Công ước IPPC (International Plant Protection Convention) Công ước IPPC danh từ, trong tiếng Anh được dùng bởi cụm từ International Plant Protection Convention, viết tắt là IPPC. Công ước IPPC hay còn được gọi là Công ước Bảo vệ thực vật quốc tế, được ra đời vào năm 1952 bởi các nước thành viên của Tổ chức Lương thực và Nông nghiệp của Liên Hiệp Quốc (FAO). Đến tháng 7 năm 2012 , đã có 176 chính phủ và 1 tổ chức khu vực kí kết Công ước IPPC.
Monitoring timing considerations
Several timing considerations are relevant for setting monitoring requirements in permits, the main ones being:
- time when samples and/or measurements are taken
Frequency refers to the specific time intervals—such as hours, days, or weeks—when samples and measurements are collected This timing is essential for obtaining results that are pertinent to the Environmental Limit Values (ELV) and estimating loads, as it can be influenced by the processing conditions of the plant.
- when specified feedstock or fuels are being used
- when a process is operating at a specified load or capacity
When a process experiences upset or abnormal conditions, such as start-ups, leaks, malfunctions, momentary stoppages, or terminal shutdowns, a different monitoring approach is necessary due to potential pollutant concentrations exceeding normal measurement ranges This is crucial for effective compliance and management of emissions Additionally, in permits and related documents, the term "averaging time" refers to the period over which monitoring results are considered representative of the average load or concentration of emissions, which can vary from hourly to yearly For further details, please refer to Section 3.2.
An average value can be obtained in a number of different ways, including:
Continuous monitoring involves calculating an average value from results collected over a specific period Typically, a continuous monitor computes an average every 10 to 15 seconds, known as the averaging time of the monitoring equipment For instance, if a result is generated every 15 seconds, the average over a 24-hour period represents the mathematical mean of these results.
- sampling over the whole period (continuous or composite sample) to produce a single measurement result
- taking a number of spot samples over the period and averaging the results obtained.
Certain pollutants require a minimum sampling duration to ensure a measurable amount is collected, resulting in an average value for that period; for instance, dioxin measurements in gaseous emissions typically necessitate a sampling period of 6 to 8 hours The frequency of sampling refers to the interval between individual or grouped measurements of process emissions, which can vary significantly, ranging from one sample per year to continuous monitoring that operates 24 hours a day Monitoring methods are generally categorized into continuous and discontinuous, with campaign monitoring being a specific type of discontinuous monitoring.
When establishing measurement frequency, it is crucial to balance measurement requirements with emissions characteristics, environmental risks, sampling practicality, and costs Selecting a high frequency for simple and cost-effective surrogate parameters allows for subsequent monitoring of emissions at a reduced frequency.
Effective monitoring practices require aligning the frequency of assessments with the time frames in which harmful effects or trends may arise For instance, if short-term pollutant impacts pose risks, more frequent monitoring is essential Conversely, for risks associated with long-term exposure, a different approach may be warranted It is crucial to regularly review and adjust the monitoring frequency as new information about harmful effects becomes available.
Various methods exist for determining frequency, with risk-based approaches being the most prevalent For a detailed example of a risk-based approach, refer to Section 2.3 Additionally, alternative procedures, like the Capability Index, can also be utilized for frequency determination.
Campaign monitoring requires unique considerations for frequency determination, as it involves measurements taken in response to specific needs or interests This approach aims to gather more fundamental information than what is typically provided by routine or conventional monitoring methods.
The description of the Emission Limit Value (ELV) in the permit, including total amounts and peak levels, establishes the foundation for determining monitoring timing requirements It is essential that these requirements and the related compliance monitoring are explicitly defined and stated in the permit to prevent any ambiguity.
Monitoring timing requirements in permits are primarily influenced by the process type and emission patterns When emissions exhibit random or systematic variations, statistical parameters like means, standard deviations, and extremes only offer estimates of actual values Typically, increased sampling reduces uncertainty Additionally, the extent and duration of changes can significantly impact the necessary monitoring timing.
The philosophy of establishing timing requirements is exemplified by the variations in emissions depicted in Figure 2.5, which illustrates how emissions fluctuate over time The vertical axis represents emissions, while the horizontal axis denotes the passage of time, highlighting the dynamic relationship between these two factors.
Figure 2.5: Examples of how emissions can vary over time and their implications on determining monitoring time requirements
In the examples given in Figure 2.5 the determination of the time, averaging time and the frequency depends on the emission pattern as follows: ã Process A represents a very stable process.
The time when samples are taken is not important since the results are very similar irrespective of when the samples are taken (i.e in the morning, on Thursdays, etc.).
The averaging time is also not so important since whatever time we choose (e.g half-hour, 2 hours, etc.) the mean values are also very similar.
The frequency could therefore be discontinuous because the results would be very similar, independent of the time between them. ã Process B represents a typical example of a cyclic or a batch process.
Sampling and averaging times should be limited to the operational periods of the batch process; however, it is also valuable to consider average emissions throughout the entire cycle, including downtime, for accurate load estimation.
The frequency could be either discontinuous or continuous. ã Process C represents a relatively stable process with occasional short but high peaks, which contribute very little to the cumulative total emissions.
The focus of the Emission Limit Value (ELV) should be determined by the potential hazards of emissions, emphasizing either peak levels or total emissions When short-term pollutant impacts pose significant risks, prioritizing the control of peak emissions becomes crucial over managing cumulative pollution loads.
A very short averaging time is used for controlling the peaks, and a longer averaging time for controlling the total amount. ã Process D represents a highly variable process.
Again, the nature/potential hazard of the emissions will dictate whether an ELV is to be set for the peaks or for the total amount of emissions.
The timing of sample collection is crucial, as the variability inherent in the process can lead to significantly different results from samples taken at different times.
A very short averaging time is used for controlling the peaks, and a longer averaging time is used for controlling the total amount.
In either case a high frequency (e.g continuous) is likely to be necessary, since a lower frequency is likely to produce non-reliable results.
When determining the timing requirements for emissions limit values (ELVs) and related monitoring, several factors must be considered These include the duration of potential environmental harm, such as the immediate impact of air pollutants over 15 to 60 minutes, annual acid rain deposition, and varying exposure times for noise and wastewater Additionally, it is essential to account for process variations, the time needed to gather statistically representative data, and the response time of monitoring instruments Ultimately, the data collected should accurately reflect the intended monitoring targets and be comparable to data from other facilities, aligning with established environmental objectives.
How to deal with uncertainties
When monitoring is applied for compliance assessment it is particularly important to be aware of measurement uncertainties during the whole monitoring process.
Measurement uncertainty is a crucial parameter that reflects the variability of values that can be reasonably assigned to the measurand It indicates the degree to which measured values may differ from the true value, highlighting the inherent limitations in measurement accuracy.
Uncertainty in measurements is typically represented as a plus or minus interval with 95% statistical confidence There are two key types of dispersion relevant to uncertainties: "external dispersion," which indicates the variability in results from different laboratories using the same standards, and "internal dispersion," which reflects the consistency of results obtained by a single laboratory following the same standards.
Internal dispersion is utilized exclusively for comparing measurement results from the same laboratory using the same measurement process for the same measurand In contrast, external dispersion should be considered when estimating uncertainty in all other scenarios.
When a permit clearly defines a standard method for measuring regulated parameters, the term "external dispersion" refers to the uncertainty associated with that specific standard measurement method.
When the permit leaves open the choice of a standard method for the regulated parameter, the
External dispersion refers to the uncertainty associated with measurement results, encompassing systematic differences, or "bias," that may arise when comparing results obtained from various standard measurement methods for the same regulated parameter.
Systematic differences in measurement methods are theoretically negligible if all methods are traceable to SI units consistently In practice, traceability is often achieved through the use of Certified Reference Materials (CRMs) However, while CRMs can be utilized in analytical processes, their application is infrequent in the sampling stages of the data production chain.
To eliminate ambiguity, it is essential that the permit explicitly outlines the procedures for managing uncertainties Clear and concise procedures, such as stating "the result minus the uncertainty must be below the ELV" or "the average of N measurements should be below the ELV," are preferable to vague statements like "as low as reasonably practicable," which can lead to varied interpretations.
The compliance assessment procedure is influenced by statistical conditions that determine practical monitoring aspects, such as the required number of samples for achieving a specific confidence level When permits provide examples to illustrate this procedure, it is crucial to clarify that these examples are not restrictive but serve only as guidance Key components of the sampling process include developing a sampling plan, taking samples, pretreating samples (e.g., enrichment or extraction in the field), and ensuring proper transport, storage, and preservation Additionally, sample treatment, such as extraction and conditioning, along with thorough analysis and quantification, are essential steps in the overall assessment process.
When assessing uncertainties, it is essential to consider various external factors, including inaccuracies in flow measurements that affect load calculations, challenges in data handling such as missing values impacting daily averages, and discrepancies arising from systematic biases between different standard measurement methods for the same regulated parameter Additionally, uncertainties may stem from the use of secondary methods or surrogates, as well as inherent variability linked to processes or weather conditions.
Calculating the total uncertainty for a specific application can be challenging In the development of standards, such as CEN standards, this uncertainty is often assessed through interlaboratory testing and subsequently documented within the standards themselves.
Monitoring requirements to be included with Emission Limit Values (ELVs) in permits
Limit Values (ELVs) in permits
It is recommended that the permit writer consider the items addressed in the previous sections (Sections 2.1 – 2.6) before deciding on how to formulate the ELV in the permit.
When establishing emission limit values (ELVs) in a permit, it is essential to ensure that they can be practically monitored, that clear monitoring requirements accompany the ELVs, and that compliance assessment procedures are defined to facilitate understanding.
Equivalent Limit Values (ELVs) can encompass various parameters, including process conditions such as combustion temperature, equipment performance metrics like abatement efficiency, and emissions data indicating pollutant release rates or concentrations Additionally, flow characteristics such as exit temperature, velocity, and overall flow are critical, along with resource usage metrics that track energy consumption or pollution emitted per unit of production Lastly, the percentage capture of monitoring data is essential, representing the minimum required data percentage to establish accurate averages.
Understanding the connection between End-of-Life Vehicles (ELVs) and the monitoring program is crucial The monitoring requirements must comprehensively address all pertinent aspects of the ELV, and it is advisable to consider several key factors to ensure effective oversight.
It is essential to explicitly state in the permit that monitoring is a fundamental and legally binding requirement, emphasizing that adherence to monitoring obligations is equally important as complying with the specified limit values or equivalent parameters.
2 Specify clearly and unambiguously the pollutant or parameter being limited This may include specifying details such as, for instance:
- if a volatile substance is to be monitored, it should be clear whether this refers to the gaseous component and/or to the solid component attached to particulates
- if oxygen demand in water is to be monitored, it should be clear which test is to be used, e.g Biochemical Oxygen Demand 5 days test (BOD 5 )
- if particulates are to be monitored the size range should be specified, e.g total,