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1.1 Scope

1.1.1 Applied Environmental Research Centre Ltd (AERC) has been commissioned by Compound Security Systems (the client), to undertake a review of legislation associated with noise in the environment. The purpose of this assessment was to identify whether the "Mosquito" high frequency sound deterrent complies with current acoustic legislation.

1.2 Background

1.1.2 The "Mosquito" is a wall-mounted unit, similar in appearance to a small halogen-style wall light often seen outside residential properties. The unit has an effective range of between 15m and 25m, which emits pulses of high frequency sound ranging between 16 kHz –19kHz, which have been recorded at 76 dB(A) at 3m from the unit.

1.1.3 The unit works on the principle that the audible range of the human ear generally ranges between 20 Hz and 20 kHz, with the higher end of the audible spectrum being the first to deteriorate naturally due to an age related deafness called "presbycusis".

1.1.4 The device exploits the fact that by the time a person reaches their mid to late twenties there is a large drop in their ability to hear very high frequencies. Based on this natural phenomenon, the Mosquito emits high frequency sound, which can generally only be heard by people up to 20-25years of age.

1.1.5 The high frequency sound emitted from the unit, which cannot be heard by older people, has been designed to deter small crowds of anti social young people from congregating outside stores and shops.

1.1.6 Field trials throughout the UK have confirmed that juveniles and young people who have regularly congregated at known meeting places moved away to other areas after a few minutes exposure to the Mosquito. In addition, it is understood that there have been no reported incidents of noise complaints from residents living in close proximity to the "Mosquito" during its operation.

1.1.7 An independent test report conducted by the National Physical Laboratory (NPL) in December 2005 (Ref E05110518) identified that the Mosquito had a fundamental output with a mean frequency at 16.8kHz and maximum frequency at 18.6kHz, with an A-weighted sound pressure level at 3m of 76 dBA. NPL also confirmed that the Mosquito did not present a noise hazard when assessed against the criteria detailed in the current Noise at Work Regulation 1989 and those in the Control of Noise at Work Regulations 2005 (due to come into force 6th April 2006).

1.1.8 It is understood that Compound Security Systems has also commissioned an independent assessment, which confirmed that the Mosquito system complies with all Human Rights legislation.


2.1 Difference between sound and noise

2.1.1 Physically there is no distinction between sound and noise. Sound is a sensation detected in the ear as a result of pressure variations set up in the air by a vibrating force. Such vibrations set a series of alternate regions of increased and decreased pressure (compressions and rarefactions) in the surrounding air.

2.1.2 Noise has been defined in various terms, but is essentially unwanted sound which is undesired by the recipient.

2.1.3 Most environmental sounds are made up of a complex mix of many different frequencies. Frequency is the rate at which the source vibrates, and subsequently produces the pressure wave. It is measured in cycles per second (Hertz-Hz). Frequency determines the pitch of sound. Doubling of frequency produces an approximate increase of one octave

2.1.4 The frequencies that the normal human ear can detect (up to age 25 years) range from 20 Hz to 20kHz, although individuals can very greatly in terms of their sensitivity. Below 20Hz lies the range of infrasound and above 20kHz the ultrasound range.

2.1.1 The human hearing system is not equally sensitive to all sound frequencies, and to compensate for this, various filters or frequency weightings have been used to determine the relative strengths of frequency comments making up a particular environmental noise. The A-weighting is commonly used as it approximates the frequency response to our hearing system.

Compound Security Systems Review of Environmental Acoustic Legislation

Mosquito High Frequency Sound Deterrent


3.1 Introduction

3.1.1 Environmental regulation is achieved both through statute and common law. The following sections outlines the legislation which has a relevance to noise control.

3.2 Environmental Legislation

The Control of Pollution Act 1974 Part III (COPA)

3.2.1 COPA covers noise associated with construction and demolition sites S60-S61, which excludes the "Mosquito".

3.2.2 Noise in the street is covered by sub-section 62(1) and bans the use of loud speakers in the street between 21:00 hrs and 08:00hrs, although this section of the Act is now dealt with by the Noise and Statutory Nuisance Act 1993.

3.2.3 Under S64 of the Act, local authorities are able to designate noise abatement zones (NAZ); premises classified under the order usually industrial premises, may not exceed their registered level. The purpose of these is the long term control of noise from fixed noisy premises in order to prevent further increase in existing levels of environmental noise levels in the area, and to achieve a reduction wherever possible.

3.2.4 Following the implementation of a NAZ order, the local authority is required to record noise levels from the premises specified in the order. These are then kept by the local authority and available for public inspection.

3.2.5 Once a noise level has been registered it may not be exceeded. Over a period of time the local authority may seek to reduce the level initially registered under s.66 of the Act. Section 68 allows the Secretary of State to make regulations to reduce noise caused by plant or machinery, whether or not in a noise abatement zone. There is a right of appeal (s.70) to the Magistrates Court for three months from the date on the Noise Reduction Notice.

3.2.6 It is a defence to prove that the best practicable means were used to prevent or counteract the effect of the noise.

Environmental Protection Act 1990, Part III (EPA)

Statutory Nuisance

3.2.7 Part III of EPA deals with noise as a statutory nuisance and applies to England, Scotland and Wales. Section 79 places a duty on local authorities to inspect their areas from time to time to detect whether a nuisance exists or is likely to occur or re-occur. This section of the Act defines a statutory noise nuisance as "noise emitted from premises so as to be prejudicial to health or a nuisance". Nuisance is based on common law, and may be defined as an "unlawful interference with a persons use or enjoyment of land or some right over it, or in connection with it".

3.2.8 It should be noted that the Act interprets: "noise" to include vibration; "prejudicial to health" means injurious or likely to cause injury, to health; and "premises" includes

Compound Security Systems Review of Environmental Acoustic Legislation

Mosquito High Frequency Sound Deterrent

land and vessels (except those powered by "steam reciprocating machinery"). Noise from aircraft other than model aircraft is excluded.

3.2.9 Local authorities must also take reasonably practicable steps to investigate any complaint of statutory nuisance from a person living in its area.

3.2.10 The EPA does not define the level at which sound in the neighbourhood becomes a noise nuisance. This determination is made following an objective assessment by a local environmental health officer.

3.2.11 Where the local authority is satisfied that a statutory noise nuisance exists, or is likely to occur or re-occur it must issue the person(s) responsible for causing the nuisance with a noise abatement notice under S 80 requiring:

• the abatement of the nuisance or prohibiting or restricting its re-occurrence;

• the carrying out of the work necessary to abate the nuisance.

3.2.12 Failure to comply with the terms of the abatement notice without reasonable excuse may result in prosecution in the Magistrates Court (Sheriff's Court – Scotland). Conviction may result in a maximum fine of £5,000, plus a daily fine of £500 for each day the offence continues after the conviction. Where the conviction is for a noise offence associated with industrial, trade or business premises, the maximum fine is £20,000 (Sc:£40,000, ASB ACT2004).

3.2.13 The London local Authorities Act 2004 enables local authorities in London to issue fixed penalty notice in respect of a breach of, or failure to comply with an abatement notice served under the EPA.

3.2.14 Under ss 82(10) there is a defence when it can be proven that the best practicable means were used to prevent the nuisance from industrial trade or business premises.

The Noise and Statutory Nuisance Act 1993 (TNASNA)

3.2.15 This Act, covers England Scotland and Wales and amends ss.79-82 of the EPA to make noise emitted from a vehicle, machinery or equipment being used for industrial, trade or business purposes in the street (Scotland-road) a statutory nuisance.

3.2.16 The definition of noise in the street is given by "noise that is prejudicial to health or a nuisance and is emitted from or caused by a vehicle", machinery or equipment in the street" or in Scotland, road.

3.2.17 The Act defines equipment to include musical instruments. Guidance from the Department of the Environment, Transport and the Regions (Env Circular 9/97, WO 42/97) suggests that loud speakers tannoys, loudhailers, radios and "ghetto blasters" should also be regarded as equipment.

3.2.18 This could include: noisy car repairs', car alarms', car radios and parked refrigerated vehicles.

3.2.19 Local authorities have to take such steps which are reasonably practical to investigate any complaint from a person living in its area. Although there is no requirement to physically monitor noise levels, local authorities commonly use BS4142:1997 "Method for Rating Industrial Noise Affecting Mixed Residential and Industrial Areas". It can be used to determine the likelihood of noise complaints from an industrial source under normal operating conditions.

3.2.20 Having satisfied itself that a statutory nuisance exists or is likely to occur the local authority must serve an abatement notice.

3.2.21 TNASNA also amends the procedure for serving an abatement notice in respect of a nuisance from a vehicle, machinery or equipment (VEM) on the street. If the VEM is unattended then the notice may be attached directly to the VEM.

3.2.22 The Act covers loudspeakers, with section 7 placing restrictions on the hours they may be used in the street.

3.2.23 Section 9 and Schedule 3 of NASNA relates to "Audible Intruder Alarms". Generally speaking these apply to burglar alarms, and impose certain obligations on owners of the alarms, including:

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  • SHAUN MORRIS, Security Manager Northern Property, Yellowknife, NT

    The Mosquito works great for us, Our problem with panhandlers & homeless people hanging out has dramatically improved since we installed the mosquito.

    We left it on full time during business hours for the first few weeks and after that we were able to turn it off and just use it periodically as needed.

  • Carmen Ramirez, Park Avenue Enterprises LLC, New York, NY

    "It was amazing! Immediately the Mosquito effectively cleared out the loitering teens from the troubled area without hassle or confrontation."

  • Wade Rohloff, Graphic Safety, Hobbs, NM

    "The mosquito worked perfectly last night. I got it hooked up just in time for some kids to show up and make a lot of noise. After I turned it on they began complaining and left shortly thereafter. This thing is amazing."

  • Sarah Ward, PC 1623

    "Regarding the Mosquito apparatus that we have recently been using in our area, this is just a note to say that we have been extremely pleased with it.

    We have also had a positive reaction regarding its use from members of the public. In short, it has been an all-round success."

  • Lincolnshire Police

    "It is still presently sited at an old folks complex and is giving them a long awaited respite from ASB."

    Colin Hill PC 879
    Lincolnshire Police
    ASB Officer - South Holland District Council

  • David Meade, Millennium Place Primary Condominium, Boston, MA

    "The Mosquito has been effective. It has been implemented with other low echelon security measures and the results have been absolutely amazing. If the comparison prior to the mosquito install is made to present, we have seen a 95% to 98% decrease in activity and incidents in the stairwell."

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