Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019)

Ghana Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions Standard 1236 of 2019 Legislation as at 31 December 2019 There may have been updates since this file was created. PDF created on 7 April 2025 at 14:22. View online About this collection The legislation in this collection has been reproduced as it was originally printed in the Government Gazette, with improved formatting and with minor typographical errors corrected. All amendments have been applied directly to the text and annotated. A scan of the original gazette of each piece of legislation (including amendments) is available for reference. www.laws.africa info@laws.africa FRBR URI: /akn/gh/act/standard/2019/1236/eng@2019-12-31 There is no copyright on the legislative content of this document. This PDF copy is licensed under a Creative Commons Attribution 4.0 License (CC BY 4.0). Share widely and freely. i https://resolver.laws.africa/resolve/akn/gh/act/standard/2019/1236/eng@2019-12-31?m=pdf https://www.laws.africa mailto:info@laws.africa Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Contents Paragraph – Introduction .................................................................................................................................................................................. 1 Subparagraph 0.1 .......................................................................................................................................................................................... 1 Subparagraph 0.2 .......................................................................................................................................................................................... 1 Subparagraph 0.3 .......................................................................................................................................................................................... 1 Subparagraph 0.4 .......................................................................................................................................................................................... 1 Subparagraph 0.5 .......................................................................................................................................................................................... 1 Subparagraph 0.6 .......................................................................................................................................................................................... 1 Subparagraph 0.7 .......................................................................................................................................................................................... 1 Paragraph 1 – Scope .......................................................................................................................................................................................... 1 Subparagraph 1.1 .......................................................................................................................................................................................... 1 Subparagraph 1.2 .......................................................................................................................................................................................... 1 Paragraph 2 – Normative references ........................................................................................................................................................... 2 Subparagraph 2.1 .......................................................................................................................................................................................... 2 Subparagraph 2.2 .......................................................................................................................................................................................... 2 Subparagraph 2.3 .......................................................................................................................................................................................... 2 Subparagraph 2.4 .......................................................................................................................................................................................... 2 Subparagraph 2.5 .......................................................................................................................................................................................... 2 Subparagraph 2.6 .......................................................................................................................................................................................... 2 Subparagraph 2.7 .......................................................................................................................................................................................... 2 Subparagraph 2.8 .......................................................................................................................................................................................... 2 Subparagraph 2.9 .......................................................................................................................................................................................... 2 Subparagraph 2.10 ........................................................................................................................................................................................ 2 Subparagraph 2.11 ........................................................................................................................................................................................ 2 Subparagraph 2.12 ........................................................................................................................................................................................ 2 Subparagraph 2.13 ........................................................................................................................................................................................ 2 Subparagraph 2.14 ........................................................................................................................................................................................ 2 Subparagraph 2.15 ........................................................................................................................................................................................ 2 Subparagraph 2.16 ........................................................................................................................................................................................ 2 Subparagraph 2.17 ........................................................................................................................................................................................ 2 Subparagraph 2.18 ........................................................................................................................................................................................ 2 Subparagraph 2.19 ........................................................................................................................................................................................ 2 Subparagraph 2.20 ........................................................................................................................................................................................ 3 Subparagraph 2.21 ........................................................................................................................................................................................ 3 ii Subparagraph 2.22 ........................................................................................................................................................................................ 3 Subparagraph 2.23 ........................................................................................................................................................................................ 3 Subparagraph 2.24 ........................................................................................................................................................................................ 3 Paragraph 3 – Definitions ................................................................................................................................................................................ 3 Subparagraph 3.1 .......................................................................................................................................................................................... 3 Subparagraph 3.2 .......................................................................................................................................................................................... 3 Subparagraph 3.3 .......................................................................................................................................................................................... 3 Subparagraph 3.4 .......................................................................................................................................................................................... 3 Subparagraph 3.5 .......................................................................................................................................................................................... 3 Subparagraph 3.6 .......................................................................................................................................................................................... 3 Subparagraph 3.7 .......................................................................................................................................................................................... 3 Subparagraph 3.8 .......................................................................................................................................................................................... 3 Subparagraph 3.9 .......................................................................................................................................................................................... 3 Subparagraph 3.10 ........................................................................................................................................................................................ 3 Subparagraph 3.11 ........................................................................................................................................................................................ 3 Subparagraph 3.12 ........................................................................................................................................................................................ 3 Subparagraph 3.13 ........................................................................................................................................................................................ 3 Subparagraph 3.14 ........................................................................................................................................................................................ 3 Subparagraph 3.15 ........................................................................................................................................................................................ 3 Subparagraph 3.16 ........................................................................................................................................................................................ 3 Subparagraph 3.17 ........................................................................................................................................................................................ 3 Subparagraph 3.18 ........................................................................................................................................................................................ 3 Subparagraph 3.19 ........................................................................................................................................................................................ 3 Subparagraph 3.20 ........................................................................................................................................................................................ 4 Subparagraph 3.21 ........................................................................................................................................................................................ 4 Subparagraph 3.22 ........................................................................................................................................................................................ 4 Paragraph 4 – Requirements ........................................................................................................................................................................... 4 Subparagraph 4.1 – Requirements for point source/stack emissions ....................................................................................... 4 Subparagraph 4.2 – Requirements for ambient air quality .......................................................................................................... 6 Paragraph 5 – Testing ........................................................................................................................................................................................ 9 Subparagraph 5.1 .......................................................................................................................................................................................... 9 Subparagraph 5.2 .......................................................................................................................................................................................... 9 Subparagraph 5.3 .......................................................................................................................................................................................... 9 Paragraph 6 – Monitoring ................................................................................................................................................................................ 9 Subparagraph 6.1 .......................................................................................................................................................................................... 9 iii Subparagraph 6.2 .......................................................................................................................................................................................... 9 Subparagraph 6.3 .......................................................................................................................................................................................... 9 Subparagraph 6.4 ........................................................................................................................................................................................ 10 Subparagraph a. ................................................................................................................................................................................... 10 Subparagraph b. ................................................................................................................................................................................... 10 Subparagraph c. .................................................................................................................................................................................... 10 Subparagraph d. ................................................................................................................................................................................... 10 Subparagraph 6.5 ........................................................................................................................................................................................ 10 Subparagraph 6.6 ........................................................................................................................................................................................ 10 Paragraph 7 – Compliance ............................................................................................................................................................................ 10 Annex A ................................................................................................................................................................................................................. 10 iv Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana Ghana Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions Standard 1236 of 2019 Published on 31 December 2019 Commenced [This is the version of this document from 31 December 2019.] [The publication date of this work could not be ascertained. We used the date 31 December 2019 because the work was published during the course of the year 2019.] 0. Introduction 0.1 Ghana recognizes the need to reduce air pollution from stationary, aerial, mobile and non-point sources to levels which minimize harmful effects on public health, paying particular attention to sensitive populations such as the elderly, children and pregnant women, and the environment. 0.2 It is important to control emissions of pollutants at source and to identify and implement the most effective emission reduction measures at national, regional and local levels. Therefore, emissions of harmful air pollutants should be prevented, minimized or controlled through the implementation of relevant standards and guidelines. 0.3 Ghana stands to benefit by applying resource-efficient, less polluting and best available technologies and practices. 0.4 Clean air is essential to maintaining the delicate balance of life on this planet. Poor air quality is a result of a number of factors, including emissions from various sources, both natural and anthropogenic. Poor air quality occurs when pollutants reach concentrations which may endanger public health and/or the environment. Our everyday lifestyles, such as choices of transportation, open burning of waste, source of energy for industrial, domestic and commercial activities etc. can have significant impacts on air quality and public health. 0.5 This first Ghana Ambient Air Quality, Point Source or Stack Emission Standard is derived from data collected by the Ghana Environmental Protection Regulator and research institutions in Ghana. 0.6 Standards for clean air are very important instruments for protecting environment and public health. The evidence that regulation of air-quality has the concomitant result of protecting public health is based on a broad range of interdisciplinary research findings. Diseases and disorders associated with exposure to air pollution tend to be widely distributed across populations. 0.7 Due to the potential adverse environmental and public health implications of air pollution, Ghana intends in the immediate to long term, to improve the air quality for the entire population. 1 Scope 1.1 This Ghana standard specifies the requirements and test methods for ambient air quality. 1.2 It also specifies the requirements and test methods for point source or stack emissions based on the sources of energy. By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 1 https://commons.laws.africa/akn/gh/act/standard/2019/1236/media/publication/gh-act-ord-2019-1236-publication-document.pdf https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana 2 Normative references The following standards contain provisions which through reference in this text, constitute provisions of this standard. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards. 2.1 AS 3580.4.1, Methods of sampling and analysis of ambient air — Determination of Sulphur Dioxide — Direct reading instrumental method 2.2 ASTM D3162-12, Standard test method for carbon monoxide in the atmosphere (continuous measurement by non-dispersive infrared spectrometry) 2.3 ASTM D3266-91, Standard test method for automated separation and collection of particulate and acidic gaseous fluoride in the atmosphere (double paper tape sampler method) 2.4 ASTM D4096 - 17, Standard Test Method for Determination of Total Suspended Particulate Matter in the Atmosphere (High—Volume Sampler Method) 2.5 ASTM D4323 - 15, Standard test method for hydrogen sulphide in the atmosphere by rate of change of reflectance 2.6 ASTM D5466 - 15, Standard test method for determination of volatile organic compounds in the atmospheres (canister sampling methodology) 2.7 ASTM D6209 - 13, Standard test method for determination of gaseous and particulate polycyclic aromatic hydrocarbons in ambient air (collection on sorbent-backed filters with gas chromatographic/ mass spectrometric analysis) 2.8 ASTM D6602 -13(2018), Standard practice for sampling and testing of possible carbon black fugitive emissions or other environmental particulate, or both 2.9 ASTM D7773-12, Standard test method for determination of volatile inorganic acids (HCI, HBr and HNO3) using filter sampling and suppressed ion chromatography 2.10 California EPA Method 425, Determination of total chromium and hexavalent chromium emissions from stationary sources 2.11 ISO 7996, Ambient air — Determination of the mass concentration of nitrogen oxides — Chemiluminescence method 2.12 ISO 9096, Stationary source emissions — Manual determination of mass concentration of particulate matter 2.13 ISO 9855, Ambient Air — Determination of the particulate lead content of aerosols collected on filters — Atomic absorption method 2.14 ISO 10849, Stationary source emissions — Determination of the mass concentration of nitrogen oxides — Performance characteristics of automated measuring systems 2.15 ISO 13964, Air Quality — Determination of ozone in ambient air — ultraviolet photometric method 2.16 ISO 15713, Stationary Source emissions — Sampling and determination of gaseous fluoride content 2.17 ISO 17733, Workplace air — Determination of mercury and inorganic mercury compounds — Method by cold-vapour atomic absorption spectrometry or atomic fluorescence spectrometry 2.18 ISO 21438-2, Workplace atmospheres — Determination of inorganic acids by ion chromatography — Part 2: Volatile acids, except hydrofluoric acid (hydrochloric acid, hydrobromic acid and nitric acid) 2.19 USEPA Method 10, Determination of carbon monoxide emissions from stationary sources (instrumental analyzer procedure) By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 2 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana 2.20 USEPA Method 23, Determination of Polychlorinated dibenzo-p-Dioxins and Polychlorinated dibenzofurans from stationary sources 2.21 USEPA Method 29, Determination of metals emission from stationary sources 2.22 USEPA Method 0050, Isokinetic HCl/Cl2 2.23 USEPA Method 0061, Determination of hexavalent chromium emissions from stationary sources 2.24 USEPA Method 426, Determination of Cyanide Emissions from Stationary Sources 3 Definitions For the purpose of this Ghana standard, the following definitions apply: 3.1 regulator statutory body responsible for air quality 3.2 air pollution contamination of indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere 3.3 ambient air refers to outdoor air in our surrounding environment 3.4 ambient air quality the quality of outdoor air in our surrounding environment 3.5 atmospheric emission any release emanating from a point, non-point or mobile source that changes the composition of the air 3.6 black carbon is formed through the incomplete combustion of fossil fuels, biofuel and biomass, and is emitted as part of anthropogenic and naturally occurring soot. It consists of pure carbon in several linked forms 3.7 chimney stack or final exit duct on a stationary system used for the dispersion of residual process gases and particulates 3.8 fenceline key field locations, including along pipelines, at factory perimeters and even along rooflines 3.9 gaseous fuels refers to any one of a number of fuels that under ordinary conditions are gases. Example liquified petroleum gas (LPG), biogas and natural gas 3.10 hood any device that removes airborne grease, combustion products, fumes, smoke, heat, and steam from the air by evacuation of the air and filtration 3.11 incinerator an enclosed device that burns waste materials under controlled temperature until the material is reduced to ash 3.12 liquid fuels can be natural fuels (mainly used in engines, and in boilers and large and slow engines) and manufactured (or artificial) fuels (mainly alcohols, biofuels and products from the synthesis of hydrocarbons and coal) 3.13 mobile source identifiable source(s) of air emissions which does not emanate from a fixed location 3.14 non-point source a source of air emissions which cannot be identified as having emanated from a single identifiable source or fixed location, and includes open fires, industrial and agricultural activities 3.15 oxides of nitrogen (NOx) nitric oxide and nitrogen dioxide 3.16 PM2.5 particulate matter with aerodynamic diameter of less than 2.5 micrometre 3.17 PM10 particulate matter with aerodynamic diameter of less than 10 micrometre 3.18 point source a single identifiable source and fixed location of air emission and includes stacks, chimneys, hoods among others 3.19 stack a shaft for ventilation or passage of smoke By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 3 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana 3.20 solid fuels refers to various types of materials that are used as fuel in the solid state 3.21 total suspended particulate matter an airborne particulate matter representing a complex mixture of organic and inorganic substances, covering a wide range of diameters, from <0.1 µm and up to some 100 µm. 3.22 undertaking any enterprise, activity, scheme of development, construction, project, structure, building, work, investment, plan, programme and any modification, extension, abandonment, demolition, rehabilitation or decommissioning of such undertaking, the implementation of which may have a significant impact 4 Requirements 4.1 Requirements for point source/stack emissions The maximum limits for the corresponding pollutant based on source of fuel/type of energy used as given in column 2 of Table 1. The point source/stack emissions are measured in accordance with the relevant test methods specified in column 3 of Table 1 Table 1: Requirements for point source/stack emission # Pollutants Maximum limits Test method 1. Solid fuels a. Sulphur Dioxide (mg/ Nm3)* 200 USEPA Method 6C b. Oxides of Nitrogen (mg/Nm3) 200 ISO 10849 c. Particulate Matter (mg/ m3) 50.00 ISO 9096 2. Liquid fuels a. Sulphur Dioxide (mg/ Nm3) 500 USEPA Method 6C b. Oxides of Nitrogen (mg/Nm3) 400 ISO 10849 c. Particulate Matter (mg/ m3) 50.00 ISO 9096 By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 4 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana Table 1: Requirements for point source/stack emission 3. Gaseous fuels a. Sulphur Dioxide (mg/ Nm3) 100 USEPA Method 6C b. Oxides of Nitrogen (mg/Nm3) 320 ISO 10849 c. Particulate Matter (mg/ m3) 20.00 ISO 9096 4. Electrical energy a. Sulphur Dioxide (mg/ Nm3) 200 USEPA Method 6C b. Oxides of Nitrogen (mg/Nm3) 200 ISO 10849 c. Particulate Matter (mg/ m3) 50.00 ISO 9096 5. Incinerators a. Sulphur Dioxide (mg/ Nm3) 200 USEPA Method 6C b. Oxides of Nitrogen (mg/Nm3) 400 ISO 10849 c. Particulate Matter (mg/ m3) 70.00 ISO 9096 6. Other parameters (that may apply a. Carbon Monoxide (mg/ Nm3) 100 USEPA Method 10 b. Hydrochloric Acid (HCl) (mg/Nm3) 60.00 USEPA Method 0050 By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 5 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana Table 1: Requirements for point source/stack emission c. Hydrogen Fluoride (mg/Nm3) 4.00 ISO 15713 d. Mercury and mercury compounds (mg/Nm3) 0.03 USEPA Method 29 e. Particulate Lead (mg/ m3) (expressed as lead) 0.50 USEPA Method 29 Note: 1) Electrical Energy usage include induction/electric arc furnaces, dryers, oven, kilns, Alumina & iron smelting among others. 2)* N represents Normal atmosphere and pressure 4.2 Requirements for ambient air quality For requirements for ambient concentrations of air pollutants see Table 2. Table 2 – ambient air pollutants -Maximum limits # Substance Maximum limits Averaging time Test method 520 1 hour1 Sulphur Dioxide(SO2), µg/ m3 50 24 hours AS 3580.4.1 250 1 hour2 Nitrogen Oxides (measured as NO2), µg/m3 150 24 hours ISO 7996 150 24 hours3 Total Suspended Particulate matter, µg/m3 80 1 year ASTM D4096 - 17 70 24 hours4 PM10, µg/m3 70 1 year ASTM D4096 - 17 5 PM2.5, µg/m3 35 24 hours ASTM D4096 - 17 By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 6 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana Table 2 – ambient air pollutants -Maximum limits 6 Black Carbon, µg/ m3 25 24 hours ASTM D6602 -13 7 Benzene, µg/m3 5 1 year ASTM D5466 - 15 0.5 1 year8 Lead, µg/m3 1 24 hours ISO 9855 Table 3 – Fenceline air pollutants – Maximum limits # Substance Maximum limits Averaging time Test method 100 15 minutes 60 30 minutes 30 1 hour 1 Carbon Monoxide, mg/m3 10 8 hours ASTM D3162-12 2 Hydrogen Sulphide, µg/m3 150 24 hours ASTM D4323 15 3 Hydrogen Cyanide, µg/m3 220 24 hours USEPA Method 426 4 Hydrogen Chloride, µg/m3 20 24 hours ASTM D7773-12 / ISO 21438-2 5 Cadmium, ng/m3 3 1 year ISO 9855 6 Sulphur Dioxide (SO2), µg/m3 150 24 hours AS 3580.4.1 7 k Nitrogen Oxides (measured as NO2), µg/m3 150 24 hours ISO 7996 By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 7 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana Table 3 – Fenceline air pollutants – Maximum limits 150 24 hours8 Total Suspended Particulate, µg/m3 100 1 year ASTM D4096 17 70 24 hours9 PM10, µg/m3 70 1 year ASTM D4096 17 10 PM2.5, µg/m3 35 24 hours ASTM D4096 17 11 Black Carbon, µg/m3 25 24 hours ASTM D6602 13 12 Benzene, µg/m3 5 1 year ASTM D5466 15 1 24 hours13 Lead, µg/m3 0.5 1 year ISO 9855 15 24 hours14 Mercury (and its derivatives compounds), ng/m3 µg/m3 1 1 year ISO 17733 15 Cadmium, ng/m3 5 1 year ISO 9855 16 Manganese, µg/m3 1 24 hours ISO 9855 17 Toluene, mg/m3 8 24 hours ASTM D5466 15 18 Arsenic, ng/m3 15 24 hours USEPA Method 29 19 Fluoride, µg/m3 10 24 hours ASTM D3266-91 20 Ozone, µg/m3 120 8 hours ISO 13964 By Laws.Africa and contributors. 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Share widely and freely. 8 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana Table 3 – Fenceline air pollutants – Maximum limits 21 Nickel, ng/m3 20 1 year USEPA Method 29 22 PAH, ng/m3 1 1 hour ASTM D6209 13 23 Xylene, µg/m3 700 1 year 24 Dichloromethane (Methylene chloride), mg/m3 3 24 hours OSHA Method No 80 25 Trichloroethane, mg/m3 0.7 24 hours OSHA Method No 14 0.1 24 hours26 Dioxins/Furans, pg TEQ/m3 0.6 1 year USEPA 23 0.6 24 hours27 Total PCB, pg TEQ/m3 0.035 1 year GC-MS 5 Testing 5.1 Equipment used for measurement of all pollutants shall be approved by the regulator. 5.2 The testing laboratories shall use the test methods prescribed in this Ghana Standard or any equivalent International Standard test methods or other standard measuring instruments as shall be approved by the regulator for air quality monitoring. 5.3 Measuring instruments shall for the purpose of this standard include any approved device to indicate or record air pollution or give warning of excessive air pollution. 6 Monitoring 6.1 Measurements of air quality (ambient and point source) shall take place at any facility as determined by the regulator. 6.2 An Owner or Operator of any premises shall provide the regulator or any other officer duly authorized by the regulator every reasonable assistance or facility available at the premises that the officer may require for the purpose of taking an action required to be undertaken under this standard in respect of the premises. 6.3 Measurement of fenceline air quality and point source/stack air emission shall be carried out by the undertakings and records kept. The records shall be open for inspection by the officers of the regulator as and when required. By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 9 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by Environment and Health Protection – Requirements for Ambient Air Quality and Point Source/Stack Emissions (Standard 1236 of 2019) Ghana 6.4 The regulator shall determine: a. the number of sampling locations; b. the sampling duration; c. frequency of monitoring air quality at any undertaking; and d. frequency of submission of air quality monitoring report. 6.5 Every undertaking with a point source shall have an opening approved by the regulator on each stack, chimney, hood etc. for the measurement of air emissions. 6.6 The regulator shall establish a network of air quality monitoring stations in Ghana to monitor the trends in ambient air quality for policy formulation. 7 Compliance An undertaking shall be deemed to have complied with the requirements of this standard if after measurement and monitoring, the results show that emission does not exceed limits presented in tables as prescribed under clause 4. Annex A (Informative) Meaning of units used under clause 4 µg/m3 microgram per cubic metre mg/m3 milligram per cubic metre ng/m3 nanogram per cubic metre mg/Nm3 milligram per normal cubic metre pgTEQ/m3 Picogram toxic equivalents per cubic metre TEQ Toxic equivalents N normal conditions (standard atmosphere = 101.325kPa) By Laws.Africa and contributors. Licensed under CC-BY. Share widely and freely. 10 https://edit.laws.africa/widgets/pdf-attribution https://edit.laws.africa/widgets/pdf-cc-by