

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261 Moscow Smog of Summer 2002. Evaluation of Adverse Health Eﬀ ects 25

Adverse effect Number of cases

PM2.5

Total mortality 98,7

**PM10 (recalculated from PM2.5 concentrations*)**

CVD mortality 56,4

Respiratory mortality 4,6

MI, myocardial infarctions; CVD, Cardiovascular diseases; PM, particulate matter with indicated diameter

* It was assumed that PM

10

= 0.55*TSP and PM

2.5

= 0.33*TSP.

Table 1 evidently shows that exposure to PM2.5 and PM10 probably was the most hazardous compared with exposures to the other studied pollutants. 98.7 predicted cases of total mortality caused by PM2.5 compared to 11.5 cases by CO; 11.2 cases caused by ozone and 12.6 cases caused by NO2. PM10 is also one of the main factors of the health damage (56.4 cases of CVD mortality compared to 5.0 caused by ozone and 5.4 by NO2).

Additional analysis showed that the maximum number of daily total mortality cases from the expo- sure to PM2.5 and PM10 may have been 32 and 25.7 (on 18/09/2002) respectively, 3.5 cases from exposure to NO2 (on 04/09/2002) and 1.8 cases from CO exposure (on 05/09/2002). Th is confi rms the signifi cance of PM2.5 and PM10 among studied pollutants.

Conclusions

Th e preliminary results obtained from the adverse health eff ects evaluation were used for a number of activities:

• In preparation of the informative letters to the Sanitary-and-Epidemiological Department of the Min- istry of Health and Moscow Government.

• In working out the list of studies for deeper analysis of the adverse health eff ects of the Summer 2002 smog.

• In the development of a proposal to the Moscow Government for improvement of the air monitoring, access to the medical statistics and implementation of warning conditions for a weather extreme event and appropriate alert procedures in order to provide eff ective interaction among the diff erent services of the authority in case of extreme eff ects in the future.

Studies are now being carried out on more precise characterisation of the ambient air pollution for the smog period and on analysis of real statistics of the adverse health eff ects. Unfortunately, due to the ab- sence of daily statistics in computer form (Moscow hospitals and policlinics are obliged to give monthly summary reports only) and the lack of funds to pay for the extraction of the data from the hospitals records, these studies are being delayed. Th ese problems (as well as others) forced the authorities to ask health risk methodology experts to evaluate the smog adverse health eff ects.

Th e studies will enable more reliable conclusions to be made about the magnitude of the health dam- age caused by the forest and peat bog fi res in the summer period of 2002 and to improve the adverse health eff ect evaluation methodology.

⊡ Tab. 1 (Continued)

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262 25 Moscow Smog of Summer 2002. Evaluation of Adverse Health Eﬀ ects

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