Relation Between Temperature And Mortality In Shanghai Biology Essay

Although the relation between temperature and mortality has been studied for many decennaries public wellness menace due to elevated temperature did non truly go recognized as an issue with considerable magnitude until the late eightiess. To day of the month, there is consistent grounds that air pollution has short-run effects on mortality.

Increased atmospheric concentration of nursery gases, of which CO2 is the most of import, may increase the mean temperature by 2-5.5 grades ( Celsius ) by the terminal of this century ( IPCC, 2001 ) . Behind this mean, with alleged “ urban heat island consequence ” , people populating in urban country are particularly vulnerable, non merely because urban countries typically have higher heat indexes ( combinations of temperature and humidness ) , but besides because by and large the urban population is more elderly which of course deteriorate the capableness of people to make accommodation with un-nice conditions ( Basu et al. 2002 ) .

A close reading of the IPCC 2007 study indicates that clime alteration will impact all states and in general undermine the sustainability of the supports of 1000000s, but the worst impact will fall on developing states, partially because of their geographical location, partially because of weak get bying capacities, and partially due to more vulnerable societal, institutional and physical substructure. This decision could indirectly be supported by the fact that to day of the month at that place has been really small epidemiological research on the wellness impact of thermic emphasis on urban population of developing states ( Gouveia et al. 2003 ) .

In this paper, we apply a clip series patterning model to stipulate and gauge a theoretical account for the relationship between temperature and mortality in the metropolis of Shanghaii??a warm temperate zone metropolis in the Asian Pacific rim, conditional on long-run tendencies in demographic features, societal & amp ; economical development, seasonal consequence, and environmental status.

Equally far as we know, the analysis in this paper is the first effort to set about a long term temperature-air pollution-mortality relationship survey in China. Even in Asian Pacific part, the survey based on day-to-day mortality count is still rather rare. One in Beijing, China based on 1-year day-to-day informations, two in Australia, two in Korea and one in Hong Kong.

The day-to-day meteoric informations in Shanghai for 1956-2001 is extracted from the dataset of Daily Surface Climate Normal of International Exchanging Stations of China prepared by China Meteorological Administration. The day-to-day decease counts for all non-accidental causes ( International Classification of Diseases, Revision 9 & lt ; 800 ) in 14 sampled old ages ( 1956, 1961, 1963, 1966, 1968, 1971, 1976, 1981, 1986, 1990, 1991, 1996, 2000 and 2001 ) in 7 sampled territories ( Changni, Hongkou, Luwang, Nanshi, Xuhui, Yangpu and Zhabei ) in the metropolis of Shanghai is extracted from the dataset digitalized by Vita Statistics Department, Shanghai Center of Disease Control and Prevention. The day-to-day air pollution informations for 1998-2006 is straight from the web site of Shanghai Environmental Protection Bureau ( hypertext transfer protocol: //www.sepb.gov.cn/ ) .

The balance of the paper is structured as follows. In subdivision 2, the 45 old ages day-to-day temperature informations is intensively analyzed with the purpose that we try to sum up the earnestness of the clime alteration menace. Section 3 some drumhead statistics of mortality result, air pollution degrees, and meteoric steps by season. In subdivision 4, the General Additive Models ( GAMs ) is presented and we present the estimations consequences. Exposure-response relationships sing with three cardinal air pollutants in warm and cold seasons were besides intensively examined utilizing GAMs patterning. In subdivision 5 comes the decision.

2. TEMPERATURE CHANGING IN SHANGHAI

The day-to-day meteoric parametric quantities include day-to-day mean, upper limit and minimal temperature, comparative humidness, barometric force per unit area and air current velocity. We consider these as meteoric placeholder stand foring whole Shanghai temperature degree.

The analytical attack followed standard clip series methods that have been developed for fiscal econometrics.

Suppose the clip series for temperature can be decomposed into a macroscopic constituent and a microscopic constituent. The macroscopic constituent is described through a tendency and seasonality, whereas the microscopic constituent is picked up by a noise. We assume the tendency, the seasonality and the noise take an linear signifier.

( 1 )

whereis the temperature in period, is the clip tendency in period, andis the noise in period.

First, we estimate the tendency portion by a moving mean filter over a complete rhythm so that the consequence of the seasonality is averaged out. This method is approved by Ngai Hang Chan ( 2002 ) . In our informations, we set the length of the filter at 6. Then a 13 point traveling norm is used to stand for one twelvemonth length consequence. That is

( 2 )

where.

After gauging, filter the tendency out from the information. Next we apply a moving mean method ( Brockwell and Davis, 1991 ) to gauge the seasonal portion from the residuary. We assume that each month has a seasonal consequence, that is, and satisfies.

( 3 )

Then, gives us the deseasonalized clip series that include the tendency and noise merely.

To acquire the pure noise, we re-estimate the trendfrom the deseasonalized clip seriesby using the same filter as in expression ( 2 ) .gives us the pure remainder.

With the theoretical account set up above, we estimate the tendency, seasonality and noise in clip series for temperature to prove whether the temperature has the intendancy ( combination of planetary heating and the local urban heat island consequence ) to increase in Shanghai in the past half century and more significantly how much the addition is.

In figure 1, the top secret plan is for the natural temperature informations from twelvemonth 1956-2001. The 2nd secret plan is the clip series after deseasonalized. In which we suspect that it has an increasing inclination with the clip. We examine this inclination further in the following paragraph. The 3rd secret plan gives us the seasonal rhythm that is estimated by traveling mean method. The last secret plan is the remainders after deseasonalized and detrending, from which, we could acknowledge a decreasing discrepancy associated with clip. We come to this inclination subsequently excessively.

Figure 1 Deseasonalized and detrend clip series for temperature in Shanghai

Based on the increasing inclination in the 2nd figure in Figure 1, the deseasonalized clip series is regressed on the clip. Figure 2 shows the fitted arrested development line and table 1 gives the estimations. From 1956 to 2001, the temperature increases about 1 Celsius grade in the additive anticipation. Coefficient for timeis positive and important at 1 % degree.

Figure 2 Time tendency fitted for deseasonalized temperature informations in Shanghai

Table 1 Time tendency trial for deseasonalized informations

Estimate

Standard Error

Intercept

15.22

0.10

Coefficient for

2.65e-03

3.05e-04

Following, allow us analyze the decreasing inclination in discrepancy of residuary. We start to analyse this inclination from three dimensions. The first dimension is the difference between utmost high temperature and utmost low temperature for each twelvemonth. The 2nd is the utmost high temperature and the 3rd is utmost low temperature. This first figure in Figure 3 shows that the difference between highest and lowest temperature becomes smaller in the recent yesteryear. The following two figures show that both the utmost high and utmost low temperature in each twelvemonth tends to increase and the utmost low temperature additions at a higher velocity, which gives the reply to why the discrepancy of the remainder in recent past twelvemonth lessenings.

Figure 3 Analysis for temperature altering from 1956 to 2001

All these inclinations in figure 3 are supported by arrested development consequences in table 2. All estimations in table 2 have the expected marks and important at 1 % degree.

Table 2 Time tendency trial for temperature difference, utmost high and utmost low

Model 1, Temperature difference between Extreme high and Extreme low as Dependant variable

Estimate

Standard Error

Intercept

35.24

0.53

Coefficient for

-0.04

0.019

Model 2, Extreme high temperature as Dependant variable

Estimate

Standard Error

Intercept

30.96

0.26

Coefficient for

0.03

0.01

Model 3, Extreme low temperature as Dependant variable

Estimate

Standard Error

Intercept

-4.28

0.45

Coefficient for

0.07

0.02

From above analysis, we get the grounds that the temperature increased in the past several decennaries which supports the anticipation every bit good as the intuitive societal feeling of the conditions is acquiring warming. Furthermore, the annual utmost high and utmost low temperature tends to increase and particularly the utmost low temperature additions at a higher velocity. This inclination has of import effects on the mortality non merely in the sense that they are efficient in advancing mortality, but besides in the sense that unusual high temperature and unusual low temperature have different effects on specific cause mortality which lead to different public wellness intercession schemes. Finally, the diminishing difference between utmost high and low temperature tells us a new conditions form comes with the characteristic of ill-defined seasonality.

3. SUMMARY STATISTICS OF MORTALITY OUTCOME, AIR POLLUTION LEVELS, AND METEOROLOGICAL MEASURES BY SEASON

All pollutant degrees are unacceptable high in Shanghai. Although mentioning with Chinese criterion, Shanghai is regarded as advanced metropolis in environmental protection comparing with Beijing, Guangzhou, and other large metropoliss. From the period of 1998 to 2007 ( 3149 yearss ) , for PM10 ( 24-hr ) is about 29.1 % yearss, for NO2 ( 24-hr ) is about 50 % yearss, and for SO2 ( 24-hr ) is about 10 % yearss in Shanghai have reached the World Health Organization ( WHO ) air quality guidelines ( www.who.int ) . The state of affairss become farther worse in cool season, the proportions decrease to 23.9 % , 39.2 % and 6.8 % severally. If we consider the proportion of yearss with all three contaminations ( PM10, NO2, SO2 ) making WHO guidelines, the figure is approximately 5 % , and if the day-to-day informations of O3 were public available, with inclusion of O3, it is rather plausible that the proportion will meet to zero.

Table 3 Guideline values and the cardinal wellness effects

Contaminant

Guideline values ( Aµg/m3 )

Key wellness effects

( www.mfe.govt.nz )

Value Averaging clip

PM10

50 24-hour

20 Annual

Mortality, morbidity, hospitalization, work-affected yearss, increased usage of medicine.

NO2

200 1-hour

40 Annual

Apparent part to morbidity and mortality, particularly in susceptible subgroups, including immature kids, asthmatics and those with chronic inflammatory airway disease.

SO2

20 24-hour

500 1-minute

Daily mortality, hospital admittances and exigency room attendings for respiratory and cardiovascular disease, increases in respiratory symptoms and lessenings in lung map.

O3

100 8-hour

Increased day-to-day mortality, respiratory and cardiovascular disease ; decreases in lung map ; additions in hospitalizations, and in respiratory unwellnesss such as cough, emotionlessness and wheeze.

Table 4 Drumhead statistics of mortality, air pollution, and meteoric measuring

No.day

Mean

South dakota

Minute

Median

Soap

Mortality counts

( *for twelvemonth 1996, 2000, 2001 )

Nonaccident ( ICD: & lt ; 800 )

Warm

549

83.68

.500

57

83.00

143

Cool

548

108.25

.787

59

107.50

161

Air pollution concentrations ( I?g/m3 ) i??*from 1998.5.28 to 2007.1.15i?‰

NO2 ( 24-hr )

Warm

1345

43.96

0.84

7

34

221

Cool

1804

61.12

1.01

15

46

315

SO2 ( 24-hr )

Warm

1345

37.34

0.41

5

36

77

Cool

1804

47.02

.44

8

47

115

PM10 ( 24-hr )

Warm

1345

58.19

0.61

8

55

155

Cool

1804

74.51

0.95

8

66

434

Meteorologic measuring

( *from 1956-2001 )

Daily Average Temperature ( 0.1a„? )

Warm

8339

234.19

.49

75

234

342

Cool

8464

84.76

.57

-69

82

252

Daily Average Humidity ( % )

Warm

8339

80.01

.10

39

81

98

Cool

8464

75.35

.13

34

76

100

Note: Warm season covers the period from October to March ; cold season covers the period from April to September.

For the past 20 old ages, Shanghai has experienced profound industrial construction accommodations to transform a manufactory-based economic system to a service-based one which has important positive effects on air quality, particularly, helps a batch with the lessening of sulfur content fuel ingestion. The job is like SO2, PM10 are some sort authoritative trans-boundary pollutants, without efficient regional environmental coordination, Shanghai ‘s attempt could be greatly offset by the free-rider behaviour from the environing metropoliss. Meanwhile as other Asiatic metropolitan metropoliss, for the past 20 old ages, Shanghai besides has experienced unprecedented traffic roar due to strong demand for cars from family. Therefore for the contaminations related with cars, it is rather likely NO2 and O3 are still on the path of robust increasing, or at least non traveling to diminish as easy and rapidly as PM10 and SO2 do, although both Chinese cardinal authorities and local Shanghai authorities has committed with the decrease of pollution emanation.

The analytical attack for air pollution tendency followed the same times series methods that have been deployed for temperature surveies in the former portion.

In figure 4, the upper three secret plans are for the natural air pollution informations from twelvemonth 1998-2007, the lower three secret plans are the clip series air pollution informations after deseasonalized. In which we suspect that PM10 takes quadratic signifier in clip and had achieved its extremum value in 2003 and presently is on the phase of diminishing way ; SO2 takes three-dimensional signifier in clip and has ill-defined sigh in the long term ; for NO2, we could acknowledge a important decreasing tendency which converges to some changeless degree at least in short term.

Figure 4 Original & A ; deseasonalized clip series informations for air pollution degree in Shanghai

We use a set of additive arrested development theoretical accounts to suit the deseasonalized clip series pollution informations based on the false theoretical account specifications we observe from the figure 4.

Table 5 gives the estimations for three fitted arrested development. All coefficients for timeare positive and important.

Figure 5 Time tendency fitted for deseasonalized pollution informations in Shanghai

Table 5 Time tendency trial for three chief air pollution contaminations in Shanghai

Model 1, Daily PM10 value as Dependant variable

Estimate

Standard Error

Intercept

43.05

3.68

Coefficient for

1.24

0.17

Coefficient for2

-0.01

0.00

Model 2, Daily SO2 value as Dependant variable

Estimate

Standard Error

Intercept

45.01

3.06

Coefficient for

-0.68

0.27

Coefficient for2

0.18

0.01

Coefficient for3

-0.0001

0.00004

Model 3, Daily NO2 value as Dependant variable

Estimate

Standard Error

Intercept

39.92

2.27

Coefficient for

234.45

27.82

With the statistics theoretical accounts above, we could reason with caution that Shanghai is now on the passage phase germinating from a most contaminated metropolis to a clean one, although some advancement looks rather promising, while some a small spot weak. Comparing other Asiatic large metropoliss, like Hongkong ( Wong et al. 2001 ) and Seoul ( Lee et al. 1999 ) , Shanghai is about 10 old ages left behind in environmental protection. We start from theoretical account 1 in table 5, as we expected, from 2003 the incline of PM10 way became negative with mean yearly decrease rate 5Aµg/m3 which means with the given tendency by the terminal of 2009 the day-to-day expected value of PM10 in Shanghai would make WHO counsel. From theoretical account 2 in table 5, there is no clear mark how SO2 will be traveling on particularly in the long term. Since SO2 chiefly has inauspicious consequence on respiratory and cardiovascular disease, combing the population ripening, we would give more elaborate analysis for this combination consequence in subdivision 4. Model 3 in table 5 shows a heartening tendency NO2 is traveling to the intercept value 39.92 which is precisely the value recommended by WHO.

4. RELATIONSHIP BETWEEN TEMPERATURE, AIR POLLUTION AND MORTALITY IN SHANGHAI

The decease counts per twenty-four hours were matched to the daily-averaged degrees of temperature, humidness, PM10, SO2, and NO2 on the same twenty-four hours.

We used a generalised linear theoretical accounts ( GAMs ) with nonparametric smoothing maps ( splines ) to depict nonlinear dealingss between temperature, air pollution and mortality ( TM ) in Shanghai. We specify a GAMs particularly designed to take into history long-run tendencies in demographic features, societal & A ; economic development and seasonal consequence, likewise to the analytical model in Curriero ( 2002 ) , every bit good as everyday temperature and air pollution variables. We farther estimate the TM by epoch, by specific communities to see the fluctuation in clip and in the inside-city.

In order to prove whether there are independent effects of a individual pollutant to account for a wellness result in the metropolis of Shanghai, we once more used a Poisson arrested development with day-to-day mortality counts as the dependant variable. It is besides extremely interesting to prove whether there are thresholds and additive ( non-linear ) relationships of TM. Since a similar research has been done in Hong Kong ( Wong et al. 2001 ) ; therefore it is possible we could make some comparing analysis.

It is widely believed that the local air pollution policy should be based on local exposure-response relationship. In this respects, this research do important part to the apprehension of the wellness effects of air pollutants in the metropolis of Shanghai.

The basic thought behind the GAMS is the map of TM is smooth but non needfully linear which has self grounds advantage in its flexibleness and efficiency in explicating the nonlinear relation between mortality and temperature and other independent variables, like pollution.

We consider utilizing calendar clip to function as a catch-all variable to stand for the unseen events like long-run population construction alteration, betterment in single nutrition, entree to air-conditioner, tendencies in public wellness pattern, etc.

See temperature, humidness and air-pressure have non merely immediate consequence on mortality but besides lagged 1s. We included same-day temperature/ humidity/ air force per unit area, , and adjusted lagged conditions variables including predating 3 yearss mean temperature/humidity/air force per unit area, ,and adjusted predating 4-10 yearss mean temperature/humidity/air force per unit area, , ( the slowdown period have an exponentially increasing size. ) . The ground we use adjusted conditions variables instead than original conditions variables is to avoid the serious multi-collinearity between the original conditions variables. Assume the lagged conditions and the unlagged conditions variables satisfy the undermentioned relation.

( 4 )

whereis the lagged conditions variable, is a vector of unlagged conditions variable, andis a white noise. For case, see the temperature, When, , i?›whereas wheni??the adjusted weather variable is.

The formal GAMs theoretical account has the signifier:

Log expected mortalityt = ( 5 )

Where represents a smooth comparative hazard map with grade of freedom, and represents calendar clip. Here we consider every twelvemonth has 2 df ( we besides try norm of 4, 6 and 12 df severally, per twelvemonth, but the consequences are non interesting ) , for warm/cold seasons to set the seasonal confounders.

Arrested development theoretical accounts were fitted with the MGCV bundle in R.

Figure 6 studies how TM maps evolve steadily with clip in the metropolis of Shanghai.

Figure 7 reports the important fluctuation of TM map in different community in the metropolis of Shanghai.

Figure 6 TM Relative Risk Function for Shanghai, 1956-2001.

Figure 7 TM log hazard map for Yangpu, Changni and Xuhui

We extend the GAMs mold ( 5 ) to analyse the relationship between the day-to-day decease count and the day-to-day agencies of concentrations of PM10, NO2 and SO2. The formal drawn-out GAMs theoretical account has the signifier:

Log expected mortalityt =

( 6 )

The chief consequences of theoretical account ( 6 ) are summarized in figure 8, figure 9 and figure 10.

Figure 8 log hazard map for PM10 in Shanghai ( 2000-2001 )

Figure 9 log hazard map for day-to-day NO2 in Shanghai ( 2000-2001 )

Figure 10 log hazard map for day-to-day SO2 in Shanghai ( 2000-2001 )

Next we try to prove whether there are independent effects of a individual pollutant to account for a wellness result in the metropolis of Shanghai. Follow the criterion scheme ( Wong et al. 2001 ) , we start from obtaining a nucleus theoretical account for each of the mortality outcomes ( noaccident decease, cardiovascular decease, and Respiratory decease ) for all ages, nonparametric smoothing by agencies of loess map footings for tendency on seasonality ( warm season and cold season ) , temperature, and humidness were fitted as independent variables. To execute the graded analyses, we foremost obtained expected mortality counts from the nucleus theoretical account for all seasons. Poisson arrested development for the mortality outcomes was so fitted on pollutant concentrations to obtain the log comparative hazard estimatewith offset on individually for warm ( April – September ) and cold seasons ( Other months ) . Offset is a calculation process to treatas a mention value and does non continue to gauge a parametric quantity for it in the Poisson arrested development. Exposure – response curves in warm and cold seasons were once more examined utilizing Generalized Additive Modeling model. That is, the Poisson arrested development is transformed into ( whereis the smoothing map that are represented utilizing penalized arrested development splines with smoothing parametric quantities selected by Generalized Cross Validation. And the figures below are the relationship between pollutants concentrationsand the estimated log hazard of mortality.

The figure 11, figure 12 and figure 13 show the seasonal exposure-response relationship for each pollutant for the three chief mortality result.

Figure11 Smoothed secret plans of SO2 against mortality hazard in log graduated table ( deviated from overall mean )

Figure 12 Smoothed secret plans of NO2 against mortality hazard in log graduated table ( deviated from overall mean )

Figure 13 Smoothed secret plans of PM10 against mortality hazard in log graduated table ( deviated from overall mean )

5. RESULTS AND DISCUSSION

5.1 The fluctuation of V-shaped TM with clip

Based on the half-century day-to-day mortality informations in the metropolis of Shanghai, it is rather clear that the consequence of temperature on mortality varied with clip, even though the general V-shaped relation supports constant in the sense that mortality hazard is positively correlated with both the coldest temperatures and the hottest temperatures. The most dramatic thing is the threshold temperature ( the temperature matching with the lowest mortality hazard ) , which is around 23 Celsius, besides keeps changeless.

Even though from 1990s the home/office air conditioner is widely available in the metropolis of Shanghai and rapidly became impregnation by the terminal of 1990s. We could see the TM ‘s fluctuation in clip in two respects. First from 1970s, the original V-shaped temperature-mortality dealingss had easy changed into a reversed-J-shaped 1 with a flatting tail at warmer temperature, connoting small addition in mortality hazard for the hottest yearss. Second as clip goes on, the TM ‘s inclines ( both the inclines in the coldest yearss and in the hottest yearss ) significantly decrease with more advancement in the coldest yearss from 1970s to 1990s. We could detect more disparity between the TM 1971-1986 curve and the TM 1990-2001curve in the cold season than in the warm season. Shanghainese benefit a batch from the debut of air conditioner, the addition of personal consciousness about the inauspicious wellness consequence from the cold conditions, the betterment of environment, etc, possibly the tendency of consistent acquiring warming besides should be included, even though detailed informations on these events were non available, meanwhile these advancement besides happened at the same time, hence technically it is impossible to quantitatively distinguish these effects ‘ ain part.

5.2 The fluctuation of TM with communities

We use three territories, Xuhui ( XH represents rich and advanced communities in Shanghai ) , Changni ( CN represents mean communities in Shanghai ) , and Yangpu ( YP represents less developed communities in Shanghai ) to demo the TM ‘s fluctuation among communities. We originally assume that the curve of TM map in advanced communities should be more level than that of less advanced communities. Some empirical findings are consistent with our original hypothesis, but some do non. In cold season, the richer communities seem to be more experient with seting the coldest temperature than hapless communities which is consistent with our hypothesis ; but in warm season, the poorer communities seem to be more “ clever ” with seting the hottest temperature than rich communities which turn out to be un-consistent with our hypothesis.

Since the information of community specific social-economical degree is non available at current phase, we here merely supply one possible account for this “ mystifier ” which really partially based on the empirical determination from the first secret plan in Figure 7. It is extremely possible that population ripening is much more important gas pedal than other alleged social-economical factors in advancing the mortality hazard in the sense that being younger is more helpful than being rich in seting with un-nice temperature every bit good as air pollution. Xuhui is the most elderly territory in Shanghai and hence people in Xuhui territory have the most likeliness of being old and being delicate comparing with the people in the less elderly territories, Changni and Yangpu. Even though Xuhui is the richest territory in Shanghai and people populating in Xuhui territory by and large are good educated and averagely have the best entree with wellness service, air conditioner, inner heating system and related wellness cognition. Based on the 2nd secret plan in figure 7, it seems the precautious behaviour ( like utilizing air conditioner, better populating infinite, suited vesture, etc ) are more efficient in seting cold conditions in winter season, but less utile in the hottest yearss.

5.3 The fluctuation of mortality pollution map with communities

It is rather confounding with the inconsistent air pollution reaction maps by different territories. The city-pooled pollution index possibly is misdirecting in the sense that the pollution index published by the authorities may non relevant with specific territory ; meanwhile the air pollution degree by territory is non available. Even though we still could stipulate some consistent form based on the secret plans above. For the territories Zhabei and Yangpu, these two territories are traditional Shanghai heavy industry country ; hence Zhabei, Yangpu is tend to hold the highest PM10 degree comparing with the downtown territories, Xuhui, Luwang and Nanshi. From figure 8, Zhabei and Yangpu has the most sensitive reaction map with PM10. Again the age construction extremely matters the reaction map with air pollution with same logic we discussed in former paragraph. Xuhui, Luwang, these most aged affluent territories is the territory most vulnerable.

5.4 The relationship between pollutant concentration and mortality stratified by season

The most dramatic determination was that SO2 had about identical/linear effects on all three mortality results during the cold season. Harmonizing to our limited literature reappraisal, this determination is alone. In summer season, there is no clear exposure-response relationship were observed when SO2 & lt ; 50 ( in Hong Kong, the figure is 30 ) , but there were some additive exposure-response relationship above that concentration for respiratory mortality and noaccident mortality. Unlike Hong Kong, in Shanghai it seems there was no exposure-response relationship between cardiovascular mortality and the concentration of SO2 for warm season.

During the warm season, we observed once more the additive exposure-response relationship for cardiovascular and respiratory mortality for NO2, no exposure-response relationship for noaccident mortality for NO2. During the cold season there were some strong additive and nonlinear positive exposure-response relationships for the three mortality results throughout the concentration degrees. Again there is no threshold for NO2 in exposure-response relationship with three mortality results during cold season.

For PM10, during warm season, there seems bing some threshold 125for cardiovascular mortality. Below this degree, there was no exposure-response relationship. During warm season, there is negative exposure-response relationship for noaccident mortality for PM10, and some really strong additive positive exposure-response relationship for respiratory mortality for PM10. During cold season, there were once more some about additive positive exposure-response relationships for all three results.

At really high concentrations, the hazards of mortality could be reduced perchance because vulnerable topics may hold died before the concentration had reached the maximal degrees. ( Wong et Al. 2001 )

There are important differences in the pollution degree between the cold season and the warm season that could be easy recognized via look intoing the denseness distribution of X-coordinate in the figure 11 to 13, which could partially explicate the important disparity of exposure-response relationships in seasons. Besides table 4 reported the elaborate information about the seasonal fluctuation in pollution degree.

Comparing with the former research determination in Hong Kong, in Hong Kong, in warm season, except for respiratory mortality, no strong effects of particulate pollutants were observed, it is besides reported that Hong Kong ‘s instance is rather alone comparing with other Western metropoliss. This unique may partially due to Hong Kong ‘s typical conditions conditions in the warm season, it is reported heavy rain, rain storm and typhoons important alleviate the existent exposure-response relationships between air pollution and mortality.

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *