Pollution Control

Report 6: Executive summary

Report 5: Executive summary

Report 4: Executive summary

Report 3: Executive summary

Report 2: Executive summary

Report 1: Executive summary

Air quality progess report 2023

 



Report 6: Executive summary

This sixth interim report has considered all of the monitoring data gathered since the start of monitoring in February 2024.

It is evident from the frequent and repeated use of the Jerome at monitoring positions in the community around the landfill that concentration levels of Hydrogen Sulphide have fallen from higher levels observed earlier in the year with few occurrences of detectable levels in recent months.  At the same time, the incidence of odour considered to be related to landfill gas has declined as has the number of complaints.  The concentration of Hydrogen Sulphide and  Volatile Organic Compounds detected by diffusion tubes has remained below guidance values for intermediate/lifetime exposure throughout the monitoring to date.

This sixth interim report has provided opportunity for review of all the monitoring data gathered since February 2024 to be considered.

In this context, the community monitoring programme will therefore focus on the measurement of Hydrogen Sulphide using diffusion tubes at D1-D12 along with the data gathered by Pembrokeshire County Council at the fixed position monitor located at Spittal School.  This flexible strategy will be subject to continual review. 

Air Quality Report 6



Report 5: Executive summary

This interim report summarises the data gathered from the ongoing monitoring around Withyhedge Landfill. The monitoring includes diffusion tubes for the assessment of Hydrogen Sulphide and Volatile Organic Compounds (VOCs) that provide averaged concentrations over a defined period, and instantaneous measurements of Hydrogen Sulphide using a Jerome analyser. The monitoring programme is primarily aimed at gathering quantitative data to provide lines of evidence to help assess risks from the exposure to off-site air quality.

Comparison of the Hydrogen Sulphide concentrations detected using diffusion tubes with health-based criteria indicates that the concentrations continue to be below the guidance values for intermediate/lifetime exposure. At many positions Hydrogen Sulphide is not found above the analytical level of detection.

Monitoring of Volatile Organic Compounds (VOC) has also revealed many VOCs to be present at very low levels and below evaluation criteria, where available.

Using a hand-held instrument, known as a Jerome, Hydrogen Sulphide concentrations have been logged at different locations. Many readings are below the detection limit and a 30- minute nuisance threshold of 5 ppb has not been exceeded throughout the latest monitoring period. In combination, the data suggests that Hydrogen Sulphide is either not present at detectable levels or present at very low levels that fall below available guideline values.

Air quality monitoring interim summary report - 5

 

Report 4: Executive summary

This interim report summarises the data gathered from the ongoing monitoring around Withyhdege Landfill. The monitoring now includes diffusion tubes for the assessment of Hydrogen Sulphide and Volatile Organic Compounds (VOCs) that provide averaged concentrations over a defined period and instantaneous measurements of Hydrogen Sulphide using a Jerome analyser. The monitoring programme is primarily aimed at gathering quantitative data to provide lines of evidence to help assess risks from the exposure to off-site air quality.

Comparison of the Hydrogen Sulphide concentrations detected using diffusion tubes with health-based criteria indicates that the concentrations continue to be below the guidance values for intermediate/lifetime exposure.

Monitoring of Volatile Organic Compounds (VOC) has revealed many VOCs to be present at very low levels and below evaluation criteria, where available. This monitoring is to cease.

Using a hand-held instrument, known as a Jerome, Hydrogen Sulphide concentrations have been logged at different locations. Many readings of Hydrogen Sulphide reported by the Jerome analyser during the latest monitoring period are close to or below the detection limit and there are few recorded values above a 5ppb guideline value. It is evident from the repeated use of the instrument at different times of the day over several days that such concentrations are not persistent over such time-frames. At many monitoring positions on different occasions the Jerome did not detect Hydrogen Sulphide above the level of detection.

Air quality monitoring summary report - 4

 

Report 3: Executive summary

This interim report summarises the data gathered from the ongoing monitoring around Withyhdege Landfill.  The monitoring now includes diffusion tubes for the assessment of Hydrogen Sulphide and Volatile Organic Compounds (VOCs) that provide averaged concentrations over a defined period and instantaneous measurements of Hydrogen Sulphide using a Jerome analyser.  The monitoring programme is primarily aimed at gathering quantitative data to provide lines of evidence to help assess risks from the exposure to off-site air quality that is impacted by the landfill.

Comparison of the Hydrogen Sulphide concentrations detected using diffusion tubes with health-based criteria indicates that the concentrations continue to fall below these guidance values for intermediate/lifetime exposure.

For the first time, monitoring of Volatile Organic Compounds (VOC) has been undertaken during the latest exposure period.  The testing has revealed many VOCs to be present at very low levels and below evaluation criteria, where available.

Using a hand-held instrument, known as a Jerome, Hydrogen Sulphide concentrations have been logged at different locations.  In combination with an assessment of the odour perceived at the time of sampling, this monitoring has revealed variations in the concentration of Hydrogen Sulphide, but the dataset is complex and many readings are close to the detection limit of the instrument.  Higher values of Hydrogen Sulphide reported by the instrument are typically associated with the presence of odour and several different types of odour have been observed.  At times, the Hydrogen Sulphide concentration has been found to be higher than 5ppb with almost 15ppb detected in the community areas for short durations (<30 minutes) and higher concentrations at the landfill site. Concentrations above 5ppb have been found associated with different odour sources including landfill gas and agricultural activities.  The highest concentrations of Hydrogen Sulphide tend to be found when odorous landfill gas is suspected to be present.

Air quality monitoring summary report - 3

 

Report 2: Executive summary

This is the second interim reporting summarising the data gathered from the ongoing monitoring around Withyhdege Landfill. The monitoring now includes diffusion tubes for the assessment of Hydrogen Sulphide and Volatile Organic Compounds (VOCs) that provide averaged concentrations over a defined period and instantaneous measurements of Hydrogen Sulphide using a Jerome analyser. The monitoring programme is primarily aimed at gathering quantitative data to provide lines of evidence to help assess risks from the exposure to off-site air quality that is impacted by the landfill.

Comparison of the Hydrogen Sulphide concentrations detected using diffusion tubes with health-based criteria indicates that the concentrations continue to fall below these guidance values for intermediate/lifetime exposure.

For the first time, monitoring of Volatile Organic Compounds (VOC) has been undertaken during the latest exposure period. The testing has revealed many VOCs to be present at very low levels and below evaluation criteria, where available.

Using a hand-held instrument, known as a Jerome, Hydrogen Sulphide concentrations have been logged at different locations. Initial consideration of the data gathered indicates that the values recorded have been above and below a 5ppb guideline value and that these values have been recorded when an odour is detectable / reported and at times when an odour has not been detectable. Ongoing monitoring using the Jerome is focussing on logging data for 30-minutes at 5-minute sampling intervals at the same position as the diffusion tubes. This data will be evaluated in the next data monitoring summary alongside a comparison of the results gathered by different Jerome monitors.

Air quality monitoring summary report - 2

 

Report 1: summary

Air quality monitoring summary report - 1 

Public Health Wales Evaluation (opens in a new tab) 

 

The attached tables show a summary of the monitoring results showing 30 minute averages 

Table A

Date	Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Wind direction (from)	Wind direction likely to impact at receptor	Wind speed
08-May	00:09:26	B4329 Junction - Poyston Cross what3words = wound.hardening.butternut	0.4	No wind	N/NNW	No wind
08-May	07:20:48	Corner Piece Inn	13.5	No wind	W/WSW	No wind
12-May	22:26:26	SA62 5QR - Opposite Oakvale, Spittal what3words = truly.creatures.smoker	2.0	South South West / South	S/SW	Light
14-May	14:03:26	Corner Piece field what3words - stud. Supplied. Strongman Location chosen due to landfill odours.	2.2	South East	W/WSW	Light
26-May	08:03:01	6) Spittal Primary School	0.0	South West	S/SW	None - Light
10-Jun	04:25:06	what3words: expansion.traffic. fondest	4.8	North West	N/NNW	Steady/Strong

 

Table B

21st March 24

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
10:04:13	D4	3.0	Intermittent 'sweet' odour	no data	no data	SW	no data	not applicable
10:44:21	Spittal School	20.2	Intermittent odour	no data	no data	S/SW	no data	Includes a very high reading for first 5 minutes (117.07 ppb) of the monitoring period. If following the user manual the first 5 minute warmup cycle would not be included.
11:29:09	Treffgarne (adjacent church)	0.8	No detectable odour	no data	no data	S/SE	no data	not applicable
13:51:15	D9	0.0	No detectable odour	no data	no data	E	no data	not applicable
14:37:59	D1	3.7	No detectable odour	no data	no data	S	no data	not applicable
15:25:14	Opposite Spittal School	3.9	Intermittent odour	no data	no data	S/SW	no data	not applicable
16:17:43	Withybush Road, South of Haverfordwest	4.3	Intermittent odour	no data	no data	N	no data	not applicable

 

 22nd March 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
10:22:18	Treffgarne (adjacent church)	22.0	No odour detectable	NW	no data	S/SE	no data	not applicable
11:13:16	Spittal school	4.1	Weak odour	W	no data	S/SW	no data	not applicable
12:00:03	D6	4.1	No odour	NW	no data	W	no data	not applicable
13:03:03	D7	3.9	No odour	W	no data	N/NNE	no data	not applicable

 

3rd April 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
12:01:23	Ell's Kitchen	2.9	Weak odour	N	no data	N	no data	not applicable
12:55:53	A40 Rudbaxton Junction	4.5	Strong impersistent odour	N	no data	N	no data	not applicable
14:05:53	Spittal school	4.1	Impersistent 'sweet' odour	W	no data	S/SW	no data	not applicable
15:15:53	D7	4.0	No odour detectable	N	no data	N	no data	not applicable

 

 5th April 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
10:25:53	HfW County Hall	5.1	No odour	Gusting wind	no data	N/NNE	no data	Not enough data to calculate a 30 minute average - 25 minutes worth
11:45:52	Treffgarne (adjacent church)	5.0	Faint intermittent odour	E	no data	SE	Agri?	Not enough data to calculate a 30 minute average - 25 minutes worth
12:30:52	D1	4.9	Sweet' odour	S/SW	no data	S	Agri?	not applicable
13:15:53	Spittal school	6.7	Strong odour, pungent, landfill	S/SW	no data	S/SW	no data	not applicable
15:40:52	D7	4.6	No odour	S	no data	N/NNE	no data	not applicable
16:40:52	Palmerston Rd, Haverfordwest	5.1	No odour	S	no data	no data	no data	Not enough data to calculate a 30 minute average - 25 minutes worth

 

16th April 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
10:15:52	Spittal school	5.5	Weak odour	W/NW	no data	S/SW	no data	not applicable
11:40:52	Poyston cross	8.3	Strong pungent odour	W/NW	no data	N/NE	no data	not applicable

 

 23rd April 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
14:05:52	Spittal school	0.5	No odour	NW	no data	S/SW	no data	not applicable
14:55:53	D7	2.8	Faint intermittent unknown odour	NW	no data	N/NE	no data	not applicable

 

24th April 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
09:00:52	D10	3.9	Weak intermittent odour	no data	no data	E/ESE	no data	not applicable
09:40:52	D1	4.8	Sweet' odour	no data	no data	S	Agri?	not applicable
10:30:52	D2	3.1	Faint odour	no data	no data	S/SW	Agri?	not applicable
11:10:53	D3	4.3	No odour	no data	no data	S/SW	no data	not applicable
11:50:52	D4	4.5	Faint odour	no data	no data	SW	no data	not applicable
12:40:52	D5	4.8	Faint odour	no data	no data	W	Agri?	not applicable
13:20:52	D6	4.9	No odour	no data	no data	W	no data	Not enough data to calculate a 30 minute average - 25 minutes worth
13:55:52	D7	4.2	Faint odour	no data	no data	N/NNE	no data	not applicable
14:35:52	D8	4.7	No odour	no data	no data	NE	no data	not applicable
15:20:52	D9	4.8	Faint odour	no data	no data	NNE	no data	not applicable

 

26th April 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
13:15:53	D9	6.4	Faint odour	no data	no data	NE	no data	not applicable
13:55:52	D10	3.8	Strong odour	no data	no data	NNE	no data	not applicable
14:40:53	D1	0.0	Intermittent odour	no data	no data	NNE	no data	not applicable

 

29th April 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
11:05:53	D10	5.8	None	180 (S)	1.1	E/ESE	no data	not applicable
11:05:53	D1	6.7	Distinct	180 (S)	2.9	S	Landfill	not applicable
12:30:52	D2	5.2	None	180 (S)	5.8	S/SW	no data	not applicable
13:10:52	D3	5.5	Distinct	180 (S)	3.8	S/SW	Slurry	not applicable
13:50:52	D4	4.9	Faint	180 (S)	3.6	SW	Manure	not applicable
14:50:53	D8	4.8	None	180 (S)	3.1	NE	no data	not applicable
15:40:52	D9	4.3	None	180 (S)	0.4	NNE	no data	not applicable
16:25:53	D7	4.7	None	180 (S)	1.3	N/NNE	no data	not applicable
17:15:52	D6	4.2	None	210 (SW)	0.4	W	no data	not applicable

 

 

 30th April 2024

Start time of monitoring	Location	30 minute average concentration (ppb) compare to WHO ST level of 5 ppb	Odour detected	Wind direction (from)	Wind speed	Wind direction likely to impact at receptor	Site activities or other activities	Notes / commentary
12:15:52	D9	6.0	Faint	160 (SE)	0.1	NNE	Landfill	not applicable
13:10:52	D5	6.1	Faint	140 (SE)	0.6	W	Dung/nearby field	not applicable
13:55:52	D3	6.7	Faint	160 (SE)	1.1	S/SW	Slurry/dairy farm	not applicable
14:50:52	Treffgarne	6.9	Distinct	160 (SE)	0.1	SE	Landfill	not applicable

 

 

Air quality

The Environment Act 1995 and subsequent Regulations require Local Authorities to review and assess air quality in their area by the production of Updating and Screening Assessments every three years and annual Progress Reports for the intervening years. This Review and Assessment procedure represents the system for Local Air Quality Management (LAQM) which itself represents the main methodology in the UK Government's and the Devolved Administrations strategies to achieve relevant air quality objectives for Benzene, 1,3 Butadene, Carbon Monoxide, Lead, Nitrogen Dioxide, Particles and Sulphur Dioxide.