5.2 Air

5.2.1 Application of Ambient Air Quality
Standards

Ambient air quality is defined in terms of air quality parameters which is a useful basis for legislation. Maintenance of desirable air quality is to ensure that the air quality standard has not been exceeded. When exceeded it can be made possible to prove that one or more specific cases are responsible. If exceeded, measures can be taken against those sources that are suspected of causing the worst pollution and require them to reduce pollution by the best practicable means available.

5.2.2 Approach Adopted

The draft framework legislation requires that standards be formulated in various sectors of the environment. With regard to air quality standards it gives the following:
- Stationary sources.
- Mobile sources.
- Working environment.
- manufacturing.
- Criteria and guidelines for air pollution control technology for both stationary and mobile sources.
- Guidelines for emission of greenhouse gases to control climate change.
- Concentration and nature of pollutants emitted.
- Analytical methods to monitor compliance.
- Establishment of laboratories.
- Emission reporting.

5.2.3 Methodology used in Developing Air Quality Standards

The following logical framework was used in developing the AQS
(1) a checklist of the type of enterprises and development activities that will be regulated was made and the type of emissions expected from them.

(2) Development of a check-list of the main environmental issues and the detailed parameters that need to be
addressed, within the context of Kenya's air pollution problems.

(3) Checking whether the selected parameters are well researched in as far as cause and effect relations has been established.

(4) a subjective consideration of whether the standards are enforceable in practice to serve their purpose. It was also prudent to ensure that the prescriptions are kept to the minimum. It is assumed that after the standards,
the enforcement may be elaborated in everyday permit or operating licences. In selecting the standards/guidelines the following were considered:

(i) Visual observations.
(ii) Aesthetics and possibility of having odorous effects.
(iii) Instrument monitoring.
(iv) Possibility of application of clean technology practices that reduce emission at source such as self monitoring, environmental audits, and certification by laboratories.

Literature was searched concerning practices in other countries and the setting of standards as well as the selection of the parameters for which standards were appropriate. It is apparent that countries have set standards for those parameters that are problematic in their own environment,
but a common criterion is apparent in the selection of air quality parameters and monitoring but it is a basis for decision-making for the regulatory agency methods.

5.2.4 Compliance and Enforcement

In order to be meaningful and effective, the standards developed should be easy to comply with and enforceable since establishment of an effective defence of the environment and of human health and welfare against air pollution is a complex process in which a number of tasks must be accomplished to achieve the goal of nationwide compliance. The government as the regulatory agent will have to carry out certain tasks to support the standards.
These include:
- the determination of acceptable exposure levels for the population;
- the determination of pollutant concentration in the air and of the adverse effects of the pollutants;
- evaluation of the concentrations that can be achieved in practice and the methods of achieving them; and,
- the choice of methodology for monitoring and surveillance of air pollution.

5.2.5 Comparison of International Practice Standards

Considering that this is the first time AQS are being developed for Kenya, it was important to learn from the experience of other countries.

The countries examined in the present review are Canada, Japan, Sweden, the United States, and the European Community (EC). In addition, the approaches of several EC Member States to the problem of atmospheric pollution control are also examined. We would have very much liked to use the examples of countries with similar circumstances to Kenya especially in Africa. There were none.

The general requirements and procedures for preventing or reducing emissions to air from industrial plants and processes are set out in the European Communities Framework Directive(84/360/EEC). It is the responsibility of each member state to use national standard methods of sampling and measurement to ensure compliance with the emission limits of the"daughter directive". For major industrial processes these have been or are being promulgated for different sectors of industry. For example, in France the Ministry of Environment has cited a number of processes for which there are limits to emissions to the air with specified procedures for their measurement and analysis while in Germany the sampling of gaseous and aqueous media is covered by DIN Standard which is almost the same case in Japan and the USA. A few examples from developing countries are mentioned below.

(a) Developing Countries

(i) Philippines

Monitoring and compliance of vehicle emissions with ADS is done by the Land Transport Office, Local Government Units, Philippine National Police, Department of Environment and National Resources. For stationary
sources monitoring compliance is done by DEAR (Regional Office) through permitting functions. It includes regulation of potential (emission) sources such as full quality. It is important to note that the Philippine's enforcement scheme does appear to link the control of emissions to a health based ambient standard. For industry the permit system ensures continuous emission monitoring of air with record keeping and reporting of the same; however, there is no regular follow-up to ensure compliance.

(ii) South Africa

Before independence in 1994, air pollution was under the Department of Health where scheduled processes were governed by individual permits and permit holders were required to report regularly to the Chief Air Pollution
Control Officer; however, there were only six (6) air pollution control officers for the whole country.

Local air pollution issues such as urban smokeless zones programmes were dealt with in the past at the municipal level. Currently, there is the Atmospheric Pollution Prevention Act (No. 45 of 1965) under which permits have been issued for scheduled processes on a case by case basis. Permit holders have been required to report regularly especially on particulate emissions; however, the Chief Air Pollution Control Officer's ability to enforce those provisions have been limited. Monitoring of gaseous emissions is rare in South Africa, but it is generally agreed that neither the government nor the private sector can accurately state the pollutants being emitted. A network of monitoring stations evaluating ambient air quality does exist.

(iii) Nepal

Use of pollution inventory-emission factors taken from publications of the US-EA and WHO are extensively used.
There is no actual physical monitoring however, inventories have force of law.

(iv) Hong Kong

The Environmental Protection Department (ED) operates a network of eight monitoring stations to provide comprehensive measurements of air quality throughout the year. At each station gaseous pollutants are measured continuously and particulate matter is sampled according to its size every 6 days. Air quality statistics is made on the basis of protecting public health most important pollutants are particulate matter and nitrogen dioxide.
(b) Developed Countries

Developed countries have air quality standards which have been effective in reducing air pollution. It could have been easy to prescribe air quality standards from developed countries. It was found useful to indicate current practices in developing countries with circumstances similar to Kenya's before standards could be proposed. Many countries have set AQS based on averaging time.

The following are the averaging times commonly uses. All measurements are at 298K (25°C)
(a) hourly averages not to be exceeded three times a year;
(b) 8-Hour averages not to be exceeded more than once per year; and,
(c) three months arithmetic means.

The averaging times selected are based on the method of measurement.

5.2.6 Priority Air Pollutants for Kenya

Air quality standards found necessary in order of priority include workplace and residential facilities, ambient atmospheres, selected stationary sources, and transport/ mobile sources.
In developing this priority list ,the following remarks are made:

(i) Workplace and Residential Facilities

The Factories Act is implementing AQS suggested by ILO and hence it was realised that it would amount to duplication of work if this was repeated. However, the expression "other places of work", places a limitation on the scope of addressing emission sources which do not fall within the definition of the Factories Act such as residential houses, sewerage treatment works and
agricultural activities.

(ii) Air Quality Limits in the Atmosphere

Because of the hitherto sectoral approach to AQS determinations for ambient air quality, there has been a confusion of the terms, units, codes of measurement, and monitoring criteria. The proposed AQS Limits will harmonise this.

These parameters are:
(a) Dust, particulate Matter and Aerosols
(b) Carbon monoxide
(c) Sulphur dioxide
(d) Carbon monoxide
(e) Lead

5.2.7 Standards Developed

The standards developed fall under the following broad areas:
(a) ambient air quality limits;
(b) general aspects, which are intended to harmonise language , units and references;
(c) emissions from stationary sources;
(d) mobile sources; and,
(f) guidelines for minimisation of emissions.

Limits

Limits on emissions to the atmosphere will be cited as concentrations averaged over time. In order to avoid the use of dilution to meet such limits, standards reference conditions must be specified.

Emitted concentrations of pollutants are usually specified at standard temperature and pressure (STP), that is 273 degrees centigrade and 101325 kPa (about 1 atmosphere).
Correction for water vapour is sometimes required so that results can be presented in terms of dry gas. The following shall apply for the ambient air emission limits). 74

5.2.8 General Aspects

(1) DKS/ISO 9745: Vocabulary

(2) DKS/ISO 4226: Units of measurement

(3) DKS1163930
Part 1: Guidelines for Planning the Sampling of atmosphere and Location of
monitoring stations.
Part 2: Sampling of gaseous pollutants.

(4) DKS/ISO8756: Handling of temperature, pressure and humidity data.

5.2.9 Standards Methods of Testing Ambient Atmospheres Pollutants

(5)DKS/ISO 7708: Particle size fraction definitions to health related sampling

(6)DKS/ISO 1163(3) Dusts and Particulate Matter: Determination of a black smoke index.

(7)DKS/ISO8186: Determination of the mass concentration of carbon monoxide -Gas concentration of carbon monoxide
- Gas chromatographic method.

5.2.10 Standard Methods of Measuring Stationary Source Emissions

(8) DKS/ISO(1163)/4: Determination of gaseous sulphur compounds in ambient air- sampling equipment.

9) DKS/ISO6767: Determination of the Mass Concentration of Sulphur dioxide -
t e t r a c h l o r o m e r c u r a t e ( T C M ) pararosaniline method.

5.2.11 Standard Methods of Measuring Pollutants from Mobile Sources

(10) DKS/ISO7644: Measurement of capacity of exhaust gas from compression- ignition(diesel) engines-Lug -down test.

(11) DKS/ISO3929: Apparatus for measurement of exhaust gas from diesel engines operating under steady state conditions.

5.2.12 Monitoring

The purposes for monitoring in the context of these standards are varied and may include any of the objectives stated below.

(i) Estimate the amount and composition of air pollution for an area.
(ii) Establish a database for trends in the degree of pollution with time, year to year or day to day.
(iii) Determine the source and dispersion of air pollution on the local, regional and global scale.
(iv) Determine the impact of air pollution on human health, animals, vegetation and materials.
(v) Ensure compliance with the above standards.
(vi) Assess impact of policy measure and their effectiveness.
(vii) Give short-term warning of pollution risks.

The methods used will vary from time to time. It is expected that the detailed methods of analysis of the parameters standardised here are many and they will not be reproduced here. It suffices to mention that the WHO has detailed these methods for general atmosphere.

Methods developed for work-place atmospheres are sometimes suitable for or can be adapted for the measurements of particulate and/or gases in process streams.

5.2.13 Sampling
Sampling in gaseous streams involves extractive techniques for both particulate and gases. Sampling for particulate is usually more difficult than for gases, as more account must be taken of the conditions of the gaseous environment and the characteristics of the particle. It is important to have definitions of the particle to be controlled and the method of analysis. Three gas samplers are suggested. They are BDX by Sensidyne of USA for lead and asbestos; Mini-GASS from Perma-Pure; and, Sieger Aspirated Gas Sampling System from Zellwegger Analytic (UK).

5.2.14 Data Analysis and Reporting

Data will be collected at site and in laboratories. Its analysis is crucial to decision making. Multi-parameters analysers are gaining ground, and, the following are suggested:

(i) Horiba Ltd 250.
(ii) Model 350 Ultraviolet photodiode analyses from Land Combustion(UK).
(iii) Drager Sensors.
(iv) Suspended particulate analytical method.

5.2.15 Inventories for Point Sources

It is common in large manufacturing enterprises to carry out inventories. The inventories give an idea of total emissions. Essential features and problems to note are the following:

(i) the low range of concentrations measured is related to an occupational exposure limit and is therefore low;
(ii) The moisture content in work-place atmospheres is usually low, but it can be very high in process streams;
(iii) process streams operate at a range of temperatures and pressures that may require special sampling systems; and,
(iv) in using gas detector tubes for measuring gas concentrations in a process stream, account should
be taken of other interfering gases.

5.2.16 Guidelines for Emission Control

It is most likely that not all emissions can be regulated. It is therefore, important to give an indication that potential polluters are making effort to minimise emissions. The guidelines stated below are suggested to meet the objectives indicated for each guideline.

(1) Guideline for Minimisation of Fugitive Gaseous Emissions

The objective is to minimise fugitive gases from selected sources in the sector of volatile organic compounds. Solvent standards are difficult to monitor since there are many diffuse sources and effective concentrations are low
considering the capacity of Kenya to monitor them.

(2) Minimising Emissions from Stationary Sources

The objective is to help potential polluters appreciate the air quality impacts of their activities for the stationary sources that can be controlled by reducing emissions at source such as industries and energy generation systems.

(a) The first point of control will be at the environmental impact assessment stage where a proponent will understand the processes that bring about air pollutants.
(b) Appreciation of the local environmental condition and the local authority's desired ambient air quality.
(c) Approvals of emission guidelines will take into consideration the application of the best available technology that is economically feasible.

(3) Procedure for Emissions Inventory

The objective is to assess potential emissions by Stoichiometric methods. The basis for the use and application of the guidelines will be on assessment of the:
(a) substances which are likely to be emitted from all sources including possible diffuse sources.
(b) mass flow volume for the various substances and groups of substances; and,
(c) volumes of each substance emitted to air;
(4) Chimneys and Fume Stacks

The objective is to ensure maximum dispersal and reduce exposure. The following guidelines will apply in the construction of chimneys.
(a) All chimneys and stacks for ventilation units should always be placed so that it is not possible for polluted air from the stack or chimney to enter through windows, doors, air intakes to ventilation unit or adjacent buildings of the premises or those of bours.

(b) Large-scale units such as energy generation, petrochemical refining, among others, should endeavour to use appropriate meterological and
computer model to calculate the dimensions of the fume stacks including the height.