Air toxics and indoor air quality in Australia

State of knowledge report
Environment Australia, 2001
ISBN 0 6425 4739 4

Part A: Air toxics (continued)

International approach to air toxics

The World Health Organization (WHO) has been evaluating the risks posed to human health by air pollution since the 1950s. WHO guideline values were first derived in 1958. In 1987, the WHO Regional Office for Europe published the Air Quality Guidelines for Europe. Since 1993, these guidelines have been revised and updated. In an Expert Task Force Meeting convened in December 1997 in Geneva, Switzerland, the Guidelines for Air Quality were extended to provide global coverage and applicability, and the issues of air quality assessment and control were addressed in more detail. The WHO Guidelines for Air Quality (2000) document is the outcome of the consensus deliberations of the WHO Expert Task Force.

The WHO Guidelines for Air Quality provide a basis for protecting public health from the adverse effects of environmental pollutants and for eliminating, or reducing to a minimum, contaminants that are known or likely hazards to human health and well-being. The Guidelines provide background information and guidance to governments for making risk management decisions, particularly in setting standards. It also provides assistance to governments developing local air quality control measures.

An electronic version of this report is available from the web site of the World Health Organization at www.who.int/peh/ .

2.2 OECD urban air quality indicators

The OECD implemented the 'Advanced Air Quality Indicators and Reporting' project in recognition of the fact that air quality data monitoring and reporting vary considerably among OECD member countries. The objectives of the project were:

to improve the comparability of the status of air quality between regions, countries, cities and site categories of the OECD;
to present national, regional and OECD-wide trends for specific site categories by summarising measurements from a large number of monitoring stations; and
to identify the relationship between population data and exposure indicators in order to show the relationship between air quality and health.

The project focused on six air pollutants of major importance (carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulphur dioxide) and selected human health and ecosystem protection specific indicators for each.

In addition, a first attempt was made to identify 15 indicators for hazardous air pollutants 5 heavy metals and 10 specific volatile organic compounds (see Table 2.1). The OECD defined HAPs as:

Gaseous, aerosol or particulate contaminants present in the ambient air in trace amounts with characteristics (toxicity, persistence) so as to be a hazard to human health, plant and animal life.

Table 2.1: OECD preliminary list of urban hazardous air pollutant indicators
Pollutant	Measurement period	Emission source categories
Metals in suspended particulate matter (ng/m³)
Cadmium Mercury Lead Vanadium Nickel	Annual average	Process emissions (metal production, batteries, electrical apparatus), waste incineration, fuel combustion from stationary and mobile sources
Volatile organic compounds (mg/m³)
Ethene Propene n-Butene	Annual average	Motor vehicles (representative for photochemically active pollutants)
1,3-Butadiene Formaldehyde Benzene	Annual average	Motor vehicles and petroleum refining
Toluene	Maximum of daily (24-hour) average	Motor vehicles
Benzo[a]pyrene (ng/m³)	Annual average	Particulate matter from fuel (diesel, gasoline) use and small combustion sources
Trichloroethylene	Maximum of daily (24-hour) average	Solvent use (degreasing, surface cleaning, inks and adhesives)
Dioxins (TEQ/m³)	Annual average	Public health concern due to waste incineration, incomplete combustion of organochlorines in fuels and products
Black smoke or soot (mg/m³)	Annual average	Surrogate HAP indicator

Notes:
TEQ = toxic equivalents;
HAP = hazardous air pollutants

Source: OECD (1999).

The OECD selected its 15 priority HAPs using the following criteria:

significant potential for outdoor exposure;
significant health or ecotoxic implications;
monitoring in an adequate number of OECD member countries and a sufficient number of sites so that adequate representative data were available to derive the indicator; and
emissions by a range of industrial sources, and therefore not process specific.

In selecting the 15 HAPs, the OECD focused on chemical agents, although it recognised the important health effects of other hazardous substances, including physical agents such as radionuclides, ionising and non-ionising radiation, biological agents (microbes) and fibres such as asbestos.

The project proposed a preliminary method for assessing and presenting estimated cumulative cancer risk for a number of hazardous air pollutants known to be carcinogenic. The study also provided a preliminary assessment of the status and trends in air quality in the various OECD regions. The proposed methodology is expected to improve comparative air quality analyses, assessment and communication at international level.

2.3 US EPA's approach

2.3.1 New urban air toxics program

On 19 July 1999, the US EPA finalised its National Air Toxics Program – The Integrated Urban Strategy, which identifies a priority list of 33 urban air toxics (Table 2.2) and targets priority source categories (Table 2.3).

Table 2.2: US EPA Integrated Urban Strategy priority list of 33 urban air toxics
Acetaldehyde	Ethylene oxide
Acrolein	Formaldehyde
Acrylonitrile	Hexachlorobenzene (HCB)
Arsenic compounds	Hydrazine
Benzene	Lead compounds
Beryllium compounds	Manganese compounds
1,3-butadiene	Mercury compounds
Cadmium compounds	Methylene chloride
Carbon tetrachloride	Nickel compounds
Chloroform	Polychlorinated biphenyls (PCBs)
Chromium compounds	Polycyclic organic matter
Coke oven emissions	Quinoline
Dioxin	1,1,2,2-Tetrachloroethane
Ethylene dibromide	Perchloroethylene
Propylene dichloride	Trichloroethylene
1,3-Dichloropropene	Vinyl chloride
Ethylene dichloride

Table 2.3: The 29 industry source categories identified by US EPA that contribute most to the emissions of the 33 priority urban air toxics in the United States
Industry source categories requiring regulation	Source categories already subject to standards or that will be subject to standards over next five years
Cyclic crude and intermediate production Municipal landfills Flexible polyurethane foam fabrication operations Oil and natural gas production Hospital sterilisers Paint stripping operations Industrial inorganic chemical manufacturing Plastic materials and resins manufacturing Industrial organic chemical manufacturing Publicly owned treatment works Mercury cell chlor-alkali plants Synthetic rubber manufacturing Gasoline distribution (Stage I)	Chromic acid anodising Commercial sterilisation facilities Other solid waste incinerators (human/animal cremation) Decorative chromium electroplating Dry cleaning facilities Halogenated solvent cleaners Hard chromium electroplating Hazardous waste combustors Industrial boilers Institutional/commercial boilers Medical waste incinerators Municipal waste combustors Open burning of scrap tyres Secondary lead smelting Stationary internal combustion engines Portland cement manufacturing

The development of this strategy was the result of a directive from the United States Congress to the US EPA during passage of amendments to the US EPA Clean Air Act in 1990. Congress was motivated by the desire to identify and manage sources of hazardous air pollutants in urban areas that pose a threat to human health.

Specifically, the US EPA was directed to identify at least 30 priority air toxics (from an original list of 189 compounds, Table 2.4) that present the greatest threat to urban populations and ensure that sources that account for 90% or more of the aggregate emissions are subject to regulation. In addition, a national strategy was to be developed to reduce cancer incidence attributable to these pollutants by at least 75%.

In finalising its urban air toxics strategy, the US EPA identified 29 industry source categories that contribute to the emissions of the 33 priority air toxics. As indicated in Table 2.3, of the 29 industry source categories, the US EPA has regulations under development or completed for 16 and intends to develop regulations for the remaining 13 over the next five years.

The current United States Government Performance Results Act includes commitments specifying a 75% reduction in air toxics emissions from 1993 levels.

The US EPA strategy and the supporting technical documents provided useful background for the development of the State of Knowledge Report: Air Toxics and Indoor Air Quality in Australia and will aid the development of subsequent approaches to the management of air toxics in our urban environment. Full details of the US EPA National Air Toxics Program – The Integrated Urban Strategy can be found on the internet.¹

Table 2.4: US EPA list of 189^a air toxics
Pollutant (CASR No.)	Pollutant (CASR No.)
Acetaldehyde (75-07-0)	Hexane (110-54-3)
Acetamide (60-35-5)	Hydrazine (302-01-2)
Acetonitrile (75-05-8)	Hydrochloric acid (hydrogen chloride [gas only]) (7647-01-0)
Acetophenone (98-86-2)	Hydrogen fluoride (hydrofluoric acid) (7664-39-3)
2-Acetylaminofluorene (53-96-3)	Hydroquinone (123-31-9)
Acrolein (107-02-8)	Isophorone (78-59-1)
Acrylamide (79-06-1)	Maleic anhydride (108-31-6)
Acrylic acid (79-10-7)	Methanol (67-56-1)
Acrylonitrile (107-13-1)	Methoxychlor (72-43-5)
Allyl chloride (107-05-1)	Methyl bromide (bromomethane) (74-83-9)
4-Aminobiphenyl (92-67-1)	Methyl chloride (chloromethane) (74-87-3)
Aniline (62-53-3)	Methyl chloroform (1,1,1-trichloroethane) (71-55-6)
o-Anisidine (90-04-0)	Methyl ethyl ketone (2-butanone) (78-93-3)
Asbestos (1332-21-4)	Methylhydrazine (60-34-4)
Benzene (including benzene from gasoline) (71-43-2)	Methyl iodide (iodomethane) (74-88-4)
Benzidine (92-87-5)	Methyl isobutyl ketone (hexone) (108-10-1)
Benzotrichloride (98-07-7)	Methyl isocyanate (624-83-9)
Benzyl chloride (100-44-7)	Methyl methacrylate (80-62-6)
Biphenyl (92-52-4)	Methyl tert-butyl ether (1634-04-4)
Bis(2-ethylhexyl)phthalate (DEHP) (117-81-7)	4,4'-Methylenebis(2-chloroaniline) (101-14-4)
Bis(chloromethyl) ether (542-88-1)	Methylene chloride (dichloromethane) (75-09-2)
Bromoform (75-25-2)	4,4'-Methylenediphenyl diisocyanate (MDI) (101-68-8)
1,3-butadiene (106-99-0)	4,4'-Methylenedianiline (101-77-9)
Calcium cyanamide (156-62-7)	Naphthalene (91-20-3)
Caprolactam (Removed 6/18/96) (105-60-2)	Nitrobenzene (98-95-3)
Captan (133-06-2)	4-Nitrobiphenyl (92-93-3)
Carbaryl (63-25-2)	4-Nitrophenol (100-02-7)
Carbon disulfide (75-15-0)	2-Nitropropane (79-46-9)
Carbon tetrachloride (56-23-5)	N-Nitroso-N-methylurea (684-93-5)
Carbonyl sulfide (463-58-1)	N-Nitrosodimethylamine (62-75-9)
Catechol (120-80-9)	N-Nitrosomorpholine (59-89-2)
Chloramben (133-90-4)	Parathion (56-38-2)
Chlordane (57-74-9)	Pentachloronitrobenzene (quintobenzene) (82-68-8)
Chlorine (7782-50-5)	Pentachlorophenol (87-86-5)
Chloroacetic acid (79-11-8)	Phenol (108-95-2)
2-Chloroacetophenone (532-27-4)	p-Phenylenediamine (106-50-3)
Chlorobenzene (108-90-7)	Phosgene (75-44-5)
Chlorobenzilate (510-15-6)	Phosphine (7803-51-2)
Chloroform (67-66-3)	Phosphorus compounds (NA)
Chloromethyl methyl ether (107-30-2)	Phthalic anhydride (85-44-9)
Chloroprene (126-99-8)	Polychlorinated biphenyls (aroclors) (1336-36-3)
Cresol/Cresylic acid (mixed isomers) (1319-77-3)	1,3-Propane sultone (1120-71-4)
o-Cresol (95-48-7)	beta-Propiolactone (57-57-8)
m-Cresol (108-39-4)	Propionaldehyde (123-38-6)
p-Cresol (106-44-5)	Propoxur (Baygon) (114-26-1)
Cumene (98-82-8)	Propylene dichloride (1,2-dichloropropane) (78-87-5)
2,4-D (2,4-Dichlorophenoxyacetic acid) (including salts and esters) (NA)	Propylene oxide (75-56-9)
DDE (1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene) (72-55-9)	1,2-Propylenimine (2-methylaziridine) (75-55-8)
Diazomethane (334-88-3)	Quinoline (91-22-5)
Dibenzofuran (132-64-9)	Quinone (p-benzoquinone) (106-51-4)
1,2-Dibromo-3-chloropropane (96-12-8)	Styrene (100-42-5)
Dibutyl phthalate (84-74-2)	Styrene oxide (96-09-3)
1,4-Dichlorobenzene (106-46-7)	2,3,7,8-Tetrachlorodibenzo-p-dioxin (1746-01-6)
3,3'-Dichlorobenzidine (91-94-1)	1,1,2,2-Tetrachloroethane (79-34-5)
Dichloroethyl ether (Bis[2-chloroethyl]ether) (111-44-4)	Tetrachloroethylene (perchloroethylene) (127-18-4)
1,3-Dichloropropene (542-75-6)	Titanium tetrachloride (7550-45-0)
Dichlorvos (62-73-7)	Toluene (108-88-3)
Diethanolamine (111-42-2)	Toluene-2,4-diamine (95-80-7)
Diethyl sulfate (64-67-5)	2,4-Toluene diisocyanate (584-84-9)
3,3'-Dimethoxybenzidine (119-90-4)	o-Toluidine (95-53-4)
4-Dimethylaminoazobenzene (60-11-7)	Toxaphene (chlorinated camphene) (8001-35-2)
N,N-Dimethylaniline (121-69-7)	1,2,4-Trichlorobenzene (120-82-1)
3,3'-Dimethylbenzidine (119-93-7)	1,1,2-Trichloroethane (79-00-5)
Dimethylcarbamoyl chloride (79-44-7)	Trichloroethylene (79-01-6)
N,N-Dimethylformamide (68-12-2)	2,4,5-Trichlorophenol (95-95-4)
1,1-Dimethylhydrazine (57-14-7)	2,4,6-Trichlorophenol (88-06-2)
Dimethyl phthalate (131-11-3)	Triethylamine (121-44-8)
Dimethyl sulfate (77-78-1)	Trifluralin (1582-09-8)
4,6-Dinitro-o-cresol (including salts) (NA)	2,2,4-Trimethylpentane (540-84-1)
2,4-Dinitrophenol (51-28-5)	Vinyl acetate (108-05-4)
2,4-Dinitrotoluene (121-14-2)	Vinyl bromide (593-60-2)
1,4-Dioxane (1,4-Diethyleneoxide) (123-91-1)	Vinyl chloride (75-01-4)
1,2-Diphenylhydrazine (122-66-7)	Vinylidene chloride (1,1-dichloroethylene) (75-35-4)
Epichlorohydrin (l-Chloro-2,3-epoxypropane) (106-89-8)	Xylenes (mixed isomers) (1330-20-7)
1,2-Epoxybutane (106-88-7)	o-Xylene (95-47-6)
Ethyl acrylate (140-88-5)	m-Xylene (108-38-3)
Ethylbenzene (100-41-4)	p-Xylene (106-42-3)
Ethyl carbamate (urethane) (51-79-6)
Ethyl chloride (chloroethane) (75-00-3)	Antimony compounds
Ethylene dibromide (dibromoethane) (106-93-4)	Arsenic compounds (inorganic including arsine)
Ethylene dichloride (1,2-dichloroethane) (107-06-2)	Beryllium compounds
Ethylene glycol (107-21-1)	Cadmium compounds
Ethylenimine (aziridine) (151-56-4)	Chromium compounds
Ethylene oxide (75-21-8	Cobalt compounds
Ethylene thiourea (96-45-7)	Coke oven emissions
Ethylidene dichloride (1,1-dichloroethane) (75-34-3)	Cyanide compounds^b
Ethylidene dichloride (1,1-dichloroethane) (75-34-3)
Formaldehyde (50-00-0)	Glycol ethers^c
Heptachlor (76-44-8)	Lead compounds
Hexachlorobenzene (118-74-1)	Manganese compounds
Hexachlorobutadiene (87-68-3)	Mercury compounds
1,2,3,4,5,6-Hexachlorocyclohexane (all stereo isomers, including lindane) (NA)	Fine mineral fibres^d
Hexachlorocyclopentadiene (77-47-4)	Nickel compounds
Hexachloroethane (67-72-1)	Polycyclic organic matter^e
Hexamethylene diisocyanate (822-06-0)	Radionuclides (including radon) ^f
Hexamethylphosphoramide (680-31-9)	Selenium compounds

Notes:
CASR No. = Chemical Abstracts Service Registry Number;
NA = not applicable
^a There are now 188 HAPs under the US EPA Clean Air Act. This follows deletion of caprolactam from the list.
^b X'CN where X = H' or any other group where a formal dissociation may occur. (eg KCN or Ca(CN) ²)
^c Includes mono- and di- ethers of ethylene glycol, diethylene glycol, and triethylene glycol R-(OCH₂CH₂)n -OR' where n = 1, 2, or 3; R = alkyl or aryl groups; R' = R, H, or groups which, when removed, yield gl.ycol ethers with the structure: R-(OCH₂CH)n-OH. Polymers are excluded from the glycol category.
^d Includes mineral fibre emissions from facilities manufacturing or processing glass, rock, or slag fibres (or other mineral derived fibres) of average diameter 1 micrometer or less.
^e Includes organic compounds with more than one benzene ring, and which have a boiling point greater than or equal to 100°C.
^f A type of atom that spontaneously undergoes radioactive decay.

2.3.2 US EPA persistent, bioaccumulative and toxic (PBT) chemicals initiative

In 1998, the US EPA released its agency-wide multimedia strategy for priority persistent, bioaccumulative and toxic pollutants (PBT Strategy). This program aims to reduce risks from, and exposures to, priority PBT chemicals, both organic and inorganic.

At this stage, the PBT Strategy covers many of the chemicals covered by the newly agreed UNEP Persistent Organic Pollutants (POPs) Convention (see Table 2.5 below). More information on POPs initiative can be found in Section 1.3.5 of this report.

The US EPA PBT Strategy encompasses the principle of increased coordination among US EPA national and regional programs and commits the EPA to create a cross-office system that will address the cross-media issues associated with priority PBT pollutants.

The goal of the PBT Strategy is to identify and reduce risks to human health and the environment from current and future exposure to priority PBT pollutants. To attain this goal, EPA has identified several guiding principles:

address problems on multimedia basis through integrated use of all agency tools;
coordinate with, and build on, relevant international efforts;
coordinate with relevant Federal programs and agencies;
stress cost-effectiveness (eg amount of PBT removed for dollars spent);
involve stakeholders;
emphasise innovative technology and pollution prevention;
protect vulnerable subpopulations;
base decisions on sound science; and
use measurable objectives and assess performance.

Table 2.5: Chemicals listed under the PBT program and POPs convention
	US EPA PBT program	UNEP POPs convention
Aldrin	Aldrin/dieldrin
Alkyl-lead
Benzo[a]pyrene
Chlordane
DDT and its metabolites		DDT
Dieldrin	Aldrin/dieldrin
Dioxins and furans
Endrin
Hexachlorobenzene
Heptachlor
Mercury and its compounds
Mirex
Octachlorostyrene
Polychlorinated biphenyls
Toxaphene

Notes:
PBT = persistent, bioaccumulative and toxic;
POP = persistent organic pollutant

The PBT Strategy outlines an approach to achieving PBT risk reductions that includes the development and implementation of national action plans for priority PBT pollutants. The action plans will consider enforcement and compliance, international coordination, place-based remediation of existing PBT contamination, research, technology development and monitoring, community and sector-based projects, the use of outreach and public advisories, and opportunities to integrate efforts across chemicals. More information on the US EPA PBT initiative can be found at the US EPA website.²

2.3.3 US Centres for Disease Control and Prevention (CDC) – National report on Human Exposure to Environmental Chemicals

In March 2001 the US Centres for Disease Control and Prevention (CDC) released the first National Report on Human Exposure to Environmental Chemicals. Levels of environmental chemicals were measured in blood and urine samples collected from participants in the 1999 CDC National Health and Nutrition Survey (NHANES) – an ongoing national health survey of the US population. The report will be produced each year and in the future will also include data from other large exposure studies and studies of exposure of particular population groups.

This CDC initiative will provide better information on levels of exposure to environmental chemicals, and over time, what these levels mean for public health. This information can be used to help prevent disease resulting from exposure to environmental chemicals. Specific objectives of the CDC first National Report on Human Exposure to Environmental Chemical may be summarised as follows:

to determine whether selected environmental chemicals are entering the bodies of the population and at what levels;
to ascertain the proportion of the population that have elevated levels of particular chemicals (for those chemicals with known toxicity levels);
to assess the effectiveness of efforts to reduce exposure to environmental chemicals;
to establish reference ranges to determine whether a person has unusually high levels of an environmental chemical;
to track trends in exposure over time;
to determine whether levels of environmental chemicals are higher in particular population groups such as women of childbearing age or children; and
to help set research priorities.

The 2001 report measured the exposure of the US population to 27 environmental chemicals including metals, pesticide metabolites, phthalate metabolites and cotinine (a nicotine metabolite which indicates exposure to environmental tobacco smoke). It is proposed to gradually increase the number of chemicals that are measured to approximately 100. Chemicals being considered for future inclusion include volatile organic compounds, polycyclic aromatic hydrocarbons, dioxins, furans, polychlorinated biphenyls, trihalomethanes, haloacetic acids, carbamate pesticides, and organochlorine pesticides.

The CDC had previously assessed exposure to three of the chemicals in the 2001 report (lead, cadmium and cotinine) and observed some trends, while noting that the sample size was small and that data from future years will be needed to confirm these findings.

Key findings included a 75% reduction in cotinine levels of non-smokers compared to 1998–1991, indicating a dramatic fall in exposure to environmental tobacco smoke, but the report noted that more than half of US youth are still exposed to environmental tobacco smoke. A continuing decline in blood lead levels of children was observed, although children living in high risk environments for lead exposure remain a major public health concern. High levels of two phthalate metabolites were found, prompting the CDC to conduct additional studies to examine the pathways by which these phthalates enter the body.

2.4 Canada

2.4.1 National Air Pollution Surveillance Network

The National Air Pollution Surveillance (NAPS) Network was established in 1969 to monitor and assess the quality of ambient air in Canadian urban centres. In 1998, the network consisted of 239 stations in 136 cities, with 430 continuous analysers for criteria pollutants and 219 samplers for criteria pollutants and VOCs. Originally, the NAPS network concentrated on monitoring the criteria pollutants. Although these continue to be a priority, other air pollutants of concern are now monitored.

In May 1984, Environment Canada began a program to monitor inhalable particles (PM₁₀ and PM_2.5) and these are now monitored at 95 sites. Portions of the samples are analysed for constituents of atmospheric particulate matter, including 50 elements, 14 inorganic and organic anions, and 11 inorganic cations.

An air toxics monitoring program began in 1989. Aromatics, aldehydes, ketones, PAHs, dioxins and furans are monitored at 40 urban and rural locations. Table 2.6 provides an overview of when various pollutants were introduced to the NAPS Network.

Table 2.6: Compounds measured and analysed from the National Air Pollution Surveillance (NAPS) Network
Parameter	Species measured	Start year
Criteria pollutants	SO₂, CO, NO₂, O₃ and total suspended particles (TSP)	1970
Particles and metals	PM₁₀, PM_2.5, sulfate, acidic aerosols and 48 elements (eg lead, zinc)	1984
Volatile organic compounds	C₂ to C₁₂ (eg benzene), chlorinated hydrocarbons (eg tetrachloroethylene) and carbonyls (eg formaldehyde)	1989
Semivolatile organics	Polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans	1989–95

Source: Adapted from: Turle (1999).

2.4.2 Accelerated Reduction/Elimination of Toxics Program

The Accelerated Reduction/Elimination of Toxics (ARET) Program was conceived in 1991 as a voluntary response to a federal government challenge to reduce and eliminate industrial emissions of toxic substances (not all of these are air pollutants). Today, ARET is a multi-stakeholder pollution prevention and abatement initiative involving industry, health and professional organisations as well as governments across Canada. ARET stipulates reduction targets of 90% for 30 persistent, bioaccumulative and toxic (PBT) substances (the 'A1' list) and 50% for 87 other toxic substances (the 'A2', 'B1', 'B2' and 'B3' lists). ARET participants voluntarily agree to meet these targets, thus creating an open and non-prescriptive approach to pollution prevention. Table 2.8 summarises the goals for the ARET program.

By the time the ARET challenge ran its course at the end of 2000, participants were expected to have collectively reduced their emissions of the 30 substances on the A1 list by 71% (short of the 90% target) and emissions of the 87 other ARET substances by about 80% (well above the original 50% target). These percentages represent reductions of 29 000 tonnes in toxic emissions.

Table 2.7: Projected and targeted emission reductions from base year levels
		Goal for 2000 (%)	Projected for 2000 (%)	Projected emissions in 2000 (tonnes)
List A1	(30 PBT substances)	90	71	317
List A2	(2 substances for which consensus was not reached over whether they met the PBT criteria)	none set	84	24
List B1	(8 B and T substances)	50	83	9.8
List B2	(33 P and T substances)	50	74	2605
List B3	(44 T substances)	50	80	5341
Overall		50	78	8296.8

Notes:
B = bioaccumulative;
P = persistent;
T = toxic

Source: Environment Canada (1999).

Substance selection

The criteria used for screening substances for inclusion in the ARET lists were toxicity, persistence and bioaccumulation. Substances were selected on the basis of their intrinsic properties only; no consideration was given to quantities released, the medium of release or quantities in the environment. As a consequence, no inference can be made about their relative risk. In addition, the grouping of substances into lists is not meant to imply that all substances within a list are of equal priority since each list represents a broad range of scores for the criteria.

Tables 2.8–2.12 give the substances included in Lists A1, A2, B1, B2 and B3. The Chemical Abstracts Service Registry Number (CASR No.) is given in brackets following the name of the substance. The selection process was unable to take into account specific metal compounds. Thus, scores for metals were based on a composite score for several metal species; in these cases a CASR number is not applicable. The source for these tables (ARET 1999) can be accessed via the internet.³

Table 2.8: ARET list A1 – substances that meet or exceed criteria for toxicity, bioaccumulation and persistence^a
Polycyclic aromatic hydrocarbons	Chlorinated organics
Benzo[a]anthracene (56-55-3)	Polychlorinated biphenyls (PCBs) (NA)
Benzo[a]pyrene (50-32-8)	Hexachlorobenzene (118-74-1)
Benzo[e]pyrene (192-97-2)	alpha-Hexachlorocyclohexane (319-84-6)
Benzo[b]fluoranthene (205-99-2)	gamma-Hexachlorocyclohexane (58-89-9)
Benzo[j]fluoranthene (205-82-3)	4,4'-Methylenebis(2-chloroaniline) (101-14-4)
Benzo[k]fluoranthene (207-08-9)	Octachlorostyrene (29082-74-4)
Benzo[g,h,i]perylene (191-24-2)	Pentachlorophenol (87-86-5)
Chrysene (218-01-9)	2,3,7,8-Tetrachlorodibenzofuran (51207-31-9)
Dibenz[a,h]anthracene (53-70-3)	2,3,7,8-Tetrachlorodibenzo-p-dioxin (1746-01-6)
Dibenzo[a,i]pyrene (189-55-9)	Metal compounds
Dibenz[a,j]acridine (224-42-0)	Methyl mercury (22967-92-6)^b
7H-dibenzo[c,g]carbazole (194-59-2)	Tributyltin (688-73-3)
Fluoranthene (206-44-0)	Nitro-polycyclic aromatic hydrocarbons
Indeno[1,2,3-c,d]pyrene (193-39-5)	1,6-dinitropyrene (42397-64-8)
Perylene (198-55-0)	1,8-dinitropyrene (42397-65-9)
Phenanthrene (85-01-8)
Pyrene (129-00-0)

Notes:
^a Numbers in brackets represent Chemical Abstracts Service Registry Number.
^b See also mercury (Table 2.12).
NA = not applicable

ARET's vision for substances on list A1 is the virtual elimination of emissions into the environment from human activities. The short-term goal is for a 90% reduction in emissions by 2000.

Table 2.9: ARET list A2 – substances for which consensus could not be reached on whether they meet all criteria^a
1,4-dichlorobenzene (106-46-7)^b
Cadmium (inhalable and soluble inorganic)^c (NA)

Notes:
^a Numbers in brackets represent Chemical Abstracts Service Registry Number.
^b The toxicity criterion was met for possible carcinogenicity by accepting IARC (International Agency for Research on Cancer) classification of "possible human carcinogen".
^c For cadmium, actions may be tailored to such compunds as CdCO₃, CdCO₂, CdCl₂, CdO and CdSO₄. The concept of virtual elimination of discharges for metals is under discussion and was not resolved by ARET.
NA = not applicable

ARET's goal for substances on list A2 is for the reduction of emissions to levels that are insufficient to cause harm. The short-term goal is for 'best effort' reduction in emissions.

Table 2.10: ARET list B1 – substances that meet or exceed criteria for toxicity and bioaccumulation^a
Polycyclic aromatic hydrocarbons
Anthracene (120-12-7)
7,12-dimethylbenzo[a]anthracene (57-97-6)
Dimethylnaphthalene (28804-88-8)
Chlorinated organics
3,3'-dichlorobenzidine (91-94-1)
Hexachlorocyclopentadiene (77-47-4)
2,4,6-trichlorophenol (88-06-02)
Other
Tetraethyl lead (78-00-2)^b
Bis(2-ethylhexyl)phthalate (117-81-7)

Notes:
^a Numbers in brackets represent Chemical Abstracts Service Registry Number.
^b Degrades to lead, which is persistent (see Table 2.11)

For the list B substances, the vision is reduction of emissions to levels that are insufficient to cause harm. The short-term goal is a 50% reduction by 2000.

Table 2.11: ARET list B2 – substances that meet or exceed persistence and toxicity criteria^a
Polycyclic aromatic hydrocarbons	Metal compounds
Benzo[a]fluorene (238-84-6)	Arsenic (inorganic) (NA)
Benzo[b]fluorene (30777-19-6)	Asbestos (1332-21-4)
Dibenz[a,h]acridine (226-36-8)	Beryllium (7440-41-7)
Chlorinated organics	Chromium (Cr6+) (NA)
a-Chlorotoluene (100-44-7)	Cobalt (inorganic, soluble) (NA)
Bis(2-chloroethyl)ether (111-44-4)	Copper (inorganic salts) (NA)
Bromodichloromethane (75-27-4)	Lead (all forms except alkyl)^b (NA)
Carbon tetrachloride (56-23-5)	Mercury (elemental and inorganic)^c (NA)
Chloroform (67-66-3)	Nickel (inorganic, inhalable, soluble) (NA)
Chlorodibromomethane (124-48-1)	Silver (soluble inorganic salts) (NA)
1,2-dichloroethane (107-06-2)	Uranium (inorganic, inhalable, soluble) (NA)
Methylene chloride (75-09-2)	Zinc (inorganic, inhalable, soluble) (NA)
1,1,2,2-Tetrachloroethylene (127-18-4)	Other
2,3,4,6-Tetrachlorophenol (58-90-2)	o-Anisidine (90-04-0)
	Cyanides (57-12-5)
	4,6-Dinitro-o-cresol (534-52-1)
	1,4-Dioxane (123-91-1) Ethylene oxide (75-21-8)
	2-Naphthylamine (91-59-8)
	2-Nitropropane (79-46-9)
	Thiourea (62-56-6)

Notes:
^a Numbers in brackets represent Chemical Abstracts Service Registry Number.
^b See also tetraethyl lead (see Table 2.10).
^c See also methyl mercury (see Table 2.8)
NA = not applicable

Table 2.12: RET list B3 – substances that meet or exceed toxicity criteria^a
Chlorinated organics	Nitrosamines
Bis(chloromethyl)ether (542-88-1)	N-Nitrosodimethylamine (62-75-9)
Epichlorohydrin (106-89-8)	N-Nitrosodiphenylamine (86-30-6)
1-Bromo-2-chloroethane (107-04-0)	N-Nitroso-di-n-propylamine (621-64-7)
1-Chloro-4-nitrobenzene (100-00-5)	Other
1,2-Dibromo-3-chloropropane (96-12-8)	Acetaldehyde (75-07-0)
1,2-Dichlorobut-3-ene (760-23-6)	Acetamide (60-35-5)
2,4-Dichlorophenol (120-83-2)	Acrolein (107-02-8)
1,3-Dichloropropene (542-75-6)	Acrylamide (79-06-1)
1,1,2-Trichloroethylene (79-01-6)	Acrylonitrile (107-13-1)
Aromatics	1,3-Butadiene (106-99-0)
4-Aminoazobenzene (60-09-3)	Chlorine dioxide (10049-04-4)
4-Aminobiphenyl (92-67-1)	n-Dodecane (112-40-3)
Aniline (62-53-3)	Ethanol (64-17-5)
Benzene (71-43-2)	Ethylene dibromide (106-93-4)
Benzidine (92-87-5)	Ethylene thiourea (96-45-7)
Dimethylphenol (mixed isomers) (1300-71-6)	Formaldehyde (50-00-0)
2,6-Dimethylphenol (576-26-1)	Hydrazine (302-01-2)
2,4-Dinitrotoluene (121-14-2)	Hydrogen sulphide (7783-06-4)
2,6-Dinitrotoluene (606-20-2)	Methyl isobutyl ketone (108-10-1)
1,2-Diphenylhydrazine (122-66-7)	4-Nitrosomorpholine (59-89-2)
2-Methylpyridine (109-06-8)	Quinoline (91-22-5)
Phenol (108-95-2)	Tetramethylthiuram disulphide (137-26-8)
Toluene diisocyanates (26471-62-5)	Vinyl bromide (593-60-2)

Note: ^a Numbers in brackets represent Chemical Abstracts Service Registry Number.

Table 2.13 illustrates the typical ranges of HAP concentration in urban areas in Canada and compares them with those found in western Europe, USA, Japan and Australia.

2.5 United Kingdom

In 1991, the United Kingdom Department of the Environment, Transport and Regions (UK DETR) established an Expert Panel on Air Quality Standards (EPAQS) 'to provide independent advice on air quality issues, in particular the levels of pollution at which no or minimal health effects are likely to occur'.

The Expert Panel's recommendations were adopted as the benchmark standards in the UK DETR National Air Quality Strategy. Copies of the final reports from the EPAQS are available on the internet at www.environment.detr.gov.uk/airq/aqs/ . At the time the SoK was printed EPAQS reports were available for the following pollutants:

criteria pollutants – particles, lead, nitrogen dioxide, sulphur dioxide, carbon monoxide and ozone.
air toxics – benzene, 1,3-butadiene and polycyclic aromatic hydrocarbons (PAHs).

Table 2.13: Typical ranges of HAPs concentrations in urban areas
Pollutant	Unit	Western Europe	Canada	USA	Japan	Australia
Metals
Cadmium	ng/m³	0.2–20	0.5–6.6		ND–5	0–6
Lead	ng/m³	20–1000	6–17		5.5–238	180–8000
Mercury	ng/m³	0.05–2	0.9–1.4		0.52–8.3	0–0.13
Nickel	ng/m³	1–20	1–7		0.64–34	0.00002–3.2
Vanadium	ng/m³	1–50	5–15		1.3–20.0
VOCs
Ethene	µ g/m³	0.5–33.9	2–10		0.43–19.6
Propene	µ g/m³	0.8–12.6	0.8–5.9		0.52–6.7
n-Butene	µ g/m³	0.9–12.7	1–3.7
1,3-butadiene	µ g/m³	0.74	0.1–0.9	0.068–0.7	ND–3.4	0.001–420
Formaldehyde	µ g/m³	0.5–32	1.8–4.5		ND–27.8	0.026–0.68
Benzene	µ g/m³	0.8–30	1.4–8.5	0.29–10.0	1.0–25.3	0.18–3.0
Toluene	µ g/m³	0.5–58.5	0.9–166.8	0.61–58.1	0.27–130	0.45–10.5
Benzo[a]pyrene	ng/m³	0.2–20	0–1.6		0.015–11
Trichloroethylene	µ g/m³	0.2–15	0.1–0.8	1.03–3.30	ND–24.1
Dioxins	TEQ^a	0.003^b–0.23^c	0.034–0.2^c		ND–2.7

Notes:
^a International Toxicity Equivalent.
^b 1,2,3,7,8-TCDD (pg/m³);
^c pg/m³.
Note: Years data refers to: Canada (1994, Dioxin and BaP: 1994–96); USA (1993); Western Europe (France 1987–89), Germany (1989), Netherlands (1988–89), Sweden (1990–93), Switzerland (1991–94), and UK (1993); Japan (1988–95); and Australia (EPA Victoria 1993)
ND = not detectable

Source: OECD (1999).

2.6 New Zealand air toxics program

In 1994, the New Zealand Ministry for the Environment released Ambient Air Quality Guidelines, which remain current. The guidelines contain advice on how air quality should be managed under the effects-based principles of the Resource Management Act 1991. In New Zealand, regional councils and unitary authorities are responsible for managing discharges into the air, and for ensuring that outdoor air is clean and healthy to breathe. To help them to achieve this, they can develop regional air quality plans under the Resource Management Act 1991. Guideline values were developed for eight common air pollutants – carbon monoxide (CO), particulate matter (PM₁₀), sulphur dioxide (SO₂), nitrogen dioxide (NO₂), hydrogen sulfide, fluoride, ozone and lead (see Table 2.6).

In addition, the 1994 guidelines contain a list of over 140 hazardous air contaminants (ie air toxics), based on those regulated by the United States Clean Air Act. It advocated a precautionary approach to minimise their emissions. The need to assess the significance of these compounds was also discussed, with a view to setting guidelines or standards in the future.

In 1998 the Ministry decided to review the guidelines to:

assess their effectiveness;
bring them up to date with recent research;
develop new guidance on managing hazardous air contaminants and protecting ecosystems; and
consider whether national environmental standards for air quality are needed.

Community consultation to progress this review was expected to commence during 2000 and to include the release of a discussion paper for public comment.

Table 2.14: Ambient air quality guidelines for New Zealand
Contaminant	Acceptable average level	Averaging period
Particles (PM₁₀)	120 mg/m³ 40 mg/m³	24-hour annual
Sulfur dioxide (SO₂)	500 mg/m³ 350 mg/m³ 125 mg/m³ 50 mg/m³	10-minute 1-hour 24-hour annual
Carbon monoxide (CO)	30 mg/m³ 10 mg/m³	1-hour 8-hour
Ozone	150 mg/m³ 100 mg/m³	1-hour 8-hour
Nitrogen dioxide (NO₂)	300 mg/m³ 100 mg/m³	1-hour 24-hour
Lead	0.5–1.0 mg/m³	3-month
Fluoride: special land use	1.8 mg/m³ 1.5 mg/m³ 0.8 mg/m³ 0.4 mg/m³ 0.25 mg/m³	12-hour 24-hour 7-day 30-day 90-day
Fluoride: general land use	3.7 mg/m³ 2.9 mg/m³ 1.7 mg/m³ 0.84 mg/m³ 0.5 mg/m³	12-hour 24-hour 7-day 30-day 90-day
Fluoride: conservation areas	0.1 mg/m³	90-day
Hydrogen sulfide (H₂S)	7 mg/m³	30-minute

Source: New Zealand Ministry for the Environment (1994)

The New Zealand list of priority hazardous air contaminants has already been developed as part of the review process. This list covers groups of compounds and includes specific indicator compounds from within these groups as follows:

volatile hydrocarbons – benzene, toluene, xylene and 1,3 butadiene
carbonyls – formaldehyde and acetaldehyde
polycyclic aromatic hydrocarbons – benzo[a]pyrene
metals – arsenic, mercury and chromium.

Organochlorines also form a group of priority compounds but are being considered separately under the Organochlorines Program which is developing tools to manage the impacts of organochlorines on human health and the environment. Emission standards for industrial sources, ambient guideline values, monitoring techniques and education are some of the management options being examined. A large-scale monitoring program was implemented in the early stages of the program to ascertain the level of dioxins and furans in various environmental media.

Emissions from motor vehicles are specifically covered by a Vehicle Fleet Emissions Control Strategy, developed by the Ministry for Transport. The strategy includes initiatives to tackle vehicle emissions in New Zealand in response to their impact on air quality. The initiatives include:

developing emission standards for new vehicles;
reviewing fuel specifications;
reviewing the Ambient Air Quality Guidelines;
introducing guidelines for identifying excessively smoky vehicles; and
promoting and demonstrating the application of Environmental Capacity Analysis to traffic management.

Footnotes:

¹ www.epa.gov/ttn/uatw/urban/urbanpg.html

² www.ec.gc.ca/aret

³ www.ec.gc.ca/aret

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