Health Risk Assessment
Health effect
• An acute (short-term) health effect is usually
immediate and reversible when exposure to the
pollutant ends. Common acute health effects
include eye irritation, headaches, and nausea.
• A chronic (long-term) health effect frequently
results in lasting, irreversible effects and occurs
only after extended periods of exposure. Some of
the indicators of chronic health effects include
decreased lung capacity, heart disease, cancer,
and even death.
Source: USEPA, APTI 452, Principles and Practices of Air Pollution Control, Ch2
Upper Respiratory System
• Typically, pollutants enter the body as air is
inhaled through the nose or mouth into the
upper respiratory system.
• Prior to reaching the lower respiratory system,
most of the larger particulate matter (>15μm
diameter) is removed from the body by small
nasal hairs or by the mucus membranes that
line the respiratory tract from the nasal cavity
through the nose and throat (Talukder and
Sharma, 1991).
• Smaller pollutant particles (<10 μm diameter)
that escape these defense mechanisms become
trapped in the cilia. The cilia are fine, hair like
structures that line the respiratory system walls
through the bronchioles.
• Particles measuring between ~1 μm to ~0.1 μm
in diameter that escape capture by higher
defense mechanisms eventually settle in the
alveoli where it may take weeks, months, or
even years to expel the particles.
Source: USEPA, APTI 452, Principles and Practices of Air Pollution Control, Ch2
Human Health Effects of Criteria Pollutants
Source: USEPA, APTI 452, Principles and Practices of Air Pollution Control, Ch2
Human Health Effects of Criteria Pollutants
Source: USEPA, APTI 452, Principles and Practices of Air Pollution Control, Ch2
Various pathways of exposure to HAPs
Health Risk Assessment Process
Source: USEPA, APTI 452, Principles and Practices of Air Pollution Control, Ch2
健康風險評估技術規範
健康風險評估作業應包括危害確認、劑量效應評估、暴露量評估及風險
特徵描述等四部分。
(一)危害確認：包括危害性化學物質種類、危害性化學物質之毒性（致
癌性、包括致畸胎性及生殖能力受損之生殖毒性、生長發育毒性、致突
變性、系統毒性）、危害性化學物質釋放源、危害性化學物質釋放途徑、
危害性化學物質釋放量之確認，相關確認內容、方法如附件一。
(二)劑量效應評估：致癌性危害性化學物質應說明其致癌斜率因子，非
致癌性危害性化學物質應說明其參考劑量、基標劑量或參考濃度。相關
評估內容、方法如附件二。
(三)暴露量評估：進行開發活動於營運階段所釋放危害性化學物質經擴
散後，經由各種介質及各種暴露途徑進入影響範圍內居民體內之總暴露
劑量評估，相關評估內容、方法如附件三。
(四)風險特徵描述：依據前三項之結果加以綜合計算推估，開發活動影
響範圍內居民暴露各種危害性化學物質之總致癌及總非致癌風險，總非
致癌風險以危害指標表示不得高於一；總致癌風險高於10-6 時，開發
單位應提出最佳可行風險管理策略，並經本署環境影響評估審查委員會
審查。風險估算應進行不確定性分析，並以九五％上限值為判定基準值。
相關評估內容及方法如附件四。
Hazard Identification
Hazard identification determines whether exposure to a substance
causes an adverse health effect and the nature of the effect. Once that
determined, hazard identification is also concerned with the pattern
of health effects and their severity. For example. if a pregnant woman
is exposed to a particular chemical. Can it cause birth defects?
Data for the major types of information
used in hazard identification come from:
• Epidemiological studies
• Controlled human experiments
• Animal studies
• In vitro studies
APTI course 400: Introduction to risk assessment / risk management for hazardous air pollutants.
Epidemiological studies: Epidemiology is the study of the
occurrence and distribution of a disease or physiological
condition in human populations and of the factors that
influence this distribution. Epidemiological studies don't
require animal-to-human extrapolation and are conducted
under real exposure conditions with a wide range of subjects.
Controlled human experiments: As with epidemiological
studies, extrapolation from animals to humans is unnecessary.
In addition, it's possible to control such factors as the length of
exposure and the concentration of the exposure. Experiments
on humans are both expensive and are subject to legal
requirements as well as independent review committees. For
those reasons, most of the information on the toxic effects of
chemicals comes from experiments with animal models.
APTI course 400: Introduction to risk assessment / risk management for hazardous air pollutants.
Animal studies: It is important to choose an animal for your study
that has characteristics and genetics similar to humans. Data
comes from animal studies must be extrapolated to humans.
In vitro studies : In cases in which there
are no human data or data from
toxicological animal studies, in vitro
(outside the living organism) genotoxic
studies might be used to assess the
potential for damage in the whole"
organism. Genotoxic means "able to
interact with and damage the genetic
material of the cell," often causing a
mutation.
APTI course 400: Introduction to risk assessment / risk management for hazardous air pollutants.
進行危害確認時，污染物質之毒理資料可由以下四方面取得：
1. 流行病學研究資料：完整的流行病學研究結果可以在污染物質劑量與
健康影響之關聯性中提供令人信服的證據，然而在一般環境中常因污染物
質濃度太低，暴露人數太少，暴露至產生健康影響之潛伏期太長，以及多
重而複雜之暴露狀況等因素，致使要從流行病學研究獲得令人信服的證據
並不容易。
2. 動物實驗資料：在危害確認中最有效的資料通常來自動物實驗分析的
資料。從動物實驗所得的結果推論至人體係毒物學研究之基礎，其精確性
端看實驗所採的生物觀點及使用的藥劑在實驗時產生的健康效應是否合乎
邏輯。
3. 短期試驗（short term test）資料：由於動物實驗需花費龐大之人
力、物力、經費及時間，因此既快速且試驗費用不高之短期試驗如Ames
test，常用來篩選污染物質是否具有潛在之致癌性，或者引導支持動物實
驗及流行病學調查結果，因而非常具有價值。
4. 分子結構的比較：從許多研究及實驗資料顯示致癌能力確實與化學物
質之結構與種類有關，將污染物質之物化特性與已知具致癌性（或健康影
響特性）之物質比對，可以了解此污染物質之潛在的致癌性（或健康影響
特性）。
致癌物質區分方式乃採用世界衛生組織附屬的國際癌症
研究機構（International Agency for Research on
Cancer, IARC）對於人體致癌物質之分類方法，分有:
• 1級：流行病學證據充分，屬確定為致癌物、
• 2A級：流行病學證據有限或不足，但動物實驗證據充分，
屬極有可能為致癌物
• 2B級：流行病學證據有限，且動物實驗證據有限或不足，
屬可能為致癌物
• 3級：流行病學證據不足，且動物實驗證據亦不足，屬無法
歸類為致癌物
• 4級：人類及動物均欠缺致癌性或流行病學證據不足，屬極
可能為非致癌物。
目前1級有111種物質、2A級有66種物質、2B級有285種物
質、3級有505種物質、4級有1種物質。
Dose-Response Assessment
Dose-response assessment takes risk assessment a step further.
Given that the toxic agent in question can cause an adverse
health effect, it becomes important to find out how much of it is
necessary to produce an effect. Dose-response assessment, as
the name implies, deals with the relationship between the dose
of a substance and a measure of harm or injury. Generally, as the
dose increases, so does the severity and intensity of the response,
and the number of people affected.
APTI course 400: Introduction to risk assessment / risk management for hazardous air pollutants.
致癌物質：利用已知劑量效應之流行病學研究，觀察其線性
劑量效應關係圖可得致癌因子 (Slope factor)，
非致癌物質：則因受體多數暴露於低安全劑量或閥值
(Threshold limited value, THV)下，無法直接引用動物實
驗或資料庫調查結果，故由數學模式推估出參考劑量
(Reference dose, RfD)或參考濃度 (Reference
concentration, RfC)。
致癌性：各暴露途徑加總而得慢性每日總暴露劑量 (Chronic
daily intake)，再乘以致癌因子(Slope factor)，求得終生暴
露致癌風險(以下以致癌風險稱之)，環保署致癌風險建議值需
低於10-6。
Risk = Chronic Daily Intake
X Slope Factor
Chronic daily intake：慢性每日總暴露劑量(mg/kg/day)
Slope factor：致癌因子，(mg/kg/day)-1
Source: http://eiareport.epa.gov.tw/eiaweb/DownloadFiles.ashx?shcode=1030051X&sfilename=A09.PDF
非致癌性：比較每日平均暴露劑量 (Average daily dose)與
化學物質參考劑量 (RfD)或參考濃度 (RfC)之間比值，求得非
致癌風險，亦稱危害商數 (Hazard quotient, HQ)，再將各個
化學物質之危害商數加總求得危害指數 (Hazard index,
HI)，臺灣環保署終生暴露非致癌風險(以下以非致癌風險稱
之)建議值需低於1。
HQi = Di / RfDi
HI = ΣHQi
or
HQi = Ci / RfCi
各項意義如下：
HQ :危害商數，亦稱非致癌風險
D,C :劑量或濃度
RfD :參考劑量
RfC :參考濃度
HI :危害指數，亦表示暴露者終生由污染物所造成之非致癌
風險 Source: http://eiareport.epa.gov.tw/eiaweb/DownloadFiles.ashx?shcode=1030051X&sfilename=A09.PDF
（一）參考劑量RfD (reference dose) [mg/kg-day]
（二）參考濃度RfC (reference concentration) [mg/L (水)，mg/m3 (空
氣)，mg/kg(土壤)]
（三）斜率因子 (slope factor) [(mg/kg-day)-1]
（四）危害指數 (Hazard index) [無單位，如果危害指數小於1，預期將不會
造成損害，因為暴露低於會產生不良反應的閾值。如果危害指數大於1，
表示可能會超過此閾值而產生毒性]
（五）致癌風險 (cancer risk) [無單位，一般可接受是介於10-6~10-4]
引起嚴重效應或是前驅效應的最低劑量，也就是“會發生顯著效應的劑量界限
＂，稱為閾值。閾值有以下幾種評估狀況：
未觀察到不良效應之劑量（No-observed-adverse effect level, NOAEL）
可觀察到不良效應之最低劑量（Lowest-observed-adverse effect level,
LOAEL）
在非線性劑量效應評估中進行參考劑量(reference dose, RfD)或參考濃度
(reference concentration, RfC)的推估中，另外要考慮不確定因子
(uncertainty factors, UFs)的存在。所謂UFs指的是在實際推估中利用不同種
類生物(例如動物資料推估人類資料)進行所可能存在的差異性。RfD或RfC可以
下列公式計算：
RfD (mg/kg/day) or RfC (mg/m3/day) = NOAEL (or LOAEL) / UFs
The RfD (expressed in units of mg of substance/kg body weight-day) is
defined as an estimate (with uncertainty spanning perhaps an order of
magnitude) of a daily exposure to the human population (including
sensitive subgroups) that is likely to be without an appreciable risk of
deleterious effects during a lifetime. An RfD can be derived from a noobserved-adverse-effect level (NOAEL), lowest-observed-adverse-effect
level (LOAEL), or benchmark dose, with uncertainty factors generally
applied to reflect limitations of the data used. The inhalation RfC
(expressed in units of mg of substance/m3 air) is analogous to the oral
RfD but provides a continuous inhalation exposure estimate. The
inhalation RfC considers toxic effects for both the respiratory system
(portal of entry) and effects peripheral to the respiratory system
(extrarespiratory or systemic effects). Reference values may also be
derived for acute (≤24 hours), short-term (>24 hours, up to 30 days),
and subchronic (>30 days, up to approximately 10% of the life span)
exposure durations, all of which are derived based on an assumption of
continuous exposure throughout the duration specified. RfDs and RfCs
are generally used in noncancer health assessments.
Source: http://www.epa.gov/iris/help_ques.htm#rfd
A slope factor is an upper bound, approximating a 95%
confidence limit, on the increased cancer risk from a lifetime
exposure to an agent by ingestion. This estimate, usually
expressed in units of proportion (of a population) affected per mg
of substance/kg body weight-day, is generally reserved for use in
the low-dose region of the dose-response relationship, that is, for
exposures corresponding to risks less than 1 in 100. A unit risk is
an upper-bound excess lifetime cancer risk estimated to result
from continuous exposure to an agent at a concentration of 1
µg/L in water or 1 µg/m3 in air. The interpretation of unit risk for a
substance in drinking water would be as follows: if unit risk =
2 x 10-6 per µg/L, 2 excess cancer cases (upper bound estimate)
are expected to develop per 1,000,000 people if exposed daily for
a lifetime to 1 µg of the substance in 1 liter of drinking water.
Source: http://www.epa.gov/iris/help_ques.htm#rfd
Exposure Assessment
Exposure assessment deals with the extent to which people are exposed. This
involves describing the nature and size of the population exposed and the
magnitude and duration of their exposure.
Exposure is the amount of substance
that is available for absorption; dose is
the amount of substance actually
absorbed.
The demographics of a population and
activity patterns affect types and levels of
exposure.
APTI course 400: Introduction to risk assessment / risk management for hazardous air pollutants.
There are two major ways to determine
pollutant concentration for exposure
assessment:
• Measurement (personal or ambient)
• Calculation
personal exposure
monitors (PEMs)
Risk characterization
Risk characterization combines the data and inferences from
hazard identification, dose-response assessment, and exposure
assessment to determine the likelihood that humans will
experience any of the health effects associated with a
substance.
APTI course 400: Introduction to risk assessment / risk management for hazardous air pollutants.
APTI course 400: Introduction to risk assessment / risk management for hazardous air pollutants.
風險度數值之估計可用以下三種方式之一或綜合二種以上之方式表示之：
（一）單位風險度（Unit Risk）:在低劑量線性（low-dose
linearity）假設下，單位癌症風險度即為由於在整個生命期中持續不斷地暴
露於某一致癌物質特定濃度下，所增加之生命期癌症發生風險度。典型單位
風險度之表示，包括存在於飲水或食物中經口攝入者以ppm-1 或ppb-1 表示；
存在於空氣中經呼吸道攝入者以ppm-1 或 (μg/m3)-1 表示；經皮膚吸收者以
(mg/m2) -1 表示之。
（二）劑量相當於某一給定之危險程度（Dose Corresponding to a
Given Level of Risk）: 此種方式相當有用，尤其是在使用非線性外插模式
時，單一劑量風險度必定與其他不同劑量所造成之綜合風險度有所不同。
（三）個體及族群的風險度（Individual and Population Risks）:風
險特徵描述可以用個體在生命期中所增加之風險度來表示，亦可以用在某一
暴露族群中每年所產生之癌症病患增加數來表示之。
以上三種方式不管選擇那一種方式，在風險度數值估計上，其精確度及
準確度均需達到某種要求以上。在進行風險度估計時，由於可能同時暴露於
多種致癌性物質中，故依加成原理應將其風險度相加，但若有特殊資料顯示
違反加成原理時，則需另外考慮之。與已知致癌性物質相互作用之輔助致癌
因子（cocarcinogens）、促進因（promotors）及起始因子（initiators）
則需以個案方式考慮之。無論使用何種方法進行風險特徵描述，風險度數值
的估計不能單獨存在，而必須包含其各種基本假設及不確定性。
健康風險評估技術規範
http://ivy5.epa.gov.tw/epalaw/search/LordiDispFull.aspx?ltype=03&lname=33
10
開發單位於辦理環境影響評估之健康風險評估作業時，應依
本規範就營運階段可能運作或運作時衍生之危害性化學物質，
辦理開發行為影響範圍內居民健康之增量風險評估。
健康風險評估在空氣品質管理之應用
http://www.ctci.org.tw/public/Attachment/253016323071.pdf
中部科學工業園區第三期發展區（后里基地－七星農場部分）
開發計畫健康風險評估報告
http://eiareport.epa.gov.tw/eiaweb/DownloadFiles.ashx?shcode=0972018A
&sfilename=000.PDF
100年度六輕相關計畫之特定有害空氣污染物所致健康風險
評估計畫報告
http://eiareport.epa.gov.tw/EIAWEB/DownloadFiles.ashx?shcode=1011098A
&sfilename=C00.PDF
燁民實業健康風險評估報告
http://eiareport.epa.gov.tw/eiaweb/DownloadFiles.ashx?shcode=1030051X
&sfilename=A09.PDF
Hazard identification and
dose-response assessment
• USEPA, Integrated Risk Information System (IRIS): Site help
and tools, http://www.epa.gov/iris/help_start.htm ; Download IRIS,
http://www.epa.gov/iris/standal.html ;
• California Department of Toxic Substances Control: Toxics
Information Databases,
https://www.dtsc.ca.gov/PollutionPrevention/GreenChemistryInitiative/G
CToxicInfo.cfm
• International Agency for Research on Cancer, IARC,
http://www.iarc.fr/
• 行政院環保署「化學物質毒理資料庫」
http://flora2.epa.gov.tw/MainSite
• 行政院勞工安全衛生研究所「物質安全資料表資料庫」
http://www.iosh.gov.tw/msds.htm
下表為某健康風險分析中所用的化學物質毒理資料，請
解釋此表中各名詞的意義，並到各資料庫查出其值。
無註記來自IRIS；#標記來自OEHHA；*標記表示為HARP 使用參數；--標記表示無資料。
Source: http://eiareport.epa.gov.tw/eiaweb/DownloadFiles.ashx?shcode=1030051X&sfilename=A09.PDF
Exposure Assessment
• USEPA, Fate, Exposure, and Risk Analysis (FERA),
http://www2.epa.gov/fera
• California Department of Toxic Substances Control: CalTox
2.3, https://www.dtsc.ca.gov/AssessingRisk/caltox.cfm
• California ARB: Hotspots Analysis Reporting Program (HARP),
http://www.arb.ca.gov/toxics/harp/harp.htm